When using the VMA iterator, the final execution will set the variable
'next' to NULL which causes the function to fail out. Restore the break
in the loop to exit the VMA iterator early without clearing NULL fixes the
issue.
Link: https://lore.kernel.org/lkml/29344.1666681759@jrobl/
Link: https://lkml.kernel.org/r/20221025161222.2634030-1-Liam.Howlett@oracle.com
Fixes: 763ecb0350 (mm: remove the vma linked list)
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: "J. R. Okajima" <hooanon05g@gmail.com>
Tested-by: "J. R. Okajima" <hooanon05g@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The kernel test robot flagged a recursive lock as a result of a conversion
from kmap_atomic() to kmap_local_folio()[Link]
The cause was due to the code depending on the kmap_atomic() side effect
of disabling page faults. In that case the code expects the fault to fail
and take the fallback case.
git archaeology implied that the recursion may not be an actual bug.[1]
However, depending on the implementation of the mmap_lock and the
condition of the call there may still be a deadlock.[2] So this is not
purely a lockdep issue. Considering a single threaded call stack there
are 3 options.
1) Different mm's are in play (no issue)
2) Readlock implementation is recursive and same mm is in play
(no issue)
3) Readlock implementation is _not_ recursive (issue)
The mmap_lock is recursive so with a single thread there is no issue.
However, Matthew pointed out a deadlock scenario when you consider
additional process' and threads thusly.
"The readlock implementation is only recursive if nobody else has taken a
write lock. If you have a multithreaded process, one of the other threads
can call mmap() and that will prevent recursion (due to fairness). Even
if it's a different process that you're trying to acquire the mmap read
lock on, you can still get into a deadly embrace. eg:
process A thread 1 takes read lock on own mmap_lock
process A thread 2 calls mmap, blocks taking write lock
process B thread 1 takes page fault, read lock on own mmap lock
process B thread 2 calls mmap, blocks taking write lock
process A thread 1 blocks taking read lock on process B
process B thread 1 blocks taking read lock on process A
Now all four threads are blocked waiting for each other."
Regardless using pagefault_disable() ensures that no matter what locking
implementation is used a deadlock will not occur. Add an explicit
pagefault_disable() and a big comment to explain this for future souls
looking at this code.
[1] https://lore.kernel.org/all/Y1MymJ%2FINb45AdaY@iweiny-desk3/
[2] https://lore.kernel.org/lkml/Y1bXBtGTCym77%2FoD@casper.infradead.org/
Link: https://lkml.kernel.org/r/20221025220108.2366043-1-ira.weiny@intel.com
Link: https://lore.kernel.org/r/202210211215.9dc6efb5-yujie.liu@intel.com
Fixes: 7a7256d5f5 ("shmem: convert shmem_mfill_atomic_pte() to use a folio")
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: kernel test robot <yujie.liu@intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kmap() and kmap_atomic() are being deprecated in favor of
kmap_local_page() which is appropriate for any thread local context.[1]
A recent locking bug report with userfaultfd showed that the conversion of
the kmap_atomic()'s in those code flows requires care with regard to the
prevention of deadlock.[2]
git archaeology implied that the recursion may not be an actual bug.[3]
However, depending on the implementation of the mmap_lock and the
condition of the call there may still be a deadlock.[4] So this is not
purely a lockdep issue. Considering a single threaded call stack there
are 3 options.
1) Different mm's are in play (no issue)
2) Readlock implementation is recursive and same mm is in play
(no issue)
3) Readlock implementation is _not_ recursive (issue)
The mmap_lock is recursive so with a single thread there is no issue.
However, Matthew pointed out a deadlock scenario when you consider
additional process' and threads thusly.
"The readlock implementation is only recursive if nobody else has taken a
write lock. If you have a multithreaded process, one of the other threads
can call mmap() and that will prevent recursion (due to fairness). Even
if it's a different process that you're trying to acquire the mmap read
lock on, you can still get into a deadly embrace. eg:
process A thread 1 takes read lock on own mmap_lock
process A thread 2 calls mmap, blocks taking write lock
process B thread 1 takes page fault, read lock on own mmap lock
process B thread 2 calls mmap, blocks taking write lock
process A thread 1 blocks taking read lock on process B
process B thread 1 blocks taking read lock on process A
Now all four threads are blocked waiting for each other."
Regardless using pagefault_disable() ensures that no matter what locking
implementation is used a deadlock will not occur.
Complete kmap conversion in userfaultfd by replacing the kmap() and
kmap_atomic() calls with kmap_local_page(). When replacing the
kmap_atomic() call ensure page faults continue to be disabled to support
the correct fall back behavior and add a comment to inform future souls of
the requirement.
[1] https://lore.kernel.org/all/20220813220034.806698-1-ira.weiny@intel.com/
[2] https://lore.kernel.org/all/Y1Mh2S7fUGQ%2FiKFR@iweiny-desk3/
[3] https://lore.kernel.org/all/Y1MymJ%2FINb45AdaY@iweiny-desk3/
[4] https://lore.kernel.org/lkml/Y1bXBtGTCym77%2FoD@casper.infradead.org/
[ira.weiny@intel.com: v2]
Link: https://lkml.kernel.org/r/20221025220136.2366143-1-ira.weiny@intel.com
Link: https://lkml.kernel.org/r/20221024043452.1491677-1-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ensure that KMSAN builds replace memset/memcpy/memmove calls with the
respective __msan_XXX functions, and that none of the macros are redefined
twice. This should allow building kernel with both CONFIG_KMSAN and
CONFIG_FORTIFY_SOURCE.
Link: https://lkml.kernel.org/r/20221024212144.2852069-5-glider@google.com
Link: https://github.com/google/kmsan/issues/89
Signed-off-by: Alexander Potapenko <glider@google.com>
Reported-by: Tamas K Lengyel <tamas.lengyel@zentific.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
During THP migration, if THPs are not migrated but they are split and all
subpages are migrated successfully, migrate_pages() will still return the
number of THP pages that were not migrated. This will confuse the callers
of migrate_pages(). For example, the longterm pinning will failed though
all pages are migrated successfully.
Thus we should return 0 to indicate that all pages are migrated in this
case
Link: https://lkml.kernel.org/r/de386aa864be9158d2f3b344091419ea7c38b2f7.1666599848.git.baolin.wang@linux.alibaba.com
Fixes: b5bade978e ("mm: migrate: fix the return value of migrate_pages()")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Although page allocation always clears page->private in the first page or
head page of an allocation, it has never made a point of clearing
page->private in the tails (though 0 is often what is already there).
But now commit 71e2d666ef ("mm/huge_memory: do not clobber swp_entry_t
during THP split") issues a warning when page_tail->private is found to be
non-0 (unless it's swapcache).
Change that warning to dump page_tail (which also dumps head), instead of
just the head: so far we have seen dead000000000122, dead000000000003,
dead000000000001 or 0000000000000002 in the raw output for tail private.
We could just delete the warning, but today's consensus appears to want
page->private to be 0, unless there's a good reason for it to be set: so
now clear it in prep_compound_tail() (more general than just for THP; but
not for high order allocation, which makes no pass down the tails).
Link: https://lkml.kernel.org/r/1c4233bb-4e4d-5969-fbd4-96604268a285@google.com
Fixes: 71e2d666ef ("mm/huge_memory: do not clobber swp_entry_t during THP split")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A common use case for hugetlbfs is for the application to create
memory pools backed by huge pages, which then get handed over to
some malloc library (eg. jemalloc) for further management.
That malloc library may be doing MADV_DONTNEED calls on memory
that is no longer needed, expecting those calls to happen on
PAGE_SIZE boundaries.
However, currently the MADV_DONTNEED code rounds up any such
requests to HPAGE_PMD_SIZE boundaries. This leads to undesired
outcomes when jemalloc expects a 4kB MADV_DONTNEED, but 2MB of
memory get zeroed out, instead.
Use of pre-built shared libraries means that user code does not
always know the page size of every memory arena in use.
Avoid unexpected data loss with MADV_DONTNEED by rounding up
only to PAGE_SIZE (in do_madvise), and rounding down to huge
page granularity.
That way programs will only get as much memory zeroed out as
they requested.
Link: https://lkml.kernel.org/r/20221021192805.366ad573@imladris.surriel.com
Fixes: 90e7e7f5ef ("mm: enable MADV_DONTNEED for hugetlb mappings")
Signed-off-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When !CONFIG_VM_BUG_ON, there is warning of
clang-analyzer-deadcode.DeadStores:
Value stored to 'mt' during its initialization is never read.
Link: https://lkml.kernel.org/r/20221021101555.7992-2-quic_aiquny@quicinc.com
Signed-off-by: Maria Yu <quic_aiquny@quicinc.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In sysfs, we use attribute name "cpumap" or "cpus" for cpu mask and
"cpulist" or "cpus_list" for cpu list. For example, in my system,
$ cat /sys/devices/system/node/node0/cpumap
f,ffffffff
$ cat /sys/devices/system/cpu/cpu2/topology/core_cpus
0,00100004
$ cat cat /sys/devices/system/node/node0/cpulist
0-35
$ cat /sys/devices/system/cpu/cpu2/topology/core_cpus_list
2,20
It looks reasonable to use "nodemap" for node mask and "nodelist" for
node list. So, rename the attribute to follow the naming convention.
Link: https://lkml.kernel.org/r/20221020015122.290097-1-ying.huang@intel.com
Fixes: 9832fb8783 ("mm/demotion: expose memory tier details via sysfs")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Wei Xu <weixugc@google.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Bharata B Rao <bharata@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hesham Almatary <hesham.almatary@huawei.com>
Cc: Jagdish Gediya <jvgediya.oss@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 6edda04ccc ("mm/kmemleak: prevent soft lockup in first object
iteration loop of kmemleak_scan()") adds cond_resched() in the first
object iteration loop of kmemleak_scan(). However, it turns that the 2nd
objection iteration loop can still cause soft lockup to happen in some
cases. So add a cond_resched() call in the 2nd and 3rd loops as well to
prevent that and for completeness.
Link: https://lkml.kernel.org/r/20221020175619.366317-1-longman@redhat.com
Fixes: 6edda04ccc ("mm/kmemleak: prevent soft lockup in first object iteration loop of kmemleak_scan()")
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The following has been observed when running stressng mmap since commit
b653db7735 ("mm: Clear page->private when splitting or migrating a page")
watchdog: BUG: soft lockup - CPU#75 stuck for 26s! [stress-ng:9546]
CPU: 75 PID: 9546 Comm: stress-ng Tainted: G E 6.0.0-revert-b653db77-fix+ #29 0357d79b60fb09775f678e4f3f64ef0579ad1374
Hardware name: SGI.COM C2112-4GP3/X10DRT-P-Series, BIOS 2.0a 05/09/2016
RIP: 0010:xas_descend+0x28/0x80
Code: cc cc 0f b6 0e 48 8b 57 08 48 d3 ea 83 e2 3f 89 d0 48 83 c0 04 48 8b 44 c6 08 48 89 77 18 48 89 c1 83 e1 03 48 83 f9 02 75 08 <48> 3d fd 00 00 00 76 08 88 57 12 c3 cc cc cc cc 48 c1 e8 02 89 c2
RSP: 0018:ffffbbf02a2236a8 EFLAGS: 00000246
RAX: ffff9cab7d6a0002 RBX: ffffe04b0af88040 RCX: 0000000000000002
RDX: 0000000000000030 RSI: ffff9cab60509b60 RDI: ffffbbf02a2236c0
RBP: 0000000000000000 R08: ffff9cab60509b60 R09: ffffbbf02a2236c0
R10: 0000000000000001 R11: ffffbbf02a223698 R12: 0000000000000000
R13: ffff9cab4e28da80 R14: 0000000000039c01 R15: ffff9cab4e28da88
FS: 00007fab89b85e40(0000) GS:ffff9cea3fcc0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fab84e00000 CR3: 00000040b73a4003 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
xas_load+0x3a/0x50
__filemap_get_folio+0x80/0x370
? put_swap_page+0x163/0x360
pagecache_get_page+0x13/0x90
__try_to_reclaim_swap+0x50/0x190
scan_swap_map_slots+0x31e/0x670
get_swap_pages+0x226/0x3c0
folio_alloc_swap+0x1cc/0x240
add_to_swap+0x14/0x70
shrink_page_list+0x968/0xbc0
reclaim_page_list+0x70/0xf0
reclaim_pages+0xdd/0x120
madvise_cold_or_pageout_pte_range+0x814/0xf30
walk_pgd_range+0x637/0xa30
__walk_page_range+0x142/0x170
walk_page_range+0x146/0x170
madvise_pageout+0xb7/0x280
? asm_common_interrupt+0x22/0x40
madvise_vma_behavior+0x3b7/0xac0
? find_vma+0x4a/0x70
? find_vma+0x64/0x70
? madvise_vma_anon_name+0x40/0x40
madvise_walk_vmas+0xa6/0x130
do_madvise+0x2f4/0x360
__x64_sys_madvise+0x26/0x30
do_syscall_64+0x5b/0x80
? do_syscall_64+0x67/0x80
? syscall_exit_to_user_mode+0x17/0x40
? do_syscall_64+0x67/0x80
? syscall_exit_to_user_mode+0x17/0x40
? do_syscall_64+0x67/0x80
? do_syscall_64+0x67/0x80
? common_interrupt+0x8b/0xa0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
The problem can be reproduced with the mmtests config
config-workload-stressng-mmap. It does not always happen and when it
triggers is variable but it has happened on multiple machines.
The intent of commit b653db7735 patch was to avoid the case where
PG_private is clear but folio->private is not-NULL. However, THP tail
pages uses page->private for "swp_entry_t if folio_test_swapcache()" as
stated in the documentation for struct folio. This patch only clobbers
page->private for tail pages if the head page was not in swapcache and
warns once if page->private had an unexpected value.
Link: https://lkml.kernel.org/r/20221019134156.zjyyn5aownakvztf@techsingularity.net
Fixes: b653db7735 ("mm: Clear page->private when splitting or migrating a page")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The hugetlb vma_lock structure hangs off the vm_private_data pointer of
sharable hugetlb vmas. The structure is vma specific and can not be
shared between vmas. At fork and various other times, vmas are duplicated
via vm_area_dup(). When this happens, the pointer in the newly created
vma must be cleared and the structure reallocated. Two hugetlb specific
routines deal with this hugetlb_dup_vma_private and hugetlb_vm_op_open.
Both routines are called for newly created vmas. hugetlb_dup_vma_private
would always clear the pointer and hugetlb_vm_op_open would allocate the
new vms_lock structure. This did not work in the case of this calling
sequence pointed out in [1].
move_vma
copy_vma
new_vma = vm_area_dup(vma);
new_vma->vm_ops->open(new_vma); --> new_vma has its own vma lock.
is_vm_hugetlb_page(vma)
clear_vma_resv_huge_pages
hugetlb_dup_vma_private --> vma->vm_private_data is set to NULL
When clearing hugetlb_dup_vma_private we actually leak the associated
vma_lock structure.
The vma_lock structure contains a pointer to the associated vma. This
information can be used in hugetlb_dup_vma_private and hugetlb_vm_op_open
to ensure we only clear the vm_private_data of newly created (copied)
vmas. In such cases, the vma->vma_lock->vma field will not point to the
vma.
Update hugetlb_dup_vma_private and hugetlb_vm_op_open to not clear
vm_private_data if vma->vma_lock->vma == vma. Also, log a warning if
hugetlb_vm_op_open ever encounters the case where vma_lock has already
been correctly allocated for the vma.
[1] https://lore.kernel.org/linux-mm/5154292a-4c55-28cd-0935-82441e512fc3@huawei.com/
Link: https://lkml.kernel.org/r/20221019201957.34607-1-mike.kravetz@oracle.com
Fixes: 131a79b474 ("hugetlb: fix vma lock handling during split vma and range unmapping")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Try to avoid using the left over split page on the next request for a page
by calling __free_pages_ok() with FPI_TO_TAIL. This increases the
potential of defragmenting memory when it's used for a short period of
time.
Link: https://lkml.kernel.org/r/20220531185626.yvlmymbxyoe5vags@revolver
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The h->*_huge_pages counters are protected by the hugetlb_lock, but
alloc_huge_page has a corner case where it can decrement the counter
outside of the lock.
This could lead to a corrupted value of h->resv_huge_pages, which we have
observed on our systems.
Take the hugetlb_lock before decrementing h->resv_huge_pages to avoid a
potential race.
Link: https://lkml.kernel.org/r/20221017202505.0e6a4fcd@imladris.surriel.com
Fixes: a88c769548 ("mm: hugetlb: fix hugepage memory leak caused by wrong reserve count")
Signed-off-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Glen McCready <gkmccready@meta.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mmap should return the start address of newly mapped area when successful.
On a successful merge of a VMA, the return address was changed and thus
was violating that expectation from userspace.
This is a restoration of functionality provided by 309d08d9b3
(mm/mmap.c: fix mmap return value when vma is merged after call_mmap()).
For completeness of fixing MAP_FIXED, implement the comments from the
previous discussion to never update the address and fail if the address
changes. Leaving the error as a WARN_ON() to avoid crashing the kernel.
Link: https://lkml.kernel.org/r/20221018191613.4133459-1-Liam.Howlett@oracle.com
Link: https://lore.kernel.org/all/Y06yk66SKxlrwwfb@lakrids/
Link: https://lore.kernel.org/all/20201203085350.22624-1-liuzixian4@huawei.com/
Fixes: 4dd1b84140 ("mm/mmap: use advanced maple tree API for mmap_region()")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Mark Rutland <mark.rutland@arm.com>
Cc: Liu Zixian <liuzixian4@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The code is OK, but it fools gcc.
mm/mmap.c:802 __vma_adjust() error: uninitialized symbol 'next_next'.
Fixes: 524e00b36e ("mm: remove rb tree.")
Reported-by: kernel test robot <lkp@intel.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A memory leak in hugetlb_reserve_pages was reported in [1]. The root
cause was traced to an error path in mmap_region when mas_preallocate()
fails. In this case, the vma is freed after a successful call to
filesystem specific mmap. The hugetlbfs mmap routine may allocate data
structures pointed to by m_private_data. These need to be cleaned up by
the hugetlb vm_ops->close() routine.
The same issue was addressed by commit deb0f65628 ("mm/mmap: undo
->mmap() when arch_validate_flags() fails") for the arch_validate_flags()
test. Go to the same close_and_free_vma label if mas_preallocate() fails.
[1] https://lore.kernel.org/linux-mm/CAKXUXMxf7OiCwbxib7MwfR4M1b5+b3cNTU7n5NV9Zm4967=FPQ@mail.gmail.com/
Link: https://lkml.kernel.org/r/20221018024945.415036-1-mike.kravetz@oracle.com
Fixes: d4af56c5c7 ("mm: start tracking VMAs with maple tree")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Inside the zs_destroy_pool() function, there can still be NULL size_class
pointers: if when the next size_class is allocated, inside
zs_create_pool() function, kzalloc will return NULL and handling the error
condition, zs_create_pool() will call zs_destroy_pool().
Link: https://lkml.kernel.org/r/20221013112825.61869-1-avromanov@sberdevices.ru
Fixes: f24263a5a0 ("zsmalloc: remove unnecessary size_class NULL check")
Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Fuzzing produced an invalid argument to vma_merge() which was caught by
the newly added verification of the number of VMAs being removed on
process exit. Analyzing the failure eventually resulted in finding an
issue with the search of a VMA that started at address 0, which caused an
underflow and thus the loss of many VMAs being tracked in the tree. Fix
the underflow by changing the search of the maple tree to use the start
address directly.
Link: https://lkml.kernel.org/r/20221015021135.2816178-1-Liam.Howlett@oracle.com
Fixes: 66850be55e ("mm/mempolicy: use vma iterator & maple state instead of vma linked list")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/r/202210052318.5ad10912-oliver.sang@intel.com
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Merge tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull more random number generator updates from Jason Donenfeld:
"This time with some large scale treewide cleanups.
The intent of this pull is to clean up the way callers fetch random
integers. The current rules for doing this right are:
- If you want a secure or an insecure random u64, use get_random_u64()
- If you want a secure or an insecure random u32, use get_random_u32()
The old function prandom_u32() has been deprecated for a while
now and is just a wrapper around get_random_u32(). Same for
get_random_int().
- If you want a secure or an insecure random u16, use get_random_u16()
- If you want a secure or an insecure random u8, use get_random_u8()
- If you want secure or insecure random bytes, use get_random_bytes().
The old function prandom_bytes() has been deprecated for a while
now and has long been a wrapper around get_random_bytes()
- If you want a non-uniform random u32, u16, or u8 bounded by a
certain open interval maximum, use prandom_u32_max()
I say "non-uniform", because it doesn't do any rejection sampling
or divisions. Hence, it stays within the prandom_*() namespace, not
the get_random_*() namespace.
I'm currently investigating a "uniform" function for 6.2. We'll see
what comes of that.
By applying these rules uniformly, we get several benefits:
- By using prandom_u32_max() with an upper-bound that the compiler
can prove at compile-time is ≤65536 or ≤256, internally
get_random_u16() or get_random_u8() is used, which wastes fewer
batched random bytes, and hence has higher throughput.
- By using prandom_u32_max() instead of %, when the upper-bound is
not a constant, division is still avoided, because
prandom_u32_max() uses a faster multiplication-based trick instead.
- By using get_random_u16() or get_random_u8() in cases where the
return value is intended to indeed be a u16 or a u8, we waste fewer
batched random bytes, and hence have higher throughput.
This series was originally done by hand while I was on an airplane
without Internet. Later, Kees and I worked on retroactively figuring
out what could be done with Coccinelle and what had to be done
manually, and then we split things up based on that.
So while this touches a lot of files, the actual amount of code that's
hand fiddled is comfortably small"
* tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
prandom: remove unused functions
treewide: use get_random_bytes() when possible
treewide: use get_random_u32() when possible
treewide: use get_random_{u8,u16}() when possible, part 2
treewide: use get_random_{u8,u16}() when possible, part 1
treewide: use prandom_u32_max() when possible, part 2
treewide: use prandom_u32_max() when possible, part 1
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Merge tag 'slab-for-6.1-rc1-hotfix' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab hotfix from Vlastimil Babka:
"A single fix for the common-kmalloc series, for warnings on mips and
sparc64 reported by Guenter Roeck"
* tag 'slab-for-6.1-rc1-hotfix' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
mm/slab: use kmalloc_node() for off slab freelist_idx_t array allocation
After commit d6a71648db ("mm/slab: kmalloc: pass requests larger than
order-1 page to page allocator"), SLAB passes large ( > PAGE_SIZE * 2)
requests to buddy like SLUB does.
SLAB has been using kmalloc caches to allocate freelist_idx_t array for
off slab caches. But after the commit, freelist_size can be bigger than
KMALLOC_MAX_CACHE_SIZE.
Instead of using pointer to kmalloc cache, use kmalloc_node() and only
check if the kmalloc cache is off slab during calculate_slab_order().
If freelist_size > KMALLOC_MAX_CACHE_SIZE, no looping condition happens
as it allocates freelist_idx_t array directly from buddy.
Link: https://lore.kernel.org/all/20221014205818.GA1428667@roeck-us.net/
Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Fixes: d6a71648db ("mm/slab: kmalloc: pass requests larger than order-1 page to page allocator")
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
refcounting errors in ZONE_DEVICE pages.
- Peter Xu fixes some userfaultfd test harness instability.
- Various other patches in MM, mainly fixes.
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Merge tag 'mm-stable-2022-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton:
- fix a race which causes page refcounting errors in ZONE_DEVICE pages
(Alistair Popple)
- fix userfaultfd test harness instability (Peter Xu)
- various other patches in MM, mainly fixes
* tag 'mm-stable-2022-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (29 commits)
highmem: fix kmap_to_page() for kmap_local_page() addresses
mm/page_alloc: fix incorrect PGFREE and PGALLOC for high-order page
mm/selftest: uffd: explain the write missing fault check
mm/hugetlb: use hugetlb_pte_stable in migration race check
mm/hugetlb: fix race condition of uffd missing/minor handling
zram: always expose rw_page
LoongArch: update local TLB if PTE entry exists
mm: use update_mmu_tlb() on the second thread
kasan: fix array-bounds warnings in tests
hmm-tests: add test for migrate_device_range()
nouveau/dmem: evict device private memory during release
nouveau/dmem: refactor nouveau_dmem_fault_copy_one()
mm/migrate_device.c: add migrate_device_range()
mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()
mm/memremap.c: take a pgmap reference on page allocation
mm: free device private pages have zero refcount
mm/memory.c: fix race when faulting a device private page
mm/damon: use damon_sz_region() in appropriate place
mm/damon: move sz_damon_region to damon_sz_region
lib/test_meminit: add checks for the allocation functions
...
kmap_to_page() is used to get the page for a virtual address which may
be kmap'ed. Unfortunately, kmap_local_page() stores mappings in a
thread local array separate from kmap(). These mappings were not
checked by the call.
Check the kmap_local_page() mappings and return the page if found.
Because it is intended to remove kmap_to_page() add a warn on once to
the kmap checks to flag potential issues early.
NOTE Due to 32bit x86 use of kmap local in iomap atmoic, KMAP_LOCAL does
not require HIGHMEM to be set. Therefore the support calls required a
new KMAP_LOCAL section to fix 0day build errors.
[akpm@linux-foundation.org: fix warning]
Link: https://lkml.kernel.org/r/20221006040555.1502679-1-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Reported-by: kernel test robot <lkp@intel.com>
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
PGFREE and PGALLOC represent the number of freed and allocated pages. So
the page order must be considered.
Link: https://lkml.kernel.org/r/20221006101540.40686-1-laoar.shao@gmail.com
Fixes: 44042b4498 ("mm/page_alloc: allow high-order pages to be stored on the per-cpu lists")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
After hugetlb_pte_stable() introduced, we can also rewrite the migration
race condition against page allocation to use the new helper too.
Link: https://lkml.kernel.org/r/20221004193400.110155-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/hugetlb: Fix selftest failures with write check", v3.
Currently akpm mm-unstable fails with uffd hugetlb private mapping test
randomly on a write check.
The initial bisection of that points to the recent pmd unshare series, but
it turns out there's no direction relationship with the series but only
some timing change caused the race to start trigger.
The race should be fixed in patch 1. Patch 2 is a trivial cleanup on the
similar race with hugetlb migrations, patch 3 comment on the write check
so when anyone read it again it'll be clear why it's there.
This patch (of 3):
After the recent rework patchset of hugetlb locking on pmd sharing,
kselftest for userfaultfd sometimes fails on hugetlb private tests with
unexpected write fault checks.
It turns out there's nothing wrong within the locking series regarding
this matter, but it could have changed the timing of threads so it can
trigger an old bug.
The real bug is when we call hugetlb_no_page() we're not with the pgtable
lock. It means we're reading the pte values lockless. It's perfectly
fine in most cases because before we do normal page allocations we'll take
the lock and check pte_same() again. However before that, there are
actually two paths on userfaultfd missing/minor handling that may directly
move on with the fault process without checking the pte values.
It means for these two paths we may be generating an uffd message based on
an unstable pte, while an unstable pte can legally be anything as long as
the modifier holds the pgtable lock.
One example, which is also what happened in the failing kselftest and
caused the test failure, is that for private mappings wr-protection
changes can happen on one page. While hugetlb_change_protection()
generally requires pte being cleared before being changed, then there can
be a race condition like:
thread 1 thread 2
-------- --------
UFFDIO_WRITEPROTECT hugetlb_fault
hugetlb_change_protection
pgtable_lock()
huge_ptep_modify_prot_start
pte==NULL
hugetlb_no_page
generate uffd missing event
even if page existed!!
huge_ptep_modify_prot_commit
pgtable_unlock()
Fix this by rechecking the pte after pgtable lock for both userfaultfd
missing & minor fault paths.
This bug should have been around starting from uffd hugetlb introduced, so
attaching a Fixes to the commit. Also attach another Fixes to the minor
support commit for easier tracking.
Note that userfaultfd is actually fine with false positives (e.g. caused
by pte changed), but not wrong logical events (e.g. caused by reading a
pte during changing). The latter can confuse the userspace, so the
strictness is very much preferred. E.g., MISSING event should never
happen on the page after UFFDIO_COPY has correctly installed the page and
returned.
Link: https://lkml.kernel.org/r/20221004193400.110155-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20221004193400.110155-2-peterx@redhat.com
Fixes: 1a1aad8a9b ("userfaultfd: hugetlbfs: add userfaultfd hugetlb hook")
Fixes: 7677f7fd8b ("userfaultfd: add minor fault registration mode")
Signed-off-by: Peter Xu <peterx@redhat.com>
Co-developed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
As message in commit 7df6769743 ("mm/memory.c: Update local TLB if PTE
entry exists") said, we should update local TLB only on the second thread.
So in the do_anonymous_page() here, we should use update_mmu_tlb()
instead of update_mmu_cache() on the second thread.
As David pointed out, this is a performance improvement, not a
correctness fix.
Link: https://lkml.kernel.org/r/20220929112318.32393-2-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: Chris Zankel <chris@zankel.net>
Cc: Huacai Chen <chenhuacai@loongson.cn>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
GCC's -Warray-bounds option detects out-of-bounds accesses to
statically-sized allocations in krealloc out-of-bounds tests.
Use OPTIMIZER_HIDE_VAR to suppress the warning.
Also change kmalloc_memmove_invalid_size to use OPTIMIZER_HIDE_VAR
instead of a volatile variable.
Link: https://lkml.kernel.org/r/e94399242d32e00bba6fd0d9ec4c897f188128e8.1664215688.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Device drivers can use the migrate_vma family of functions to migrate
existing private anonymous mappings to device private pages. These pages
are backed by memory on the device with drivers being responsible for
copying data to and from device memory.
Device private pages are freed via the pgmap->page_free() callback when
they are unmapped and their refcount drops to zero. Alternatively they
may be freed indirectly via migration back to CPU memory in response to a
pgmap->migrate_to_ram() callback called whenever the CPU accesses an
address mapped to a device private page.
In other words drivers cannot control the lifetime of data allocated on
the devices and must wait until these pages are freed from userspace.
This causes issues when memory needs to reclaimed on the device, either
because the device is going away due to a ->release() callback or because
another user needs to use the memory.
Drivers could use the existing migrate_vma functions to migrate data off
the device. However this would require them to track the mappings of each
page which is both complicated and not always possible. Instead drivers
need to be able to migrate device pages directly so they can free up
device memory.
To allow that this patch introduces the migrate_device family of functions
which are functionally similar to migrate_vma but which skips the initial
lookup based on mapping.
Link: https://lkml.kernel.org/r/868116aab70b0c8ee467d62498bb2cf0ef907295.1664366292.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
migrate_device_coherent_page() reuses the existing migrate_vma family of
functions to migrate a specific page without providing a valid mapping or
vma. This looks a bit odd because it means we are calling migrate_vma_*()
without setting a valid vma, however it was considered acceptable at the
time because the details were internal to migrate_device.c and there was
only a single user.
One of the reasons the details could be kept internal was that this was
strictly for migrating device coherent memory. Such memory can be copied
directly by the CPU without intervention from a driver. However this
isn't true for device private memory, and a future change requires similar
functionality for device private memory. So refactor the code into
something more sensible for migrating device memory without a vma.
Link: https://lkml.kernel.org/r/c7b2ff84e9b33d022cf4a40f87d051f281a16d8f.1664366292.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
ZONE_DEVICE pages have a struct dev_pagemap which is allocated by a
driver. When the struct page is first allocated by the kernel in
memremap_pages() a reference is taken on the associated pagemap to ensure
it is not freed prior to the pages being freed.
Prior to 27674ef6c7 ("mm: remove the extra ZONE_DEVICE struct page
refcount") pages were considered free and returned to the driver when the
reference count dropped to one. However the pagemap reference was not
dropped until the page reference count hit zero. This would occur as part
of the final put_page() in memunmap_pages() which would wait for all pages
to be freed prior to returning.
When the extra refcount was removed the pagemap reference was no longer
being dropped in put_page(). Instead memunmap_pages() was changed to
explicitly drop the pagemap references. This means that memunmap_pages()
can complete even though pages are still mapped by the kernel which can
lead to kernel crashes, particularly if a driver frees the pagemap.
To fix this drivers should take a pagemap reference when allocating the
page. This reference can then be returned when the page is freed.
Link: https://lkml.kernel.org/r/12d155ec727935ebfbb4d639a03ab374917ea51b.1664366292.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Fixes: 27674ef6c7 ("mm: remove the extra ZONE_DEVICE struct page refcount")
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since 27674ef6c7 ("mm: remove the extra ZONE_DEVICE struct page
refcount") device private pages have no longer had an extra reference
count when the page is in use. However before handing them back to the
owning device driver we add an extra reference count such that free pages
have a reference count of one.
This makes it difficult to tell if a page is free or not because both free
and in use pages will have a non-zero refcount. Instead we should return
pages to the drivers page allocator with a zero reference count. Kernel
code can then safely use kernel functions such as get_page_unless_zero().
Link: https://lkml.kernel.org/r/cf70cf6f8c0bdb8aaebdbfb0d790aea4c683c3c6.1664366292.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Fix several device private page reference counting issues",
v2
This series aims to fix a number of page reference counting issues in
drivers dealing with device private ZONE_DEVICE pages. These result in
use-after-free type bugs, either from accessing a struct page which no
longer exists because it has been removed or accessing fields within the
struct page which are no longer valid because the page has been freed.
During normal usage it is unlikely these will cause any problems. However
without these fixes it is possible to crash the kernel from userspace.
These crashes can be triggered either by unloading the kernel module or
unbinding the device from the driver prior to a userspace task exiting.
In modules such as Nouveau it is also possible to trigger some of these
issues by explicitly closing the device file-descriptor prior to the task
exiting and then accessing device private memory.
This involves some minor changes to both PowerPC and AMD GPU code.
Unfortunately I lack hardware to test either of those so any help there
would be appreciated. The changes mimic what is done in for both Nouveau
and hmm-tests though so I doubt they will cause problems.
This patch (of 8):
When the CPU tries to access a device private page the migrate_to_ram()
callback associated with the pgmap for the page is called. However no
reference is taken on the faulting page. Therefore a concurrent migration
of the device private page can free the page and possibly the underlying
pgmap. This results in a race which can crash the kernel due to the
migrate_to_ram() function pointer becoming invalid. It also means drivers
can't reliably read the zone_device_data field because the page may have
been freed with memunmap_pages().
Close the race by getting a reference on the page while holding the ptl to
ensure it has not been freed. Unfortunately the elevated reference count
will cause the migration required to handle the fault to fail. To avoid
this failure pass the faulting page into the migrate_vma functions so that
if an elevated reference count is found it can be checked to see if it's
expected or not.
[mpe@ellerman.id.au: fix build]
Link: https://lkml.kernel.org/r/87fsgbf3gh.fsf@mpe.ellerman.id.au
Link: https://lkml.kernel.org/r/cover.60659b549d8509ddecafad4f498ee7f03bb23c69.1664366292.git-series.apopple@nvidia.com
Link: https://lkml.kernel.org/r/d3e813178a59e565e8d78d9b9a4e2562f6494f90.1664366292.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In many places we can use damon_sz_region() to instead of "r->ar.end -
r->ar.start".
Link: https://lkml.kernel.org/r/20220927001946.85375-2-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rename sz_damon_region() to damon_sz_region(), and move it to
"include/linux/damon.h", because in many places, we can to use this func.
Link: https://lkml.kernel.org/r/20220927001946.85375-1-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This is an optimization to reduce stackdepot pressure.
struct mmu_gather contains 7 1-bit fields packed into a 32-bit unsigned
int value. The remaining 25 bits remain uninitialized and are never used,
but KMSAN updates the origin for them in zap_pXX_range() in mm/memory.c,
thus creating very long origin chains. This is technically correct, but
consumes too much memory.
Unpoisoning the whole structure will prevent creating such chains.
Link: https://lkml.kernel.org/r/20220905122452.2258262-20-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit c462ac288f ("mm: Introduce arch_validate_flags()") added a late
check in mmap_region() to let architectures validate vm_flags. The check
needs to happen after calling ->mmap() as the flags can potentially be
modified during this callback.
If arch_validate_flags() check fails we unmap and free the vma. However,
the error path fails to undo the ->mmap() call that previously succeeded
and depending on the specific ->mmap() implementation this translates to
reference increments, memory allocations and other operations what will
not be cleaned up.
There are several places (mainly device drivers) where this is an issue.
However, one specific example is bpf_map_mmap() which keeps count of the
mappings in map->writecnt. The count is incremented on ->mmap() and then
decremented on vm_ops->close(). When arch_validate_flags() fails this
count is off since bpf_map_mmap_close() is never called.
One can reproduce this issue in arm64 devices with MTE support. Here the
vm_flags are checked to only allow VM_MTE if VM_MTE_ALLOWED has been set
previously. From userspace then is enough to pass the PROT_MTE flag to
mmap() syscall to trigger the arch_validate_flags() failure.
The following program reproduces this issue:
#include <stdio.h>
#include <unistd.h>
#include <linux/unistd.h>
#include <linux/bpf.h>
#include <sys/mman.h>
int main(void)
{
union bpf_attr attr = {
.map_type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(long long),
.max_entries = 256,
.map_flags = BPF_F_MMAPABLE,
};
int fd;
fd = syscall(__NR_bpf, BPF_MAP_CREATE, &attr, sizeof(attr));
mmap(NULL, 4096, PROT_WRITE | PROT_MTE, MAP_SHARED, fd, 0);
return 0;
}
By manually adding some log statements to the vm_ops callbacks we can
confirm that when passing PROT_MTE to mmap() the map->writecnt is off upon
->release():
With PROT_MTE flag:
root@debian:~# ./bpf-test
[ 111.263874] bpf_map_write_active_inc: map=9 writecnt=1
[ 111.288763] bpf_map_release: map=9 writecnt=1
Without PROT_MTE flag:
root@debian:~# ./bpf-test
[ 157.816912] bpf_map_write_active_inc: map=10 writecnt=1
[ 157.830442] bpf_map_write_active_dec: map=10 writecnt=0
[ 157.832396] bpf_map_release: map=10 writecnt=0
This patch fixes the above issue by calling vm_ops->close() when the
arch_validate_flags() check fails, after this we can proceed to unmap and
free the vma on the error path.
Link: https://lkml.kernel.org/r/20220930003844.1210987-1-cmllamas@google.com
Fixes: c462ac288f ("mm: Introduce arch_validate_flags()")
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Liam Howlett <liam.howlett@oracle.com>
Cc: Christian Brauner (Microsoft) <brauner@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org> [5.10+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When PTE_MARKER_UFFD_WP not configured, it's still possible to reach pte
marker code and trigger an warning. Add a few CONFIG_PTE_MARKER_UFFD_WP
ifdefs to make sure the code won't be reached when not compiled in.
Link: https://lkml.kernel.org/r/YzeR+R6b4bwBlBHh@x1n
Fixes: b1f9e87686 ("mm/uffd: enable write protection for shmem & hugetlbfs")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: <syzbot+2b9b4f0895be09a6dec3@syzkaller.appspotmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Edward Liaw <edliaw@google.com>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If the brk VMA is the last vma in a maple node and meets the rare criteria
that it can be expanded, then preallocation is necessary to avoid a
potential fs_reclaim circular lock issue on low resources.
At the same time use the actual vma start address (unaligned) when calling
vma_adjust_trans_huge().
Link: https://lkml.kernel.org/r/20221011160624.1253454-1-Liam.Howlett@oracle.com
Fixes: 2e7ce7d354 (mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap())
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The anon vma was not unlinked and the file was not closed in the failure
path when the machine runs out of memory during the maple tree
modification. This caused a memory leak of the anon vma chain and vma
since neither would be freed.
Link: https://lkml.kernel.org/r/20221011203621.1446507-1-Liam.Howlett@oracle.com
Fixes: 524e00b36e ("mm: remove rb tree")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When we successfully find a pageblock in fast_find_migrateblock(), the
block will be set skip-flag through set_pageblock_skip(). However, when
entering isolate_migratepages_block(), the whole pageblock will be skipped
due to the branch 'if (!valid_page && IS_ALIGNED(low_pfn,
pageblock_nr_pages))'. Eventually we will goto isolate_abort and isolate
nothing. That makes fast_find_migrateblock useless.
In this patch, when we find a suitable pageblock in
fast_find_migrateblock, we do noting but let isolate_migratepages_block to
set skip flag to the pageblock after scan it. Normally, we would isolate
some pages from the fast-find block.
I use mmtest/thpscale-madvhugepage test it. Here is the result:
baseline patch
Amean fault-both-1 1331.66 ( 0.00%) 1261.04 * 5.30%*
Amean fault-both-3 1383.95 ( 0.00%) 1191.69 * 13.89%*
Amean fault-both-5 1568.13 ( 0.00%) 1445.20 * 7.84%*
Amean fault-both-7 1819.62 ( 0.00%) 1555.13 * 14.54%*
Amean fault-both-12 1106.96 ( 0.00%) 1149.43 * -3.84%*
Amean fault-both-18 2196.93 ( 0.00%) 1875.77 * 14.62%*
Amean fault-both-24 2642.69 ( 0.00%) 2671.21 * -1.08%*
Amean fault-both-30 2901.89 ( 0.00%) 2857.32 * 1.54%*
Amean fault-both-32 3747.00 ( 0.00%) 3479.23 * 7.15%*
Link: https://lkml.kernel.org/r/20220713062009.597255-1-zhouchuyi@bytedance.com
Fixes: 70b44595ea ("mm, compaction: use free lists to quickly locate a migration source")
Signed-off-by: zhouchuyi <zhouchuyi@bytedance.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
not.
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Merge tag 'mm-hotfixes-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc hotfixes from Andrew Morton:
"Five hotfixes - three for nilfs2, two for MM. For are cc:stable, one
is not"
* tag 'mm-hotfixes-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
nilfs2: fix leak of nilfs_root in case of writer thread creation failure
nilfs2: fix NULL pointer dereference at nilfs_bmap_lookup_at_level()
nilfs2: fix use-after-free bug of struct nilfs_root
mm/damon/core: initialize damon_target->list in damon_new_target()
mm/hugetlb: fix races when looking up a CONT-PTE/PMD size hugetlb page
'struct damon_target' creation function, 'damon_new_target()' is not
initializing its '->list' field, unlike other DAMON structs creator
functions such as 'damon_new_region()'. Normal users of
'damon_new_target()' initializes the field by adding the target to DAMON
context's targets list, but some code could access the uninitialized
field.
This commit avoids the case by initializing the field in
'damon_new_target()'.
Link: https://lkml.kernel.org/r/20221002193130.8227-1-sj@kernel.org
Fixes: f23b8eee18 ("mm/damon/core: implement region-based sampling")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
On some architectures (like ARM64), it can support CONT-PTE/PMD size
hugetlb, which means it can support not only PMD/PUD size hugetlb (2M and
1G), but also CONT-PTE/PMD size(64K and 32M) if a 4K page size specified.
So when looking up a CONT-PTE size hugetlb page by follow_page(), it will
use pte_offset_map_lock() to get the pte entry lock for the CONT-PTE size
hugetlb in follow_page_pte(). However this pte entry lock is incorrect
for the CONT-PTE size hugetlb, since we should use huge_pte_lock() to get
the correct lock, which is mm->page_table_lock.
That means the pte entry of the CONT-PTE size hugetlb under current pte
lock is unstable in follow_page_pte(), we can continue to migrate or
poison the pte entry of the CONT-PTE size hugetlb, which can cause some
potential race issues, even though they are under the 'pte lock'.
For example, suppose thread A is trying to look up a CONT-PTE size hugetlb
page by move_pages() syscall under the lock, however antoher thread B can
migrate the CONT-PTE hugetlb page at the same time, which will cause
thread A to get an incorrect page, if thread A also wants to do page
migration, then data inconsistency error occurs.
Moreover we have the same issue for CONT-PMD size hugetlb in
follow_huge_pmd().
To fix above issues, rename the follow_huge_pmd() as follow_huge_pmd_pte()
to handle PMD and PTE level size hugetlb, which uses huge_pte_lock() to
get the correct pte entry lock to make the pte entry stable.
Mike said:
Support for CONT_PMD/_PTE was added with bb9dd3df8e ("arm64: hugetlb:
refactor find_num_contig()"). Patch series "Support for contiguous pte
hugepages", v4. However, I do not believe these code paths were
executed until migration support was added with 5480280d3f ("arm64/mm:
enable HugeTLB migration for contiguous bit HugeTLB pages") I would go
with 5480280d3f for the Fixes: targe.
Link: https://lkml.kernel.org/r/635f43bdd85ac2615a58405da82b4d33c6e5eb05.1662017562.git.baolin.wang@linux.alibaba.com
Fixes: 5480280d3f ("arm64/mm: enable HugeTLB migration for contiguous bit HugeTLB pages")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The prandom_u32() function has been a deprecated inline wrapper around
get_random_u32() for several releases now, and compiles down to the
exact same code. Replace the deprecated wrapper with a direct call to
the real function. The same also applies to get_random_int(), which is
just a wrapper around get_random_u32(). This was done as a basic find
and replace.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> # for sch_cake
Acked-by: Chuck Lever <chuck.lever@oracle.com> # for nfsd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> # for thunderbolt
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Acked-by: Helge Deller <deller@gmx.de> # for parisc
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:
@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)
@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@
- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);
// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@
((T)get_random_u32()@p & (LITERAL))
// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@
value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))
// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@
- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)
@collapse_ret@
type T;
identifier VAR;
expression E;
@@
{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}
@drop_var@
type T;
identifier VAR;
@@
{
- T VAR;
... when != VAR
}
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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Merge tag 'pull-tmpfile' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs tmpfile updates from Al Viro:
"Miklos' ->tmpfile() signature change; pass an unopened struct file to
it, let it open the damn thing. Allows to add tmpfile support to FUSE"
* tag 'pull-tmpfile' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fuse: implement ->tmpfile()
vfs: open inside ->tmpfile()
vfs: move open right after ->tmpfile()
vfs: make vfs_tmpfile() static
ovl: use vfs_tmpfile_open() helper
cachefiles: use vfs_tmpfile_open() helper
cachefiles: only pass inode to *mark_inode_inuse() helpers
cachefiles: tmpfile error handling cleanup
hugetlbfs: cleanup mknod and tmpfile
vfs: add vfs_tmpfile_open() helper
linux-next for a couple of months without, to my knowledge, any negative
reports (or any positive ones, come to that).
- Also the Maple Tree from Liam R. Howlett. An overlapping range-based
tree for vmas. It it apparently slight more efficient in its own right,
but is mainly targeted at enabling work to reduce mmap_lock contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
(https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com).
This has yet to be addressed due to Liam's unfortunately timed
vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down to
the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support
file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
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Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
linux-next for a couple of months without, to my knowledge, any
negative reports (or any positive ones, come to that).
- Also the Maple Tree from Liam Howlett. An overlapping range-based
tree for vmas. It it apparently slightly more efficient in its own
right, but is mainly targeted at enabling work to reduce mmap_lock
contention.
Liam has identified a number of other tree users in the kernel which
could be beneficially onverted to mapletrees.
Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
at [1]. This has yet to be addressed due to Liam's unfortunately
timed vacation. He is now back and we'll get this fixed up.
- Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
clang-generated instrumentation to detect used-unintialized bugs down
to the single bit level.
KMSAN keeps finding bugs. New ones, as well as the legacy ones.
- Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
memory into THPs.
- Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
support file/shmem-backed pages.
- userfaultfd updates from Axel Rasmussen
- zsmalloc cleanups from Alexey Romanov
- cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
memory-failure
- Huang Ying adds enhancements to NUMA balancing memory tiering mode's
page promotion, with a new way of detecting hot pages.
- memcg updates from Shakeel Butt: charging optimizations and reduced
memory consumption.
- memcg cleanups from Kairui Song.
- memcg fixes and cleanups from Johannes Weiner.
- Vishal Moola provides more folio conversions
- Zhang Yi removed ll_rw_block() :(
- migration enhancements from Peter Xu
- migration error-path bugfixes from Huang Ying
- Aneesh Kumar added ability for a device driver to alter the memory
tiering promotion paths. For optimizations by PMEM drivers, DRM
drivers, etc.
- vma merging improvements from Jakub Matěn.
- NUMA hinting cleanups from David Hildenbrand.
- xu xin added aditional userspace visibility into KSM merging
activity.
- THP & KSM code consolidation from Qi Zheng.
- more folio work from Matthew Wilcox.
- KASAN updates from Andrey Konovalov.
- DAMON cleanups from Kaixu Xia.
- DAMON work from SeongJae Park: fixes, cleanups.
- hugetlb sysfs cleanups from Muchun Song.
- Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]
* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
hugetlb: allocate vma lock for all sharable vmas
hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
hugetlb: fix vma lock handling during split vma and range unmapping
mglru: mm/vmscan.c: fix imprecise comments
mm/mglru: don't sync disk for each aging cycle
mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
mm: memcontrol: use do_memsw_account() in a few more places
mm: memcontrol: deprecate swapaccounting=0 mode
mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
mm/secretmem: remove reduntant return value
mm/hugetlb: add available_huge_pages() func
mm: remove unused inline functions from include/linux/mm_inline.h
selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
selftests/vm: add thp collapse shmem testing
selftests/vm: add thp collapse file and tmpfs testing
selftests/vm: modularize thp collapse memory operations
selftests/vm: dedup THP helpers
mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
mm/madvise: add file and shmem support to MADV_COLLAPSE
...
* cpuset now support isolated cpus.partition type, which will enable dynamic
CPU isolation.
* pids.peak added to remember the max number of pids used.
* Holes in cgroup namespace plugged.
* Internal cleanups.
Note that for-6.1-fixes was pulled into for-6.1 twice. Both were for
follow-up cleanups and each merge commit has details.
Also, 8a693f7766 ("cgroup: Remove CFTYPE_PRESSURE") removes the flag used
by PSI changes in the tip tree and the merged result won't compile due to
the missing flag. Simply removing the struct init lines specifying the flag
is the correct resolution. linux-next already contains the correct fix:
https://lkml.kernel.org/r/20220912161812.072aaa3b@canb.auug.org.au
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Merge tag 'cgroup-for-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
- cpuset now support isolated cpus.partition type, which will enable
dynamic CPU isolation
- pids.peak added to remember the max number of pids used
- holes in cgroup namespace plugged
- internal cleanups
* tag 'cgroup-for-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (25 commits)
cgroup: use strscpy() is more robust and safer
iocost_monitor: reorder BlkgIterator
cgroup: simplify code in cgroup_apply_control
cgroup: Make cgroup_get_from_id() prettier
cgroup/cpuset: remove unreachable code
cgroup: Remove CFTYPE_PRESSURE
cgroup: Improve cftype add/rm error handling
kselftest/cgroup: Add cpuset v2 partition root state test
cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst
cgroup/cpuset: Make partition invalid if cpumask change violates exclusivity rule
cgroup/cpuset: Relocate a code block in validate_change()
cgroup/cpuset: Show invalid partition reason string
cgroup/cpuset: Add a new isolated cpus.partition type
cgroup/cpuset: Relax constraints to partition & cpus changes
cgroup/cpuset: Allow no-task partition to have empty cpuset.cpus.effective
cgroup/cpuset: Miscellaneous cleanups & add helper functions
cgroup/cpuset: Enable update_tasks_cpumask() on top_cpuset
cgroup: add pids.peak interface for pids controller
cgroup: Remove data-race around cgrp_dfl_visible
cgroup: Fix build failure when CONFIG_SHRINKER_DEBUG
...
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Merge tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator updates from Jason Donenfeld:
- Huawei reported that when they updated their kernel from 4.4 to
something much newer, some userspace code they had broke, the culprit
being the accidental removal of O_NONBLOCK from /dev/random way back
in 5.6. It's been gone for over 2 years now and this is the first
we've heard of it, but userspace breakage is userspace breakage, so
O_NONBLOCK is now back.
- Use randomness from hardware RNGs much more often during early boot,
at the same interval that crng reseeds are done, from Dominik.
- A semantic change in hardware RNG throttling, so that the hwrng
framework can properly feed random.c with randomness from hardware
RNGs that aren't specifically marked as creditable.
A related patch coming to you via Herbert's hwrng tree depends on
this one, not to compile, but just to function properly, so you may
want to merge this PULL before that one.
- A fix to clamp credited bits from the interrupts pool to the size of
the pool sample. This is mainly just a theoretical fix, as it'd be
pretty hard to exceed it in practice.
- Oracle reported that InfiniBand TCP latency regressed by around
10-15% after a change a few cycles ago made at the request of the RT
folks, in which we hoisted a somewhat rare operation (1 in 1024
times) out of the hard IRQ handler and into a workqueue, a pretty
common and boring pattern.
It turns out, though, that scheduling a worker from there has
overhead of its own, whereas scheduling a timer on that same CPU for
the next jiffy amortizes better and doesn't incur the same overhead.
I also eliminated a cache miss by moving the work_struct (and
subsequently, the timer_list) to below a critical cache line, so that
the more critical members that are accessed on every hard IRQ aren't
split between two cache lines.
- The boot-time initialization of the RNG has been split into two
approximate phases: what we can accomplish before timekeeping is
possible and what we can accomplish after.
This winds up being useful so that we can use RDRAND to seed the RNG
before CONFIG_SLAB_FREELIST_RANDOM=y systems initialize slabs, in
addition to other early uses of randomness. The effect is that
systems with RDRAND (or a bootloader seed) will never see any
warnings at all when setting CONFIG_WARN_ALL_UNSEEDED_RANDOM=y. And
kfence benefits from getting a better seed of its own.
- Small systems without much entropy sometimes wind up putting some
truncated serial number read from flash into hostname, so contribute
utsname changes to the RNG, without crediting.
- Add smaller batches to serve requests for smaller integers, and make
use of them when people ask for random numbers bounded by a given
compile-time constant. This has positive effects all over the tree,
most notably in networking and kfence.
- The original jitter algorithm intended (I believe) to schedule the
timer for the next jiffy, not the next-next jiffy, yet it used
mod_timer(jiffies + 1), which will fire on the next-next jiffy,
instead of what I believe was intended, mod_timer(jiffies), which
will fire on the next jiffy. So fix that.
- Fix a comment typo, from William.
* tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
random: clear new batches when bringing new CPUs online
random: fix typos in get_random_bytes() comment
random: schedule jitter credit for next jiffy, not in two jiffies
prandom: make use of smaller types in prandom_u32_max
random: add 8-bit and 16-bit batches
utsname: contribute changes to RNG
random: use init_utsname() instead of utsname()
kfence: use better stack hash seed
random: split initialization into early step and later step
random: use expired timer rather than wq for mixing fast pool
random: avoid reading two cache lines on irq randomness
random: clamp credited irq bits to maximum mixed
random: throttle hwrng writes if no entropy is credited
random: use hwgenerator randomness more frequently at early boot
random: restore O_NONBLOCK support
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Merge tag 'slab-for-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab fixes from Vlastimil Babka:
- The "common kmalloc v4" series [1] by Hyeonggon Yoo.
While the plan after LPC is to try again if it's possible to get rid
of SLOB and SLAB (and if any critical aspect of those is not possible
to achieve with SLUB today, modify it accordingly), it will take a
while even in case there are no objections.
Meanwhile this is a nice cleanup and some parts (e.g. to the
tracepoints) will be useful even if we end up with a single slab
implementation in the future:
- Improves the mm/slab_common.c wrappers to allow deleting
duplicated code between SLAB and SLUB.
- Large kmalloc() allocations in SLAB are passed to page allocator
like in SLUB, reducing number of kmalloc caches.
- Removes the {kmem_cache_alloc,kmalloc}_node variants of
tracepoints, node id parameter added to non-_node variants.
- Addition of kmalloc_size_roundup()
The first two patches from a series by Kees Cook [2] that introduce
kmalloc_size_roundup(). This will allow merging of per-subsystem
patches using the new function and ultimately stop (ab)using ksize()
in a way that causes ongoing trouble for debugging functionality and
static checkers.
- Wasted kmalloc() memory tracking in debugfs alloc_traces
A patch from Feng Tang that enhances the existing debugfs
alloc_traces file for kmalloc caches with information about how much
space is wasted by allocations that needs less space than the
particular kmalloc cache provides.
- My series [3] to fix validation races for caches with enabled
debugging:
- By decoupling the debug cache operation more from non-debug
fastpaths, extra locking simplifications were possible and thus
done afterwards.
- Additional cleanup of PREEMPT_RT specific code on top, by Thomas
Gleixner.
- A late fix for slab page leaks caused by the series, by Feng
Tang.
- Smaller fixes and cleanups:
- Unneeded variable removals, by ye xingchen
- A cleanup removing a BUG_ON() in create_unique_id(), by Chao Yu
Link: https://lore.kernel.org/all/20220817101826.236819-1-42.hyeyoo@gmail.com/ [1]
Link: https://lore.kernel.org/all/20220923202822.2667581-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/all/20220823170400.26546-1-vbabka@suse.cz/ [3]
* tag 'slab-for-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (30 commits)
mm/slub: fix a slab missed to be freed problem
slab: Introduce kmalloc_size_roundup()
slab: Remove __malloc attribute from realloc functions
mm/slub: clean up create_unique_id()
mm/slub: enable debugging memory wasting of kmalloc
slub: Make PREEMPT_RT support less convoluted
mm/slub: simplify __cmpxchg_double_slab() and slab_[un]lock()
mm/slub: convert object_map_lock to non-raw spinlock
mm/slub: remove slab_lock() usage for debug operations
mm/slub: restrict sysfs validation to debug caches and make it safe
mm/sl[au]b: check if large object is valid in __ksize()
mm/slab_common: move declaration of __ksize() to mm/slab.h
mm/slab_common: drop kmem_alloc & avoid dereferencing fields when not using
mm/slab_common: unify NUMA and UMA version of tracepoints
mm/sl[au]b: cleanup kmem_cache_alloc[_node]_trace()
mm/sl[au]b: generalize kmalloc subsystem
mm/slub: move free_debug_processing() further
mm/sl[au]b: introduce common alloc/free functions without tracepoint
mm/slab: kmalloc: pass requests larger than order-1 page to page allocator
mm/slab_common: cleanup kmalloc_large()
...
Introduce preempt_[dis|enable_nested() and use it to clean up
various places which have open coded PREEMPT_RT conditionals.
On PREEMPT_RT enabled kernels, spinlocks and rwlocks are neither disabling
preemption nor interrupts. Though there are a few places which depend on
the implicit preemption/interrupt disable of those locks, e.g. seqcount
write sections, per CPU statistics updates etc.
PREEMPT_RT added open coded CONFIG_PREEMPT_RT conditionals to
disable/enable preemption in the related code parts all over the
place. That's hard to read and does not really explain why this is
necessary.
Linus suggested to use helper functions (preempt_disable_nested() and
preempt_enable_nested()) and use those in the affected places. On !RT
enabled kernels these functions are NOPs, but contain a lockdep assert to
validate that preemption is actually disabled to catch call sites which
do not have preemption disabled.
Clean up the affected code paths in mm, dentry and lib.
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Merge tag 'sched-rt-2022-10-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull preempt RT updates from Thomas Gleixner:
"Introduce preempt_[dis|enable_nested() and use it to clean up various
places which have open coded PREEMPT_RT conditionals.
On PREEMPT_RT enabled kernels, spinlocks and rwlocks are neither
disabling preemption nor interrupts. Though there are a few places
which depend on the implicit preemption/interrupt disable of those
locks, e.g. seqcount write sections, per CPU statistics updates etc.
PREEMPT_RT added open coded CONFIG_PREEMPT_RT conditionals to
disable/enable preemption in the related code parts all over the
place. That's hard to read and does not really explain why this is
necessary.
Linus suggested to use helper functions (preempt_disable_nested() and
preempt_enable_nested()) and use those in the affected places. On !RT
enabled kernels these functions are NOPs, but contain a lockdep assert
to validate that preemption is actually disabled to catch call sites
which do not have preemption disabled.
Clean up the affected code paths in mm, dentry and lib"
* tag 'sched-rt-2022-10-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
u64_stats: Streamline the implementation
flex_proportions: Disable preemption entering the write section.
mm/compaction: Get rid of RT ifdeffery
mm/memcontrol: Replace the PREEMPT_RT conditionals
mm/debug: Provide VM_WARN_ON_IRQS_ENABLED()
mm/vmstat: Use preempt_[dis|en]able_nested()
dentry: Use preempt_[dis|en]able_nested()
preempt: Provide preempt_[dis|en]able_nested()
- Debuggability:
- Change most occurances of BUG_ON() to WARN_ON_ONCE()
- Reorganize & fix TASK_ state comparisons, turn it into a bitmap
- Update/fix misc scheduler debugging facilities
- Load-balancing & regular scheduling:
- Improve the behavior of the scheduler in presence of lot of
SCHED_IDLE tasks - in particular they should not impact other
scheduling classes.
- Optimize task load tracking, cleanups & fixes
- Clean up & simplify misc load-balancing code
- Freezer:
- Rewrite the core freezer to behave better wrt thawing and be simpler
in general, by replacing PF_FROZEN with TASK_FROZEN & fixing/adjusting
all the fallout.
- Deadline scheduler:
- Fix the DL capacity-aware code
- Factor out dl_task_is_earliest_deadline() & replenish_dl_new_period()
- Relax/optimize locking in task_non_contending()
- Cleanups:
- Factor out the update_current_exec_runtime() helper
- Various cleanups, simplifications
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"Debuggability:
- Change most occurances of BUG_ON() to WARN_ON_ONCE()
- Reorganize & fix TASK_ state comparisons, turn it into a bitmap
- Update/fix misc scheduler debugging facilities
Load-balancing & regular scheduling:
- Improve the behavior of the scheduler in presence of lot of
SCHED_IDLE tasks - in particular they should not impact other
scheduling classes.
- Optimize task load tracking, cleanups & fixes
- Clean up & simplify misc load-balancing code
Freezer:
- Rewrite the core freezer to behave better wrt thawing and be
simpler in general, by replacing PF_FROZEN with TASK_FROZEN &
fixing/adjusting all the fallout.
Deadline scheduler:
- Fix the DL capacity-aware code
- Factor out dl_task_is_earliest_deadline() &
replenish_dl_new_period()
- Relax/optimize locking in task_non_contending()
Cleanups:
- Factor out the update_current_exec_runtime() helper
- Various cleanups, simplifications"
* tag 'sched-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
sched: Fix more TASK_state comparisons
sched: Fix TASK_state comparisons
sched/fair: Move call to list_last_entry() in detach_tasks
sched/fair: Cleanup loop_max and loop_break
sched/fair: Make sure to try to detach at least one movable task
sched: Show PF_flag holes
freezer,sched: Rewrite core freezer logic
sched: Widen TAKS_state literals
sched/wait: Add wait_event_state()
sched/completion: Add wait_for_completion_state()
sched: Add TASK_ANY for wait_task_inactive()
sched: Change wait_task_inactive()s match_state
freezer,umh: Clean up freezer/initrd interaction
freezer: Have {,un}lock_system_sleep() save/restore flags
sched: Rename task_running() to task_on_cpu()
sched/fair: Cleanup for SIS_PROP
sched/fair: Default to false in test_idle_cores()
sched/fair: Remove useless check in select_idle_core()
sched/fair: Avoid double search on same cpu
sched/fair: Remove redundant check in select_idle_smt()
...
am sending out early due to me travelling next week. There is a
lone mm patch for which Andrew gave an informal ack at
https://lore.kernel.org/linux-mm/20220817102500.440c6d0a3fce296fdf91bea6@linux-foundation.org.
I will send the bulk of ARM work, as well as other
architectures, at the end of next week.
ARM:
* Account stage2 page table allocations in memory stats.
x86:
* Account EPT/NPT arm64 page table allocations in memory stats.
* Tracepoint cleanups/fixes for nested VM-Enter and emulated MSR accesses.
* Drop eVMCS controls filtering for KVM on Hyper-V, all known versions of
Hyper-V now support eVMCS fields associated with features that are
enumerated to the guest.
* Use KVM's sanitized VMCS config as the basis for the values of nested VMX
capabilities MSRs.
* A myriad event/exception fixes and cleanups. Most notably, pending
exceptions morph into VM-Exits earlier, as soon as the exception is
queued, instead of waiting until the next vmentry. This fixed
a longstanding issue where the exceptions would incorrecly become
double-faults instead of triggering a vmexit; the common case of
page-fault vmexits had a special workaround, but now it's fixed
for good.
* A handful of fixes for memory leaks in error paths.
* Cleanups for VMREAD trampoline and VMX's VM-Exit assembly flow.
* Never write to memory from non-sleepable kvm_vcpu_check_block()
* Selftests refinements and cleanups.
* Misc typo cleanups.
Generic:
* remove KVM_REQ_UNHALT
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"The first batch of KVM patches, mostly covering x86.
ARM:
- Account stage2 page table allocations in memory stats
x86:
- Account EPT/NPT arm64 page table allocations in memory stats
- Tracepoint cleanups/fixes for nested VM-Enter and emulated MSR
accesses
- Drop eVMCS controls filtering for KVM on Hyper-V, all known
versions of Hyper-V now support eVMCS fields associated with
features that are enumerated to the guest
- Use KVM's sanitized VMCS config as the basis for the values of
nested VMX capabilities MSRs
- A myriad event/exception fixes and cleanups. Most notably, pending
exceptions morph into VM-Exits earlier, as soon as the exception is
queued, instead of waiting until the next vmentry. This fixed a
longstanding issue where the exceptions would incorrecly become
double-faults instead of triggering a vmexit; the common case of
page-fault vmexits had a special workaround, but now it's fixed for
good
- A handful of fixes for memory leaks in error paths
- Cleanups for VMREAD trampoline and VMX's VM-Exit assembly flow
- Never write to memory from non-sleepable kvm_vcpu_check_block()
- Selftests refinements and cleanups
- Misc typo cleanups
Generic:
- remove KVM_REQ_UNHALT"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (94 commits)
KVM: remove KVM_REQ_UNHALT
KVM: mips, x86: do not rely on KVM_REQ_UNHALT
KVM: x86: never write to memory from kvm_vcpu_check_block()
KVM: x86: Don't snapshot pending INIT/SIPI prior to checking nested events
KVM: nVMX: Make event request on VMXOFF iff INIT/SIPI is pending
KVM: nVMX: Make an event request if INIT or SIPI is pending on VM-Enter
KVM: SVM: Make an event request if INIT or SIPI is pending when GIF is set
KVM: x86: lapic does not have to process INIT if it is blocked
KVM: x86: Rename kvm_apic_has_events() to make it INIT/SIPI specific
KVM: x86: Rename and expose helper to detect if INIT/SIPI are allowed
KVM: nVMX: Make an event request when pending an MTF nested VM-Exit
KVM: x86: make vendor code check for all nested events
mailmap: Update Oliver's email address
KVM: x86: Allow force_emulation_prefix to be written without a reload
KVM: selftests: Add an x86-only test to verify nested exception queueing
KVM: selftests: Use uapi header to get VMX and SVM exit reasons/codes
KVM: x86: Rename inject_pending_events() to kvm_check_and_inject_events()
KVM: VMX: Update MTF and ICEBP comments to document KVM's subtle behavior
KVM: x86: Treat pending TRIPLE_FAULT requests as pending exceptions
KVM: x86: Morph pending exceptions to pending VM-Exits at queue time
...
The hugetlb vma lock was originally designed to synchronize pmd sharing.
As such, it was only necessary to allocate the lock for vmas that were
capable of pmd sharing. Later in the development cycle, it was discovered
that it could also be used to simplify fault/truncation races as described
in [1]. However, a subsequent change to allocate the lock for all vmas
that use the page cache was never made. A fault/truncation race could
leave pages in a file past i_size until the file is removed.
Remove the previous restriction and allocate lock for all VM_MAYSHARE
vmas. Warn in the unlikely event of allocation failure.
[1] https://lore.kernel.org/lkml/Yxiv0SkMkZ0JWGGp@monkey/#t
Link: https://lkml.kernel.org/r/20221005011707.514612-4-mike.kravetz@oracle.com
Fixes: "hugetlb: clean up code checking for fault/truncation races"
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
hugetlb file truncation/hole punch code may need to back out and take
locks in order in the routine hugetlb_unmap_file_folio(). This code could
race with vma freeing as pointed out in [1] and result in accessing a
stale vma pointer. To address this, take the vma_lock when clearing the
vma_lock->vma pointer.
[1] https://lore.kernel.org/linux-mm/01f10195-7088-4462-6def-909549c75ef4@huawei.com/
[mike.kravetz@oracle.com: address build issues]
Link: https://lkml.kernel.org/r/Yz5L1uxQYR1VqFtJ@monkey
Link: https://lkml.kernel.org/r/20221005011707.514612-3-mike.kravetz@oracle.com
Fixes: "hugetlb: use new vma_lock for pmd sharing synchronization"
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "hugetlb: fixes for new vma lock series".
In review of the series "hugetlb: Use new vma lock for huge pmd sharing
synchronization", Miaohe Lin pointed out two key issues:
1) There is a race in the routine hugetlb_unmap_file_folio when locks
are dropped and reacquired in the correct order [1].
2) With the switch to using vma lock for fault/truncate synchronization,
we need to make sure lock exists for all VM_MAYSHARE vmas, not just
vmas capable of pmd sharing.
These two issues are addressed here. In addition, having a vma lock
present in all VM_MAYSHARE vmas, uncovered some issues around vma
splitting. Those are also addressed.
[1] https://lore.kernel.org/linux-mm/01f10195-7088-4462-6def-909549c75ef4@huawei.com/
This patch (of 3):
The hugetlb vma lock hangs off the vm_private_data field and is specific
to the vma. When vm_area_dup() is called as part of vma splitting, the
vma lock pointer is copied to the new vma. This will result in issues
such as double freeing of the structure. Update the hugetlb open vm_ops
to allocate a new vma lock for the new vma.
The routine __unmap_hugepage_range_final unconditionally unset VM_MAYSHARE
to prevent subsequent pmd sharing. hugetlb_vma_lock_free attempted to
anticipate this by checking both VM_MAYSHARE and VM_SHARED. However, if
only VM_MAYSHARE was set we would miss the free. With the introduction of
the vma lock, a vma can not participate in pmd sharing if vm_private_data
is NULL. Instead of clearing VM_MAYSHARE in __unmap_hugepage_range_final,
free the vma lock to prevent sharing. Also, update the sharing code to
make sure vma lock is indeed a condition for pmd sharing.
hugetlb_vma_lock_free can then key off VM_MAYSHARE and not miss any vmas.
Link: https://lkml.kernel.org/r/20221005011707.514612-1-mike.kravetz@oracle.com
Link: https://lkml.kernel.org/r/20221005011707.514612-2-mike.kravetz@oracle.com
Fixes: "hugetlb: add vma based lock for pmd sharing"
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
wakeup_flusher_threads() was added under the assumption that if a system
runs out of clean cold pages, it might want to write back dirty pages more
aggressively so that they can become clean and be dropped.
However, doing so can breach the rate limit a system wants to impose on
writeback, resulting in early SSD wearout.
Link: https://lkml.kernel.org/r/YzSiWq9UEER5LKup@google.com
Fixes: bd74fdaea1 ("mm: multi-gen LRU: support page table walks")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: Axel Rasmussen <axelrasmussen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Merge tag 'for-6.1/block-2022-10-03' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- NVMe pull requests via Christoph:
- handle number of queue changes in the TCP and RDMA drivers
(Daniel Wagner)
- allow changing the number of queues in nvmet (Daniel Wagner)
- also consider host_iface when checking ip options (Daniel
Wagner)
- don't map pages which can't come from HIGHMEM (Fabio M. De
Francesco)
- avoid unnecessary flush bios in nvmet (Guixin Liu)
- shrink and better pack the nvme_iod structure (Keith Busch)
- add comment for unaligned "fake" nqn (Linjun Bao)
- print actual source IP address through sysfs "address" attr
(Martin Belanger)
- various cleanups (Jackie Liu, Wolfram Sang, Genjian Zhang)
- handle effects after freeing the request (Keith Busch)
- copy firmware_rev on each init (Keith Busch)
- restrict management ioctls to admin (Keith Busch)
- ensure subsystem reset is single threaded (Keith Busch)
- report the actual number of tagset maps in nvme-pci (Keith
Busch)
- small fabrics authentication fixups (Christoph Hellwig)
- add common code for tagset allocation and freeing (Christoph
Hellwig)
- stop using the request_queue in nvmet (Christoph Hellwig)
- set min_align_mask before calculating max_hw_sectors (Rishabh
Bhatnagar)
- send a rediscover uevent when a persistent discovery controller
reconnects (Sagi Grimberg)
- misc nvmet-tcp fixes (Varun Prakash, zhenwei pi)
- MD pull request via Song:
- Various raid5 fix and clean up, by Logan Gunthorpe and David
Sloan.
- Raid10 performance optimization, by Yu Kuai.
- sbitmap wakeup hang fixes (Hugh, Keith, Jan, Yu)
- IO scheduler switching quisce fix (Keith)
- s390/dasd block driver updates (Stefan)
- support for recovery for the ublk driver (ZiyangZhang)
- rnbd drivers fixes and updates (Guoqing, Santosh, ye, Christoph)
- blk-mq and null_blk map fixes (Bart)
- various bcache fixes (Coly, Jilin, Jules)
- nbd signal hang fix (Shigeru)
- block writeback throttling fix (Yu)
- optimize the passthrough mapping handling (me)
- prepare block cgroups to being gendisk based (Christoph)
- get rid of an old PSI hack in the block layer, moving it to the
callers instead where it belongs (Christoph)
- blk-throttle fixes and cleanups (Yu)
- misc fixes and cleanups (Liu Shixin, Liu Song, Miaohe, Pankaj,
Ping-Xiang, Wolfram, Saurabh, Li Jinlin, Li Lei, Lin, Li zeming,
Miaohe, Bart, Coly, Gaosheng
* tag 'for-6.1/block-2022-10-03' of git://git.kernel.dk/linux: (162 commits)
sbitmap: fix lockup while swapping
block: add rationale for not using blk_mq_plug() when applicable
block: adapt blk_mq_plug() to not plug for writes that require a zone lock
s390/dasd: use blk_mq_alloc_disk
blk-cgroup: don't update the blkg lookup hint in blkg_conf_prep
nvmet: don't look at the request_queue in nvmet_bdev_set_limits
nvmet: don't look at the request_queue in nvmet_bdev_zone_mgmt_emulate_all
blk-mq: use quiesced elevator switch when reinitializing queues
block: replace blk_queue_nowait with bdev_nowait
nvme: remove nvme_ctrl_init_connect_q
nvme-loop: use the tagset alloc/free helpers
nvme-loop: store the generic nvme_ctrl in set->driver_data
nvme-loop: initialize sqsize later
nvme-fc: use the tagset alloc/free helpers
nvme-fc: store the generic nvme_ctrl in set->driver_data
nvme-fc: keep ctrl->sqsize in sync with opts->queue_size
nvme-rdma: use the tagset alloc/free helpers
nvme-rdma: store the generic nvme_ctrl in set->driver_data
nvme-tcp: use the tagset alloc/free helpers
nvme-tcp: store the generic nvme_ctrl in set->driver_data
...
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Merge tag 'for-6.1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"There's a bunch of performance improvements, most notably the FIEMAP
speedup, the new block group tree to speed up mount on large
filesystems, more io_uring integration, some sysfs exports and the
usual fixes and core updates.
Summary:
Performance:
- outstanding FIEMAP speed improvement
- algorithmic change how extents are enumerated leads to orders of
magnitude speed boost (uncached and cached)
- extent sharing check speedup (2.2x uncached, 3x cached)
- add more cancellation points, allowing to interrupt seeking in
files with large number of extents
- more efficient hole and data seeking (4x uncached, 1.3x cached)
- sample results:
256M, 32K extents: 4s -> 29ms (~150x)
512M, 64K extents: 30s -> 59ms (~550x)
1G, 128K extents: 225s -> 120ms (~1800x)
- improved inode logging, especially for directories (on dbench
workload throughput +25%, max latency -21%)
- improved buffered IO, remove redundant extent state tracking,
lowering memory consumption and avoiding rb tree traversal
- add sysfs tunable to let qgroup temporarily skip exact accounting
when deleting snapshot, leading to a speedup but requiring a rescan
after that, will be used by snapper
- support io_uring and buffered writes, until now it was just for
direct IO, with the no-wait semantics implemented in the buffered
write path it now works and leads to speed improvement in IOPS
(2x), throughput (2.2x), latency (depends, 2x to 150x)
- small performance improvements when dropping and searching for
extent maps as well as when flushing delalloc in COW mode
(throughput +5MB/s)
User visible changes:
- new incompatible feature block-group-tree adding a dedicated tree
for tracking block groups, this allows a much faster load during
mount and avoids seeking unlike when it's scattered in the extent
tree items
- this reduces mount time for many-terabyte sized filesystems
- conversion tool will be provided so existing filesystem can also
be updated in place
- to reduce test matrix and feature combinations requires no-holes
and free-space-tree (mkfs defaults since 5.15)
- improved reporting of super block corruption detected by scrub
- scrub also tries to repair super block and does not wait until next
commit
- discard stats and tunables are exported in sysfs
(/sys/fs/btrfs/FSID/discard)
- qgroup status is exported in sysfs
(/sys/sys/fs/btrfs/FSID/qgroups/)
- verify that super block was not modified when thawing filesystem
Fixes:
- FIEMAP fixes
- fix extent sharing status, does not depend on the cached status
where merged
- flush delalloc so compressed extents are reported correctly
- fix alignment of VMA for memory mapped files on THP
- send: fix failures when processing inodes with no links (orphan
files and directories)
- fix race between quota enable and quota rescan ioctl
- handle more corner cases for read-only compat feature verification
- fix missed extent on fsync after dropping extent maps
Core:
- lockdep annotations to validate various transactions states and
state transitions
- preliminary support for fs-verity in send
- more effective memory use in scrub for subpage where sector is
smaller than page
- block group caching progress logic has been removed, load is now
synchronous
- simplify end IO callbacks and bio handling, use chained bios
instead of own tracking
- add no-wait semantics to several functions (tree search, nocow,
flushing, buffered write
- cleanups and refactoring
MM changes:
- export balance_dirty_pages_ratelimited_flags"
* tag 'for-6.1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (177 commits)
btrfs: set generation before calling btrfs_clean_tree_block in btrfs_init_new_buffer
btrfs: drop extent map range more efficiently
btrfs: avoid pointless extent map tree search when flushing delalloc
btrfs: remove unnecessary next extent map search
btrfs: remove unnecessary NULL pointer checks when searching extent maps
btrfs: assert tree is locked when clearing extent map from logging
btrfs: remove unnecessary extent map initializations
btrfs: remove the refcount warning/check at free_extent_map()
btrfs: add helper to replace extent map range with a new extent map
btrfs: move open coded extent map tree deletion out of inode eviction
btrfs: use cond_resched_rwlock_write() during inode eviction
btrfs: use extent_map_end() at btrfs_drop_extent_map_range()
btrfs: move btrfs_drop_extent_cache() to extent_map.c
btrfs: fix missed extent on fsync after dropping extent maps
btrfs: remove stale prototype of btrfs_write_inode
btrfs: enable nowait async buffered writes
btrfs: assert nowait mode is not used for some btree search functions
btrfs: make btrfs_buffered_write nowait compatible
btrfs: plumb NOWAIT through the write path
btrfs: make lock_and_cleanup_extent_if_need nowait compatible
...
Since 2d1c498072 ("mm: memcontrol: make swap tracking an integral part
of memory control"), CONFIG_MEMCG_SWAP hasn't been a user-visible config
option anymore, it just means CONFIG_MEMCG && CONFIG_SWAP.
Update the sites accordingly and drop the symbol.
[ While touching the docs, remove two references to CONFIG_MEMCG_KMEM,
which hasn't been a user-visible symbol for over half a decade. ]
Link: https://lkml.kernel.org/r/20220926135704.400818-5-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It's slightly more descriptive and consistent with other places that
distinguish cgroup1's combined memory+swap accounting scheme from
cgroup2's dedicated swap accounting.
Link: https://lkml.kernel.org/r/20220926135704.400818-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The swapaccounting= commandline option already does very little today. To
close a trivial containment failure case, the swap ownership tracking part
of the swap controller has recently become mandatory (see commit
2d1c498072 ("mm: memcontrol: make swap tracking an integral part of
memory control") for details), which makes up the majority of the work
during swapout, swapin, and the swap slot map.
The only thing left under this flag is the page_counter operations and the
visibility of the swap control files in the first place, which are rather
meager savings. There also aren't many scenarios, if any, where
controlling the memory of a cgroup while allowing it unlimited access to a
global swap space is a workable resource isolation strategy.
On the other hand, there have been several bugs and confusion around the
many possible swap controller states (cgroup1 vs cgroup2 behavior, memory
accounting without swap accounting, memcg runtime disabled).
This puts the maintenance overhead of retaining the toggle above its
practical benefits. Deprecate it.
Link: https://lkml.kernel.org/r/20220926135704.400818-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "memcg swap fix & cleanups".
This patch (of 4):
Since commit 2d1c498072 ("mm: memcontrol: make swap tracking an integral
part of memory control"), the cgroup swap arrays are used to track memory
ownership at the time of swap readahead and swapoff, even if swap space
*accounting* has been turned off by the user via swapaccount=0 (which sets
cgroup_memory_noswap).
However, the patch was overzealous: by simply dropping the
cgroup_memory_noswap conditionals in the swapon, swapoff and uncharge
path, it caused the cgroup arrays being allocated even when the memory
controller as a whole is disabled. This is a waste of that memory.
Restore mem_cgroup_disabled() checks, implied previously by
cgroup_memory_noswap, in the swapon, swapoff, and swap_entry_free
callbacks.
Link: https://lkml.kernel.org/r/20220926135704.400818-1-hannes@cmpxchg.org
Link: https://lkml.kernel.org/r/20220926135704.400818-2-hannes@cmpxchg.org
Fixes: 2d1c498072 ("mm: memcontrol: make swap tracking an integral part of memory control")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In hugetlb.c there are several places which compare the values of
'h->free_huge_pages' and 'h->resv_huge_pages', it looks a bit messy, so
add a new available_huge_pages() function to do these.
Link: https://lkml.kernel.org/r/20220922021929.98961-1-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add huge_memory:trace_mm_khugepaged_scan_file tracepoint to
hpage_collapse_scan_file() analogously to hpage_collapse_scan_pmd().
While this change is targeted at debugging MADV_COLLAPSE pathway, the
"mm_khugepaged" prefix is retained for symmetry with
huge_memory:trace_mm_khugepaged_scan_pmd, which retains it's legacy name
to prevent changing kernel ABI as much as possible.
Link: https://lkml.kernel.org/r/20220907144521.3115321-5-zokeefe@google.com
Link: https://lkml.kernel.org/r/20220922224046.1143204-5-zokeefe@google.com
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add support for MADV_COLLAPSE to collapse shmem-backed and file-backed
memory into THPs (requires CONFIG_READ_ONLY_THP_FOR_FS=y).
On success, the backing memory will be a hugepage. For the memory range
and process provided, the page tables will synchronously have a huge pmd
installed, mapping the THP. Other mappings of the file extent mapped by
the memory range may be added to a set of entries that khugepaged will
later process and attempt update their page tables to map the THP by a
pmd.
This functionality unlocks two important uses:
(1) Immediately back executable text by THPs. Current support provided
by CONFIG_READ_ONLY_THP_FOR_FS may take a long time on a large
system which might impair services from serving at their full rated
load after (re)starting. Tricks like mremap(2)'ing text onto
anonymous memory to immediately realize iTLB performance prevents
page sharing and demand paging, both of which increase steady state
memory footprint. Now, we can have the best of both worlds: Peak
upfront performance and lower RAM footprints.
(2) userfaultfd-based live migration of virtual machines satisfy UFFD
faults by fetching native-sized pages over the network (to avoid
latency of transferring an entire hugepage). However, after guest
memory has been fully copied to the new host, MADV_COLLAPSE can
be used to immediately increase guest performance.
Since khugepaged is single threaded, this change now introduces
possibility of collapse contexts racing in file collapse path. There a
important few places to consider:
(1) hpage_collapse_scan_file(), when we xas_pause() and drop RCU.
We could have the memory collapsed out from under us, but
the next xas_for_each() iteration will correctly pick up the
hugepage. The hugepage might not be up to date (insofar as
copying of small page contents might not have completed - the
page still may be locked), but regardless what small page index
we were iterating over, we'll find the hugepage and identify it
as a suitably aligned compound page of order HPAGE_PMD_ORDER.
In khugepaged path, we locklessly check the value of the pmd,
and only add it to deferred collapse array if we find pmd
mapping pte table. This is fine, since other values that could
have raced in right afterwards denote failure, or that the
memory was successfully collapsed, so we don't need further
processing.
In madvise path, we'll take mmap_lock() in write to serialize
against page table updates and will know what to do based on the
true value of the pmd: recheck all ptes if we point to a pte table,
directly install the pmd, if the pmd has been cleared, but
memory not yet faulted, or nothing at all if we find a huge pmd.
It's worth putting emphasis here on how we treat the none pmd
here. If khugepaged has processed this mm's page tables
already, it will have left the pmd cleared (ready for refault by
the process). Depending on the VMA flags and sysfs settings,
amount of RAM on the machine, and the current load, could be a
relatively common occurrence - and as such is one we'd like to
handle successfully in MADV_COLLAPSE. When we see the none pmd
in collapse_pte_mapped_thp(), we've locked mmap_lock in write
and checked (a) huepaged_vma_check() to see if the backing
memory is appropriate still, along with VMA sizing and
appropriate hugepage alignment within the file, and (b) we've
found a hugepage head of order HPAGE_PMD_ORDER at the offset
in the file mapped by our hugepage-aligned virtual address.
Even though the common-case is likely race with khugepaged,
given these checks (regardless how we got here - we could be
operating on a completely different file than originally checked
in hpage_collapse_scan_file() for all we know) it should be safe
to directly make the pmd a huge pmd pointing to this hugepage.
(2) collapse_file() is mostly serialized on the same file extent by
lock sequence:
| lock hupepage
| lock mapping->i_pages
| lock 1st page
| unlock mapping->i_pages
| <page checks>
| lock mapping->i_pages
| page_ref_freeze(3)
| xas_store(hugepage)
| unlock mapping->i_pages
| page_ref_unfreeze(1)
| unlock 1st page
V unlock hugepage
Once a context (who already has their fresh hugepage locked)
locks mapping->i_pages exclusively, it will hold said lock
until it locks the first page, and it will hold that lock until
the after the hugepage has been added to the page cache (and
will unlock the hugepage after page table update, though that
isn't important here).
A racing context that loses the race for mapping->i_pages will
then lose the race to locking the first page. Here - depending
on how far the other racing context has gotten - we might find
the new hugepage (in which case we'll exit cleanly when we
check PageTransCompound()), or we'll find the "old" 1st small
page (in which we'll exit cleanly when we discover unexpected
refcount of 2 after isolate_lru_page()). This is assuming we
are able to successfully lock the page we find - in shmem path,
we could just fail the trylock and exit cleanly anyways.
Failure path in collapse_file() is similar: once we hold lock
on 1st small page, we are serialized against other collapse
contexts. Before the 1st small page is unlocked, we add it
back to the pagecache and unfreeze the refcount appropriately.
Contexts who lost the race to the 1st small page will then find
the same 1st small page with the correct refcount and will be
able to proceed.
[zokeefe@google.com: don't check pmd value twice in collapse_pte_mapped_thp()]
Link: https://lkml.kernel.org/r/20220927033854.477018-1-zokeefe@google.com
[shy828301@gmail.com: Delete hugepage_vma_revalidate_anon(), remove
check for multi-add in khugepaged_add_pte_mapped_thp()]
Link: https://lore.kernel.org/linux-mm/CAHbLzkrtpM=ic7cYAHcqkubah5VTR8N5=k5RT8MTvv5rN1Y91w@mail.gmail.com/
Link: https://lkml.kernel.org/r/20220907144521.3115321-4-zokeefe@google.com
Link: https://lkml.kernel.org/r/20220922224046.1143204-4-zokeefe@google.com
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The main benefit of THPs are that they can be mapped at the pmd level,
increasing the likelihood of TLB hit and spending less cycles in page
table walks. pte-mapped hugepages - that is - hugepage-aligned compound
pages of order HPAGE_PMD_ORDER mapped by ptes - although being contiguous
in physical memory, don't have this advantage. In fact, one could argue
they are detrimental to system performance overall since they occupy a
precious hugepage-aligned/sized region of physical memory that could
otherwise be used more effectively. Additionally, pte-mapped hugepages
can be the cheapest memory to collapse for khugepaged since no new
hugepage allocation or copying of memory contents is necessary - we only
need to update the mapping page tables.
In the anonymous collapse path, we are able to collapse pte-mapped
hugepages (albeit, perhaps suboptimally), but the file/shmem path makes no
effort when compound pages (of any order) are encountered.
Identify pte-mapped hugepages in the file/shmem collapse path. The
final step of which makes a racy check of the value of the pmd to
ensure it maps a pte table. This should be fine, since races that
result in false-positive (i.e. attempt collapse even though we
shouldn't) will fail later in collapse_pte_mapped_thp() once we
actually lock mmap_lock and reinspect the pmd value. Races that result
in false-negatives (i.e. where we decide to not attempt collapse, but
should have) shouldn't be an issue, since in the worst case, we do
nothing - which is what we've done up to this point. We make a similar
check in retract_page_tables(). If we do think we've found a
pte-mapped hugepgae in khugepaged context, attempt to update page
tables mapping this hugepage.
Note that these collapses still count towards the
/sys/kernel/mm/transparent_hugepage/khugepaged/pages_collapsed counter,
and if the pte-mapped hugepage was also mapped into multiple process'
address spaces, could be incremented for each page table update. Since we
increment the counter when a pte-mapped hugepage is successfully added to
the list of to-collapse pte-mapped THPs, it's possible that we never
actually update the page table either. This is different from how
file/shmem pages_collapsed accounting works today where only a successful
page cache update is counted (it's also possible here that no page tables
are actually changed). Though it incurs some slop, this is preferred to
either not accounting for the event at all, or plumbing through data in
struct mm_slot on whether to account for the collapse or not.
Also note that work still needs to be done to support arbitrary compound
pages, and that this should all be converted to using folios.
[shy828301@gmail.com: Spelling mistake, update comment, and add Documentation]
Link: https://lore.kernel.org/linux-mm/CAHbLzkpHwZxFzjfX9nxVoRhzup8WMjMfyL6Xiq8mZ9M-N3ombw@mail.gmail.com/
Link: https://lkml.kernel.org/r/20220907144521.3115321-3-zokeefe@google.com
Link: https://lkml.kernel.org/r/20220922224046.1143204-3-zokeefe@google.com
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: add file/shmem support to MADV_COLLAPSE", v4.
This series builds on top of the previous "mm: userspace hugepage
collapse" series which introduced the MADV_COLLAPSE madvise mode and added
support for private, anonymous mappings[2], by adding support for file and
shmem backed memory to CONFIG_READ_ONLY_THP_FOR_FS=y kernels.
File and shmem support have been added with effort to align with existing
MADV_COLLAPSE semantics and policy decisions[3]. Collapse of shmem-backed
memory ignores kernel-guiding directives and heuristics including all
sysfs settings (transparent_hugepage/shmem_enabled), and tmpfs huge= mount
options (shmem always supports large folios). Like anonymous mappings, on
successful return of MADV_COLLAPSE on file/shmem memory, the contents of
memory mapped by the addresses provided will be synchronously pmd-mapped
THPs.
This functionality unlocks two important uses:
(1) Immediately back executable text by THPs. Current support provided
by CONFIG_READ_ONLY_THP_FOR_FS may take a long time on a large
system which might impair services from serving at their full rated
load after (re)starting. Tricks like mremap(2)'ing text onto
anonymous memory to immediately realize iTLB performance prevents
page sharing and demand paging, both of which increase steady state
memory footprint. Now, we can have the best of both worlds: Peak
upfront performance and lower RAM footprints.
(2) userfaultfd-based live migration of virtual machines satisfy UFFD
faults by fetching native-sized pages over the network (to avoid
latency of transferring an entire hugepage). However, after guest
memory has been fully copied to the new host, MADV_COLLAPSE can
be used to immediately increase guest performance.
khugepaged has received a small improvement by association and can now
detect and collapse pte-mapped THPs. However, there is still work to be
done along the file collapse path. Compound pages of arbitrary order
still needs to be supported and THP collapse needs to be converted to
using folios in general. Eventually, we'd like to move away from the
read-only and executable-mapped constraints currently imposed on eligible
files and support any inode claiming huge folio support. That said, I
think the series as-is covers enough to claim that MADV_COLLAPSE supports
file/shmem memory.
Patches 1-3 Implement the guts of the series.
Patch 4 Is a tracepoint for debugging.
Patches 5-9 Refactor existing khugepaged selftests to work with new
memory types + new collapse tests.
Patch 10 Adds a userfaultfd selftest mode to mimic a functional test
of UFFDIO_REGISTER_MODE_MINOR+MADV_COLLAPSE live migration.
(v4 note: "userfaultfd shmem" selftest is failing as of
Sep 22 mm-unstable)
[1] https://lore.kernel.org/linux-mm/YyiK8YvVcrtZo0z3@google.com/
[2] https://lore.kernel.org/linux-mm/20220706235936.2197195-1-zokeefe@google.com/
[3] https://lore.kernel.org/linux-mm/YtBmhaiPHUTkJml8@google.com/
[4] https://lore.kernel.org/linux-mm/20220922222731.1124481-1-zokeefe@google.com/
[5] https://lore.kernel.org/linux-mm/20220922184651.1016461-1-zokeefe@google.com/
This patch (of 10):
Extend 'mm/thp: add flag to enforce sysfs THP in hugepage_vma_check()' to
shmem, allowing callers to ignore
/sys/kernel/transparent_hugepage/shmem_enabled and tmpfs huge= mount.
This is intended to be used by MADV_COLLAPSE, and the rationale is
analogous to the anon/file case: MADV_COLLAPSE is not coupled to
directives that advise the kernel's decisions on when THPs should be
considered eligible. shmem/tmpfs always claims large folio support,
regardless of sysfs or mount options.
[shy828301@gmail.com: test shmem_huge_force explicitly]
Link: https://lore.kernel.org/linux-mm/CAHbLzko3A5-TpS0BgBeKkx5cuOkWgLvWXQH=TdgW-baO4rPtdg@mail.gmail.com/
Link: https://lkml.kernel.org/r/20220922224046.1143204-1-zokeefe@google.com
Link: https://lkml.kernel.org/r/20220907144521.3115321-2-zokeefe@google.com
Link: https://lkml.kernel.org/r/20220922224046.1143204-2-zokeefe@google.com
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
MADV_COLLAPSE is a best-effort request that attempts to set an actionable
errno value if the request cannot be fulfilled at the time. EAGAIN should
be used to communicate that a resource was temporarily unavailable, but
that the user may try again immediately.
SCAN_DEL_PAGE_LRU is an internal result code used when a page cannot be
isolated from it's LRU list. Since this, like SCAN_PAGE_LRU, is likely a
transitory state, make MADV_COLLAPSE return EAGAIN so that users know they
may reattempt the operation.
Another important scenario to consider is race with khugepaged.
khugepaged might isolate a page while MADV_COLLAPSE is interested in it.
Even though racing with khugepaged might mean that the memory has already
been collapsed, signalling an errno that is non-intrinsic to that memory
or arguments provided to madvise(2) lets the user know that future
attempts might (and in this case likely would) succeed, and avoids
false-negative assumptions by the user.
Link: https://lkml.kernel.org/r/20220922184651.1016461-1-zokeefe@google.com
Fixes: 7d8faaf155 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse")
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
By the time we lock a page in collapse_pte_mapped_thp(), the page mapped
by the address pushed onto the slot's .pte_mapped_thp[] array might have
changed arbitrarily since we last looked at it. We revalidate that the
page is still the head of a compound page, but we don't revalidate if the
compound page is of order HPAGE_PMD_ORDER before applying rmap and page
table updates.
Since the kernel now supports large folios of arbitrary order, and since
replacing page's pte mappings by a pmd mapping only makes sense for
compound pages of order HPAGE_PMD_ORDER, revalidate that the compound
order is indeed of order HPAGE_PMD_ORDER before proceeding.
Link: https://lore.kernel.org/linux-mm/CAHbLzkon+2ky8v9ywGcsTUgXM_B35jt5NThYqQKXW2YV_GUacw@mail.gmail.com/
Link: https://lkml.kernel.org/r/20220922222731.1124481-1-zokeefe@google.com
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Suggested-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The vma_lock and hugetlb_fault_mutex are dropped before handling userfault
and reacquire them again after handle_userfault(), but reacquire the
vma_lock could lead to UAF[1,2] due to the following race,
hugetlb_fault
hugetlb_no_page
/*unlock vma_lock */
hugetlb_handle_userfault
handle_userfault
/* unlock mm->mmap_lock*/
vm_mmap_pgoff
do_mmap
mmap_region
munmap_vma_range
/* clean old vma */
/* lock vma_lock again <--- UAF */
/* unlock vma_lock */
Since the vma_lock will unlock immediately after
hugetlb_handle_userfault(), let's drop the unneeded lock and unlock in
hugetlb_handle_userfault() to fix the issue.
[1] https://lore.kernel.org/linux-mm/000000000000d5e00a05e834962e@google.com/
[2] https://lore.kernel.org/linux-mm/20220921014457.1668-1-liuzixian4@huawei.com/
Link: https://lkml.kernel.org/r/20220923042113.137273-1-liushixin2@huawei.com
Fixes: 1a1aad8a9b ("userfaultfd: hugetlbfs: add userfaultfd hugetlb hook")
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reported-by: syzbot+193f9cee8638750b23cf@syzkaller.appspotmail.com
Reported-by: Liu Zixian <liuzixian4@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: <stable@vger.kernel.org> [4.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The bodies of damon_{reclaim,lru_sort}_apply_parameters() contain
duplicates. This commit adds a common function
damon_set_region_biggest_system_ram_default() to remove the duplicates.
Link: https://lkml.kernel.org/r/6329f00d.a70a0220.9bb29.3678SMTPIN_ADDED_BROKEN@mx.google.com
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We had better return the 'err' value when calling kstrtoul() failed, so
the user will know why it really fails, there do little change, let it
return the 'err' value when failed.
Link: https://lkml.kernel.org/r/6329ebe0.050a0220.ec4bd.297cSMTPIN_ADDED_BROKEN@mx.google.com
Suggested-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since commit 44042b4498 ("mm/page_alloc: allow high-order pages to be
stored on the per-cpu lists"), the per-cpu page allocators (PCP) is not
only for order-0 pages. Update the comments.
Link: https://lkml.kernel.org/r/20220918025640.208586-1-ran.xiaokai@zte.com.cn
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In the beginning there is only one damos_action 'DAMOS_PAGEOUT' that need
to get the coldness score of a region for a scheme, which using
damon_pageout_score() to do that. But now there are also other
damos_action actions need the coldness score, so rename it to
damon_cold_score() to make more sense.
Link: https://lkml.kernel.org/r/1663423014-28907-1-git-send-email-kaixuxia@tencent.com
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When creating hugetlb pages, the hugetlb code must first allocate
contiguous pages from a low level allocator such as buddy, cma or
memblock. The pages returned from these low level allocators are ref
counted. This creates potential issues with other code taking speculative
references on these pages before they can be transformed to a hugetlb
page. This issue has been addressed with methods and code such as that
provided in [1].
Recent discussions about vmemmap freeing [2] have indicated that it would
be beneficial to freeze all sub pages, including the head page of pages
returned from low level allocators before converting to a hugetlb page.
This helps avoid races if we want to replace the page containing vmemmap
for the head page.
There have been proposals to change at least the buddy allocator to return
frozen pages as described at [3]. If such a change is made, it can be
employed by the hugetlb code. However, as mentioned above hugetlb uses
several low level allocators so each would need to be modified to return
frozen pages. For now, we can manually freeze the returned pages. This
is done in two places:
1) alloc_buddy_huge_page, only the returned head page is ref counted.
We freeze the head page, retrying once in the VERY rare case where
there may be an inflated ref count.
2) prep_compound_gigantic_page, for gigantic pages the current code
freezes all pages except the head page. New code will simply freeze
the head page as well.
In a few other places, code checks for inflated ref counts on newly
allocated hugetlb pages. With the modifications to freeze after
allocating, this code can be removed.
After hugetlb pages are freshly allocated, they are often added to the
hugetlb free lists. Since these pages were previously ref counted, this
was done via put_page() which would end up calling the hugetlb destructor:
free_huge_page. With changes to freeze pages, we simply call
free_huge_page directly to add the pages to the free list.
In a few other places, freshly allocated hugetlb pages were immediately
put into use, and the expectation was they were already ref counted. In
these cases, we must manually ref count the page.
[1] https://lore.kernel.org/linux-mm/20210622021423.154662-3-mike.kravetz@oracle.com/
[2] https://lore.kernel.org/linux-mm/20220802180309.19340-1-joao.m.martins@oracle.com/
[3] https://lore.kernel.org/linux-mm/20220809171854.3725722-1-willy@infradead.org/
[mike.kravetz@oracle.com: fix NULL pointer dereference]
Link: https://lkml.kernel.org/r/20220921202702.106069-1-mike.kravetz@oracle.com
Link: https://lkml.kernel.org/r/20220916214638.155744-1-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There are no architectures that can have holes in the memory map within a
pageblock since commit 859a85ddf9 ("mm: remove pfn_valid_within() and
CONFIG_HOLES_IN_ZONE"). Update the corresponding comment.
Link: https://lkml.kernel.org/r/20220916072257.9639-17-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There's no need to check whether order > PAGE_ALLOC_COSTLY_ORDER again.
Minor readability improvement.
Link: https://lkml.kernel.org/r/20220916072257.9639-15-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The local variable buddy_pfn could be passed to buddy_merge_likely()
without initialization if the passed in order is MAX_ORDER - 1. This
looks buggy but buddy_pfn won't be used in this case as there's a order >=
MAX_ORDER - 2 check. Init buddy_pfn to 0 anyway to avoid possible future
misuse.
Link: https://lkml.kernel.org/r/20220916072257.9639-14-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use helper macro SZ_1K and SZ_1M to do the size conversion. Minor
readability improvement.
Link: https://lkml.kernel.org/r/20220916072257.9639-13-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It's only used in mm/page_alloc.c now. Make it static.
Link: https://lkml.kernel.org/r/20220916072257.9639-12-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use local variable zone_idx directly since it holds the exact value of
zone_idx(). No functional change intended.
Link: https://lkml.kernel.org/r/20220916072257.9639-10-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In MIGRATE_ISOLATE case, zone freepage state shouldn't be modified as
caller will take care of it. Add missing is_migrate_isolate() here to
avoid possible unbalanced freepage state. This would happen if someone
isolates the block, and then we face an MCE failure/soft-offline on a page
within that block. __mod_zone_freepage_state() will be triggered via
below call trace which already had been triggered back when block was
isolated:
take_page_off_buddy
break_down_buddy_pages
set_page_guard
Link: https://lkml.kernel.org/r/20220916072257.9639-9-linmiaohe@huawei.com
Fixes: 06be6ff3d2 ("mm,hwpoison: rework soft offline for free pages")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The size of struct per_cpu_zonestat can be 0 on !SMP && !NUMA. In that
case, zone->per_cpu_zonestats will always equal to boot_zonestats. But in
zone_pcp_reset(), zone->per_cpu_zonestats is freed via free_percpu()
directly without checking against boot_zonestats first. boot_zonestats
will be released by free_percpu() unexpectedly.
Link: https://lkml.kernel.org/r/20220916072257.9639-7-linmiaohe@huawei.com
Fixes: 28f836b677 ("mm/page_alloc: split per cpu page lists and zone stats")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It's only called by mm_init(). Add __init annotations to it.
Link: https://lkml.kernel.org/r/20220916072257.9639-6-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since commit 43c95bcc51 ("mm/page_alloc: reduce duration that IRQs are
disabled for VM counters"), zone_statistics() is not called with
interrupts disabled. Update the corresponding comment.
Link: https://lkml.kernel.org/r/20220916072257.9639-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since commit 8b10b465d0 ("mm/page_alloc: free pages in a single pass
during bulk free"), they're not used anymore. Remove them.
Link: https://lkml.kernel.org/r/20220916072257.9639-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since commit b92ca18e8c ("mm/page_alloc: disassociate the pcp->high from
pcp->batch"), zone_pcp_update() is only used in mm/page_alloc.c. Move
zone_pcp_update() up to avoid forward declaration and then make it static.
No functional change intended.
Link: https://lkml.kernel.org/r/20220916072257.9639-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "A few cleanup patches for mm", v2.
This series contains a few cleanup patches to remove the obsolete comments
and functions, use helper macro to improve readability and so on. More
details can be found in the respective changelogs.
This patch (of 16):
If ALLOC_KSWAPD is set, wake_all_kswapds() will be called to ensure kswapd
doesn't accidentally go to sleep. But when reserve_flags is set,
alloc_flags will be overwritten and ALLOC_KSWAPD is thus lost. Preserve
the ALLOC_KSWAPD flag in alloc_flags to ensure kswapd won't go to sleep
accidentally.
Link: https://lkml.kernel.org/r/20220916072257.9639-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20220916072257.9639-2-linmiaohe@huawei.com
Fixes: 0a79cdad5e ("mm: use alloc_flags to record if kswapd can wake")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is no point in returning an int from damon_set_schemes(). It always
returns 0 which is meaningless for the caller, so change it to return void
directly.
Link: https://lkml.kernel.org/r/1663341635-12675-1-git-send-email-kaixuxia@tencent.com
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_lru_sort_wmarks is only used in lru_sort.c now, change it to static.
Link: https://lkml.kernel.org/r/20220915021024.4177940-2-yangyingliang@huawei.com
Fixes: 189aa3d58206 ("mm/damon/lru_sort: use watermarks parameters generator macro")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam Howlett