Now that call_rcu()'s callback is not invoked until after all
preempt-disable regions of code have completed (in addition to explicitly
marked RCU read-side critical sections), call_rcu() can be used in place
of call_rcu_sched(). This commit therefore makes that change.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Now that synchronize_rcu() waits for preempt-disable regions of code
as well as RCU read-side critical sections, synchronize_sched() can be
replaced by synchronize_rcu(). This commit therefore makes this change.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>
Konstantin has noticed that kvmalloc might trigger the following
warning:
WARNING: CPU: 0 PID: 6676 at mm/vmstat.c:986 __fragmentation_index+0x54/0x60
[...]
Call Trace:
fragmentation_index+0x76/0x90
compaction_suitable+0x4f/0xf0
shrink_node+0x295/0x310
node_reclaim+0x205/0x250
get_page_from_freelist+0x649/0xad0
__alloc_pages_nodemask+0x12a/0x2a0
kmalloc_large_node+0x47/0x90
__kmalloc_node+0x22b/0x2e0
kvmalloc_node+0x3e/0x70
xt_alloc_table_info+0x3a/0x80 [x_tables]
do_ip6t_set_ctl+0xcd/0x1c0 [ip6_tables]
nf_setsockopt+0x44/0x60
SyS_setsockopt+0x6f/0xc0
do_syscall_64+0x67/0x120
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
the problem is that we only check for an out of bound order in the slow
path and the node reclaim might happen from the fast path already. This
is fixable by making sure that kvmalloc doesn't ever use kmalloc for
requests that are larger than KMALLOC_MAX_SIZE but this also shows that
the code is rather fragile. A recent UBSAN report just underlines that
by the following report
UBSAN: Undefined behaviour in mm/page_alloc.c:3117:19
shift exponent 51 is too large for 32-bit type 'int'
CPU: 0 PID: 6520 Comm: syz-executor1 Not tainted 4.19.0-rc2 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xd2/0x148 lib/dump_stack.c:113
ubsan_epilogue+0x12/0x94 lib/ubsan.c:159
__ubsan_handle_shift_out_of_bounds+0x2b6/0x30b lib/ubsan.c:425
__zone_watermark_ok+0x2c7/0x400 mm/page_alloc.c:3117
zone_watermark_fast mm/page_alloc.c:3216 [inline]
get_page_from_freelist+0xc49/0x44c0 mm/page_alloc.c:3300
__alloc_pages_nodemask+0x21e/0x640 mm/page_alloc.c:4370
alloc_pages_current+0xcc/0x210 mm/mempolicy.c:2093
alloc_pages include/linux/gfp.h:509 [inline]
__get_free_pages+0x12/0x60 mm/page_alloc.c:4414
dma_mem_alloc+0x36/0x50 arch/x86/include/asm/floppy.h:156
raw_cmd_copyin drivers/block/floppy.c:3159 [inline]
raw_cmd_ioctl drivers/block/floppy.c:3206 [inline]
fd_locked_ioctl+0xa00/0x2c10 drivers/block/floppy.c:3544
fd_ioctl+0x40/0x60 drivers/block/floppy.c:3571
__blkdev_driver_ioctl block/ioctl.c:303 [inline]
blkdev_ioctl+0xb3c/0x1a30 block/ioctl.c:601
block_ioctl+0x105/0x150 fs/block_dev.c:1883
vfs_ioctl fs/ioctl.c:46 [inline]
do_vfs_ioctl+0x1c0/0x1150 fs/ioctl.c:687
ksys_ioctl+0x9e/0xb0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x7e/0xc0 fs/ioctl.c:707
do_syscall_64+0xc4/0x510 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Note that this is not a kvmalloc path. It is just that the fast path
really depends on having sanitzed order as well. Therefore move the
order check to the fast path.
Link: http://lkml.kernel.org/r/20181113094305.GM15120@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reported-by: Kyungtae Kim <kt0755@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Byoungyoung Lee <lifeasageek@gmail.com>
Cc: "Dae R. Jeong" <threeearcat@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Other filesystems such as ext4, f2fs and ubifs all return ENXIO when
lseek (SEEK_DATA or SEEK_HOLE) requests a negative offset.
man 2 lseek says
: EINVAL whence is not valid. Or: the resulting file offset would be
: negative, or beyond the end of a seekable device.
:
: ENXIO whence is SEEK_DATA or SEEK_HOLE, and the file offset is beyond
: the end of the file.
Make tmpfs return ENXIO under these circumstances as well. After this,
tmpfs also passes xfstests's generic/448.
[akpm@linux-foundation.org: rewrite changelog]
Link: http://lkml.kernel.org/r/1540434176-14349-1-git-send-email-yuyufen@huawei.com
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Scan through the whole array to see if an update is needed. While we're
at it, use sizeof() to be safe against any possible type changes in the
future.
The bug here is that we wouldn't sync per-cpu counters into global ones
if there was an update of numa_stats for higher cpus. Highly
theoretical one though because it is much more probable that zone_stats
are updated so we would refresh anyway. So I wouldn't bother to mark
this for stable, yet something nice to fix.
[mhocko@suse.com: changelog enhancement]
Link: http://lkml.kernel.org/r/1541601517-17282-1-git-send-email-janne.huttunen@nokia.com
Fixes: 1d90ca897c ("mm: update NUMA counter threshold size")
Signed-off-by: Janne Huttunen <janne.huttunen@nokia.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit df06b37ffe ("mm/gup: cache dev_pagemap while pinning pages")
modified the signature of follow_page_mask() but left the parameter
description behind.
Update the description to make the code and comments agree again.
While at it, update formatting of the return value description to match
Documentation/doc-guide/kernel-doc.rst guidelines.
Link: http://lkml.kernel.org/r/1541603316-27832-1-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Page state checks are racy. Under a heavy memory workload (e.g. stress
-m 200 -t 2h) it is quite easy to hit a race window when the page is
allocated but its state is not fully populated yet. A debugging patch to
dump the struct page state shows
has_unmovable_pages: pfn:0x10dfec00, found:0x1, count:0x0
page:ffffea0437fb0000 count:1 mapcount:1 mapping:ffff880e05239841 index:0x7f26e5000 compound_mapcount: 1
flags: 0x5fffffc0090034(uptodate|lru|active|head|swapbacked)
Note that the state has been checked for both PageLRU and PageSwapBacked
already. Closing this race completely would require some sort of retry
logic. This can be tricky and error prone (think of potential endless
or long taking loops).
Workaround this problem for movable zones at least. Such a zone should
only contain movable pages. Commit 15c30bc090 ("mm, memory_hotplug:
make has_unmovable_pages more robust") has told us that this is not
strictly true though. Bootmem pages should be marked reserved though so
we can move the original check after the PageReserved check. Pages from
other zones are still prone to races but we even do not pretend that
memory hotremove works for those so pre-mature failure doesn't hurt that
much.
Link: http://lkml.kernel.org/r/20181106095524.14629-1-mhocko@kernel.org
Fixes: 15c30bc090 ("mm, memory_hotplug: make has_unmovable_pages more robust")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Baoquan He <bhe@redhat.com>
Tested-by: Baoquan He <bhe@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit a2468cc9bf ("swap: choose swap device according to numa node")
changed 'avail_lists' field of 'struct swap_info_struct' to an array.
In popular linux distros it increased size of swap_info_struct up to 40
Kbytes and now swap_info_struct allocation requires order-4 page.
Switch to kvzmalloc allows to avoid unexpected allocation failures.
Link: http://lkml.kernel.org/r/fc23172d-3c75-21e2-d551-8b1808cbe593@virtuozzo.com
Fixes: a2468cc9bf ("swap: choose swap device according to numa node")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Acked-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This bug has been experienced several times by the Oracle DB team. The
BUG is in remove_inode_hugepages() as follows:
/*
* If page is mapped, it was faulted in after being
* unmapped in caller. Unmap (again) now after taking
* the fault mutex. The mutex will prevent faults
* until we finish removing the page.
*
* This race can only happen in the hole punch case.
* Getting here in a truncate operation is a bug.
*/
if (unlikely(page_mapped(page))) {
BUG_ON(truncate_op);
In this case, the elevated map count is not the result of a race.
Rather it was incorrectly incremented as the result of a bug in the huge
pmd sharing code. Consider the following:
- Process A maps a hugetlbfs file of sufficient size and alignment
(PUD_SIZE) that a pmd page could be shared.
- Process B maps the same hugetlbfs file with the same size and
alignment such that a pmd page is shared.
- Process B then calls mprotect() to change protections for the mapping
with the shared pmd. As a result, the pmd is 'unshared'.
- Process B then calls mprotect() again to chage protections for the
mapping back to their original value. pmd remains unshared.
- Process B then forks and process C is created. During the fork
process, we do dup_mm -> dup_mmap -> copy_page_range to copy page
tables. Copying page tables for hugetlb mappings is done in the
routine copy_hugetlb_page_range.
In copy_hugetlb_page_range(), the destination pte is obtained by:
dst_pte = huge_pte_alloc(dst, addr, sz);
If pmd sharing is possible, the returned pointer will be to a pte in an
existing page table. In the situation above, process C could share with
either process A or process B. Since process A is first in the list,
the returned pte is a pointer to a pte in process A's page table.
However, the check for pmd sharing in copy_hugetlb_page_range is:
/* If the pagetables are shared don't copy or take references */
if (dst_pte == src_pte)
continue;
Since process C is sharing with process A instead of process B, the
above test fails. The code in copy_hugetlb_page_range which follows
assumes dst_pte points to a huge_pte_none pte. It copies the pte entry
from src_pte to dst_pte and increments this map count of the associated
page. This is how we end up with an elevated map count.
To solve, check the dst_pte entry for huge_pte_none. If !none, this
implies PMD sharing so do not copy.
Link: http://lkml.kernel.org/r/20181105212315.14125-1-mike.kravetz@oracle.com
Fixes: c5c99429fa ("fix hugepages leak due to pagetable page sharing")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reclaim and free can race on an object which is basically fine but in
order for reclaim to be able to map "freed" object we need to encode
object length in the handle. handle_to_chunks() is then introduced to
extract object length from a handle and use it during mapping.
Moreover, to avoid racing on a z3fold "headless" page release, we should
not try to free that page in z3fold_free() if the reclaim bit is set.
Also, in the unlikely case of trying to reclaim a page being freed, we
should not proceed with that page.
While at it, fix the page accounting in reclaim function.
This patch supersedes "[PATCH] z3fold: fix reclaim lock-ups".
Link: http://lkml.kernel.org/r/20181105162225.74e8837d03583a9b707cf559@gmail.com
Signed-off-by: Vitaly Wool <vitaly.vul@sony.com>
Signed-off-by: Jongseok Kim <ks77sj@gmail.com>
Reported-by-by: Jongseok Kim <ks77sj@gmail.com>
Reviewed-by: Snild Dolkow <snild@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lockdep_assert_held() is better suited to checking locking requirements,
since it only checks if the current thread holds the lock regardless of
whether someone else does. This is also a step towards possibly removing
spin_is_locked().
Signed-off-by: Lance Roy <ldr709@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: <linux-mm@kvack.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
The i915 driver uses shmemfs to allocate backing storage for gem
objects. These shmemfs pages can be pinned (increased ref count) by
shmem_read_mapping_page_gfp(). When a lot of pages are pinned, vmscan
wastes a lot of time scanning these pinned pages. In some extreme case,
all pages in the inactive anon lru are pinned, and only the inactive
anon lru is scanned due to inactive_ratio, the system cannot swap and
invokes the oom-killer. Mark these pinned pages as unevictable to speed
up vmscan.
Export pagevec API check_move_unevictable_pages().
This patch was inspired by Chris Wilson's change [1].
[1]: https://patchwork.kernel.org/patch/9768741/
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Kuo-Hsin Yang <vovoy@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com> # mm part
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20181106132324.17390-1-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
We have received a bug report that unbinding a large pmem (>1TB) can
result in a soft lockup:
NMI watchdog: BUG: soft lockup - CPU#9 stuck for 23s! [ndctl:4365]
[...]
Supported: Yes
CPU: 9 PID: 4365 Comm: ndctl Not tainted 4.12.14-94.40-default #1 SLE12-SP4
Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.01.00.0833.051120182255 05/11/2018
task: ffff9cce7d4410c0 task.stack: ffffbe9eb1bc4000
RIP: 0010:__put_page+0x62/0x80
Call Trace:
devm_memremap_pages_release+0x152/0x260
release_nodes+0x18d/0x1d0
device_release_driver_internal+0x160/0x210
unbind_store+0xb3/0xe0
kernfs_fop_write+0x102/0x180
__vfs_write+0x26/0x150
vfs_write+0xad/0x1a0
SyS_write+0x42/0x90
do_syscall_64+0x74/0x150
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x7fd13166b3d0
It has been reported on an older (4.12) kernel but the current upstream
code doesn't cond_resched in the hot remove code at all and the given
range to remove might be really large. Fix the issue by calling
cond_resched once per memory section.
Link: http://lkml.kernel.org/r/20181031125840.23982-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Dan Williams <dan.j.williams@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
THP allocation mode is quite complex and it depends on the defrag mode.
This complexity is hidden in alloc_hugepage_direct_gfpmask from a large
part currently. The NUMA special casing (namely __GFP_THISNODE) is
however independent and placed in alloc_pages_vma currently. This both
adds an unnecessary branch to all vma based page allocation requests and
it makes the code more complex unnecessarily as well. Not to mention
that e.g. shmem THP used to do the node reclaiming unconditionally
regardless of the defrag mode until recently. This was not only
unexpected behavior but it was also hardly a good default behavior and I
strongly suspect it was just a side effect of the code sharing more than
a deliberate decision which suggests that such a layering is wrong.
Get rid of the thp special casing from alloc_pages_vma and move the
logic to alloc_hugepage_direct_gfpmask. __GFP_THISNODE is applied to the
resulting gfp mask only when the direct reclaim is not requested and
when there is no explicit numa binding to preserve the current logic.
Please note that there's also a slight difference wrt MPOL_BIND now. The
previous code would avoid using __GFP_THISNODE if the local node was
outside of policy_nodemask(). After this patch __GFP_THISNODE is avoided
for all MPOL_BIND policies. So there's a difference that if local node
is actually allowed by the bind policy's nodemask, previously
__GFP_THISNODE would be added, but now it won't be. From the behavior
POV this is still correct because the policy nodemask is used.
Link: http://lkml.kernel.org/r/20180925120326.24392-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
THP allocation might be really disruptive when allocated on NUMA system
with the local node full or hard to reclaim. Stefan has posted an
allocation stall report on 4.12 based SLES kernel which suggests the
same issue:
kvm: page allocation stalls for 194572ms, order:9, mode:0x4740ca(__GFP_HIGHMEM|__GFP_IO|__GFP_FS|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_THISNODE|__GFP_MOVABLE|__GFP_DIRECT_RECLAIM), nodemask=(null)
kvm cpuset=/ mems_allowed=0-1
CPU: 10 PID: 84752 Comm: kvm Tainted: G W 4.12.0+98-ph <a href="/view.php?id=1" title="[geschlossen] Integration Ramdisk" class="resolved">0000001</a> SLE15 (unreleased)
Hardware name: Supermicro SYS-1029P-WTRT/X11DDW-NT, BIOS 2.0 12/05/2017
Call Trace:
dump_stack+0x5c/0x84
warn_alloc+0xe0/0x180
__alloc_pages_slowpath+0x820/0xc90
__alloc_pages_nodemask+0x1cc/0x210
alloc_pages_vma+0x1e5/0x280
do_huge_pmd_wp_page+0x83f/0xf00
__handle_mm_fault+0x93d/0x1060
handle_mm_fault+0xc6/0x1b0
__do_page_fault+0x230/0x430
do_page_fault+0x2a/0x70
page_fault+0x7b/0x80
[...]
Mem-Info:
active_anon:126315487 inactive_anon:1612476 isolated_anon:5
active_file:60183 inactive_file:245285 isolated_file:0
unevictable:15657 dirty:286 writeback:1 unstable:0
slab_reclaimable:75543 slab_unreclaimable:2509111
mapped:81814 shmem:31764 pagetables:370616 bounce:0
free:32294031 free_pcp:6233 free_cma:0
Node 0 active_anon:254680388kB inactive_anon:1112760kB active_file:240648kB inactive_file:981168kB unevictable:13368kB isolated(anon):0kB isolated(file):0kB mapped:280240kB dirty:1144kB writeback:0kB shmem:95832kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 81225728kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no
Node 1 active_anon:250583072kB inactive_anon:5337144kB active_file:84kB inactive_file:0kB unevictable:49260kB isolated(anon):20kB isolated(file):0kB mapped:47016kB dirty:0kB writeback:4kB shmem:31224kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 31897600kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no
The defrag mode is "madvise" and from the above report it is clear that
the THP has been allocated for MADV_HUGEPAGA vma.
Andrea has identified that the main source of the problem is
__GFP_THISNODE usage:
: The problem is that direct compaction combined with the NUMA
: __GFP_THISNODE logic in mempolicy.c is telling reclaim to swap very
: hard the local node, instead of failing the allocation if there's no
: THP available in the local node.
:
: Such logic was ok until __GFP_THISNODE was added to the THP allocation
: path even with MPOL_DEFAULT.
:
: The idea behind the __GFP_THISNODE addition, is that it is better to
: provide local memory in PAGE_SIZE units than to use remote NUMA THP
: backed memory. That largely depends on the remote latency though, on
: threadrippers for example the overhead is relatively low in my
: experience.
:
: The combination of __GFP_THISNODE and __GFP_DIRECT_RECLAIM results in
: extremely slow qemu startup with vfio, if the VM is larger than the
: size of one host NUMA node. This is because it will try very hard to
: unsuccessfully swapout get_user_pages pinned pages as result of the
: __GFP_THISNODE being set, instead of falling back to PAGE_SIZE
: allocations and instead of trying to allocate THP on other nodes (it
: would be even worse without vfio type1 GUP pins of course, except it'd
: be swapping heavily instead).
Fix this by removing __GFP_THISNODE for THP requests which are
requesting the direct reclaim. This effectivelly reverts 5265047ac3
on the grounds that the zone/node reclaim was known to be disruptive due
to premature reclaim when there was memory free. While it made sense at
the time for HPC workloads without NUMA awareness on rare machines, it
was ultimately harmful in the majority of cases. The existing behaviour
is similar, if not as widespare as it applies to a corner case but
crucially, it cannot be tuned around like zone_reclaim_mode can. The
default behaviour should always be to cause the least harm for the
common case.
If there are specialised use cases out there that want zone_reclaim_mode
in specific cases, then it can be built on top. Longterm we should
consider a memory policy which allows for the node reclaim like behavior
for the specific memory ranges which would allow a
[1] http://lkml.kernel.org/r/20180820032204.9591-1-aarcange@redhat.com
Mel said:
: Both patches look correct to me but I'm responding to this one because
: it's the fix. The change makes sense and moves further away from the
: severe stalling behaviour we used to see with both THP and zone reclaim
: mode.
:
: I put together a basic experiment with usemem configured to reference a
: buffer multiple times that is 80% the size of main memory on a 2-socket
: box with symmetric node sizes and defrag set to "always". The defrag
: setting is not the default but it would be functionally similar to
: accessing a buffer with madvise(MADV_HUGEPAGE). Usemem is configured to
: reference the buffer multiple times and while it's not an interesting
: workload, it would be expected to complete reasonably quickly as it fits
: within memory. The results were;
:
: usemem
: vanilla noreclaim-v1
: Amean Elapsd-1 42.78 ( 0.00%) 26.87 ( 37.18%)
: Amean Elapsd-3 27.55 ( 0.00%) 7.44 ( 73.00%)
: Amean Elapsd-4 5.72 ( 0.00%) 5.69 ( 0.45%)
:
: This shows the elapsed time in seconds for 1 thread, 3 threads and 4
: threads referencing buffers 80% the size of memory. With the patches
: applied, it's 37.18% faster for the single thread and 73% faster with two
: threads. Note that 4 threads showing little difference does not indicate
: the problem is related to thread counts. It's simply the case that 4
: threads gets spread so their workload mostly fits in one node.
:
: The overall view from /proc/vmstats is more startling
:
: 4.19.0-rc1 4.19.0-rc1
: vanillanoreclaim-v1r1
: Minor Faults 35593425 708164
: Major Faults 484088 36
: Swap Ins 3772837 0
: Swap Outs 3932295 0
:
: Massive amounts of swap in/out without the patch
:
: Direct pages scanned 6013214 0
: Kswapd pages scanned 0 0
: Kswapd pages reclaimed 0 0
: Direct pages reclaimed 4033009 0
:
: Lots of reclaim activity without the patch
:
: Kswapd efficiency 100% 100%
: Kswapd velocity 0.000 0.000
: Direct efficiency 67% 100%
: Direct velocity 11191.956 0.000
:
: Mostly from direct reclaim context as you'd expect without the patch.
:
: Page writes by reclaim 3932314.000 0.000
: Page writes file 19 0
: Page writes anon 3932295 0
: Page reclaim immediate 42336 0
:
: Writes from reclaim context is never good but the patch eliminates it.
:
: We should never have default behaviour to thrash the system for such a
: basic workload. If zone reclaim mode behaviour is ever desired but on a
: single task instead of a global basis then the sensible option is to build
: a mempolicy that enforces that behaviour.
This was a severe regression compared to previous kernels that made
important workloads unusable and it starts when __GFP_THISNODE was
added to THP allocations under MADV_HUGEPAGE. It is not a significant
risk to go to the previous behavior before __GFP_THISNODE was added, it
worked like that for years.
This was simply an optimization to some lucky workloads that can fit in
a single node, but it ended up breaking the VM for others that can't
possibly fit in a single node, so going back is safe.
[mhocko@suse.com: rewrote the changelog based on the one from Andrea]
Link: http://lkml.kernel.org/r/20180925120326.24392-2-mhocko@kernel.org
Fixes: 5265047ac3 ("mm, thp: really limit transparent hugepage allocation to local node")
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Stefan Priebe <s.priebe@profihost.ag>
Debugged-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Mel Gorman <mgorman@techsingularity.net>
Tested-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: <stable@vger.kernel.org> [4.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Galbraith reported a regression caused by the commit 9b6f7e163c
("mm: rework memcg kernel stack accounting") on a system with
"cgroup_disable=memory" boot option: the system panics with the following
stack trace:
BUG: unable to handle kernel NULL pointer dereference at 00000000000000f8
PGD 0 P4D 0
Oops: 0002 [#1] PREEMPT SMP PTI
CPU: 0 PID: 1 Comm: systemd Not tainted 4.19.0-preempt+ #410
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20180531_142017-buildhw-08.phx2.fed4
RIP: 0010:page_counter_try_charge+0x22/0xc0
Code: 41 5d c3 c3 0f 1f 40 00 0f 1f 44 00 00 48 85 ff 0f 84 a7 00 00 00 41 56 48 89 f8 49 89 fe 49
Call Trace:
try_charge+0xcb/0x780
memcg_kmem_charge_memcg+0x28/0x80
memcg_kmem_charge+0x8b/0x1d0
copy_process.part.41+0x1ca/0x2070
_do_fork+0xd7/0x3d0
do_syscall_64+0x5a/0x180
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The problem occurs because get_mem_cgroup_from_current() returns the NULL
pointer if memory controller is disabled. Let's check if this is a case
at the beginning of memcg_kmem_charge() and just return 0 if
mem_cgroup_disabled() returns true. This is how we handle this case in
many other places in the memory controller code.
Link: http://lkml.kernel.org/r/20181029215123.17830-1-guro@fb.com
Fixes: 9b6f7e163c ("mm: rework memcg kernel stack accounting")
Signed-off-by: Roman Gushchin <guro@fb.com>
Reported-by: Mike Galbraith <efault@gmx.de>
Acked-by: Rik van Riel <riel@surriel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'for-linus-20181102' of git://git.kernel.dk/linux-block
Pull block layer fixes from Jens Axboe:
"The biggest part of this pull request is the revert of the blkcg
cleanup series. It had one fix earlier for a stacked device issue, but
another one was reported. Rather than play whack-a-mole with this,
revert the entire series and try again for the next kernel release.
Apart from that, only small fixes/changes.
Summary:
- Indentation fixup for mtip32xx (Colin Ian King)
- The blkcg cleanup series revert (Dennis Zhou)
- Two NVMe fixes. One fixing a regression in the nvme request
initialization in this merge window, causing nvme-fc to not work.
The other is a suspend/resume p2p resource issue (James, Keith)
- Fix sg discard merge, allowing us to merge in cases where we didn't
before (Jianchao Wang)
- Call rq_qos_exit() after the queue is frozen, preventing a hang
(Ming)
- Fix brd queue setup, fixing an oops if we fail setting up all
devices (Ming)"
* tag 'for-linus-20181102' of git://git.kernel.dk/linux-block:
nvme-pci: fix conflicting p2p resource adds
nvme-fc: fix request private initialization
blkcg: revert blkcg cleanups series
block: brd: associate with queue until adding disk
block: call rq_qos_exit() after queue is frozen
mtip32xx: clean an indentation issue, remove extraneous tabs
block: fix the DISCARD request merge
Rework the vfs_clone_file_range and vfs_dedupe_file_range infrastructure to use
a common .remap_file_range method and supply generic bounds and sanity checking
functions that are shared with the data write path. The current VFS
infrastructure has problems with rlimit, LFS file sizes, file time stamps,
maximum filesystem file sizes, stripping setuid bits, etc and so they are
addressed in these commits.
We also introduce the ability for the ->remap_file_range methods to return short
clones so that clones for vfs_copy_file_range() don't get rejected if the entire
range can't be cloned. It also allows filesystems to sliently skip deduplication
of partial EOF blocks if they are not capable of doing so without requiring
errors to be thrown to userspace.
All existing filesystems are converted to user the new .remap_file_range method,
and both XFS and ocfs2 are modified to make use of the new generic checking
infrastructure.
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Merge tag 'xfs-4.20-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull vfs dedup fixes from Dave Chinner:
"This reworks the vfs data cloning infrastructure.
We discovered many issues with these interfaces late in the 4.19 cycle
- the worst of them (data corruption, setuid stripping) were fixed for
XFS in 4.19-rc8, but a larger rework of the infrastructure fixing all
the problems was needed. That rework is the contents of this pull
request.
Rework the vfs_clone_file_range and vfs_dedupe_file_range
infrastructure to use a common .remap_file_range method and supply
generic bounds and sanity checking functions that are shared with the
data write path. The current VFS infrastructure has problems with
rlimit, LFS file sizes, file time stamps, maximum filesystem file
sizes, stripping setuid bits, etc and so they are addressed in these
commits.
We also introduce the ability for the ->remap_file_range methods to
return short clones so that clones for vfs_copy_file_range() don't get
rejected if the entire range can't be cloned. It also allows
filesystems to sliently skip deduplication of partial EOF blocks if
they are not capable of doing so without requiring errors to be thrown
to userspace.
Existing filesystems are converted to user the new remap_file_range
method, and both XFS and ocfs2 are modified to make use of the new
generic checking infrastructure"
* tag 'xfs-4.20-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (28 commits)
xfs: remove [cm]time update from reflink calls
xfs: remove xfs_reflink_remap_range
xfs: remove redundant remap partial EOF block checks
xfs: support returning partial reflink results
xfs: clean up xfs_reflink_remap_blocks call site
xfs: fix pagecache truncation prior to reflink
ocfs2: remove ocfs2_reflink_remap_range
ocfs2: support partial clone range and dedupe range
ocfs2: fix pagecache truncation prior to reflink
ocfs2: truncate page cache for clone destination file before remapping
vfs: clean up generic_remap_file_range_prep return value
vfs: hide file range comparison function
vfs: enable remap callers that can handle short operations
vfs: plumb remap flags through the vfs dedupe functions
vfs: plumb remap flags through the vfs clone functions
vfs: make remap_file_range functions take and return bytes completed
vfs: remap helper should update destination inode metadata
vfs: pass remap flags to generic_remap_checks
vfs: pass remap flags to generic_remap_file_range_prep
vfs: combine the clone and dedupe into a single remap_file_range
...
Pull AFS updates from Al Viro:
"AFS series, with some iov_iter bits included"
* 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
missing bits of "iov_iter: Separate type from direction and use accessor functions"
afs: Probe multiple fileservers simultaneously
afs: Fix callback handling
afs: Eliminate the address pointer from the address list cursor
afs: Allow dumping of server cursor on operation failure
afs: Implement YFS support in the fs client
afs: Expand data structure fields to support YFS
afs: Get the target vnode in afs_rmdir() and get a callback on it
afs: Calc callback expiry in op reply delivery
afs: Fix FS.FetchStatus delivery from updating wrong vnode
afs: Implement the YFS cache manager service
afs: Remove callback details from afs_callback_break struct
afs: Commit the status on a new file/dir/symlink
afs: Increase to 64-bit volume ID and 96-bit vnode ID for YFS
afs: Don't invoke the server to read data beyond EOF
afs: Add a couple of tracepoints to log I/O errors
afs: Handle EIO from delivery function
afs: Fix TTL on VL server and address lists
afs: Implement VL server rotation
afs: Improve FS server rotation error handling
...
virtio balloon page hinting support
vhost scsi control queue
misc fixes.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
Pull virtio/vhost updates from Michael Tsirkin:
"Fixes and tweaks:
- virtio balloon page hinting support
- vhost scsi control queue
- misc fixes"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
MAINTAINERS: remove reference to bogus vsock file
vhost/scsi: Use common handling code in request queue handler
vhost/scsi: Extract common handling code from control queue handler
vhost/scsi: Respond to control queue operations
vhost/scsi: truncate T10 PI iov_iter to prot_bytes
virtio-balloon: VIRTIO_BALLOON_F_PAGE_POISON
mm/page_poison: expose page_poisoning_enabled to kernel modules
virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT
kvm_config: add CONFIG_VIRTIO_MENU
Pull percpu fixes from Dennis Zhou:
"Two small things for v4.20.
The first fixes a clang uninitialized variable warning for arm64 in
the default path calls BUILD_BUG(). The second removes an unnecessary
unlikely() in a WARN_ON() use"
* 'for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu:
arm64: percpu: Initialize ret in the default case
mm: percpu: remove unnecessary unlikely()
In DAX mode a write pagefault can race with write(2) in the following
way:
CPU0 CPU1
write fault for mapped zero page (hole)
dax_iomap_rw()
iomap_apply()
xfs_file_iomap_begin()
- allocates blocks
dax_iomap_actor()
invalidate_inode_pages2_range()
- invalidates radix tree entries in given range
dax_iomap_pte_fault()
grab_mapping_entry()
- no entry found, creates empty
...
xfs_file_iomap_begin()
- finds already allocated block
...
vmf_insert_mixed_mkwrite()
- WARNs and does nothing because there
is still zero page mapped in PTE
unmap_mapping_pages()
This race results in WARN_ON from insert_pfn() and is occasionally
triggered by fstest generic/344. Note that the race is otherwise
harmless as before write(2) on CPU0 is finished, we will invalidate page
tables properly and thus user of mmap will see modified data from
write(2) from that point on. So just restrict the warning only to the
case when the PFN in PTE is not zero page.
Link: http://lkml.kernel.org/r/20180824154542.26872-1-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There seem to be some problems as result of 30467e0b3b ("mm, hotplug:
fix concurrent memory hot-add deadlock"), which tried to fix a possible
lock inversion reported and discussed in [1] due to the two locks
a) device_lock()
b) mem_hotplug_lock
While add_memory() first takes b), followed by a) during
bus_probe_device(), onlining of memory from user space first took a),
followed by b), exposing a possible deadlock.
In [1], and it was decided to not make use of device_hotplug_lock, but
rather to enforce a locking order.
The problems I spotted related to this:
1. Memory block device attributes: While .state first calls
mem_hotplug_begin() and the calls device_online() - which takes
device_lock() - .online does no longer call mem_hotplug_begin(), so
effectively calls online_pages() without mem_hotplug_lock.
2. device_online() should be called under device_hotplug_lock, however
onlining memory during add_memory() does not take care of that.
In addition, I think there is also something wrong about the locking in
3. arch/powerpc/platforms/powernv/memtrace.c calls offline_pages()
without locks. This was introduced after 30467e0b3b. And skimming over
the code, I assume it could need some more care in regards to locking
(e.g. device_online() called without device_hotplug_lock. This will
be addressed in the following patches.
Now that we hold the device_hotplug_lock when
- adding memory (e.g. via add_memory()/add_memory_resource())
- removing memory (e.g. via remove_memory())
- device_online()/device_offline()
We can move mem_hotplug_lock usage back into
online_pages()/offline_pages().
Why is mem_hotplug_lock still needed? Essentially to make
get_online_mems()/put_online_mems() be very fast (relying on
device_hotplug_lock would be very slow), and to serialize against
addition of memory that does not create memory block devices (hmm).
[1] http://driverdev.linuxdriverproject.org/pipermail/ driverdev-devel/
2015-February/065324.html
This patch is partly based on a patch by Vitaly Kuznetsov.
Link: http://lkml.kernel.org/r/20180925091457.28651-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Rashmica Gupta <rashmica.g@gmail.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
add_memory() currently does not take the device_hotplug_lock, however
is aleady called under the lock from
arch/powerpc/platforms/pseries/hotplug-memory.c
drivers/acpi/acpi_memhotplug.c
to synchronize against CPU hot-remove and similar.
In general, we should hold the device_hotplug_lock when adding memory to
synchronize against online/offline request (e.g. from user space) - which
already resulted in lock inversions due to device_lock() and
mem_hotplug_lock - see 30467e0b3b ("mm, hotplug: fix concurrent memory
hot-add deadlock"). add_memory()/add_memory_resource() will create memory
block devices, so this really feels like the right thing to do.
Holding the device_hotplug_lock makes sure that a memory block device
can really only be accessed (e.g. via .online/.state) from user space,
once the memory has been fully added to the system.
The lock is not held yet in
drivers/xen/balloon.c
arch/powerpc/platforms/powernv/memtrace.c
drivers/s390/char/sclp_cmd.c
drivers/hv/hv_balloon.c
So, let's either use the locked variants or take the lock.
Don't export add_memory_resource(), as it once was exported to be used by
XEN, which is never built as a module. If somebody requires it, we also
have to export a locked variant (as device_hotplug_lock is never
exported).
Link: http://lkml.kernel.org/r/20180925091457.28651-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: online/offline_pages called w.o. mem_hotplug_lock", v3.
Reading through the code and studying how mem_hotplug_lock is to be used,
I noticed that there are two places where we can end up calling
device_online()/device_offline() - online_pages()/offline_pages() without
the mem_hotplug_lock. And there are other places where we call
device_online()/device_offline() without the device_hotplug_lock.
While e.g.
echo "online" > /sys/devices/system/memory/memory9/state
is fine, e.g.
echo 1 > /sys/devices/system/memory/memory9/online
Will not take the mem_hotplug_lock. However the device_lock() and
device_hotplug_lock.
E.g. via memory_probe_store(), we can end up calling
add_memory()->online_pages() without the device_hotplug_lock. So we can
have concurrent callers in online_pages(). We e.g. touch in
online_pages() basically unprotected zone->present_pages then.
Looks like there is a longer history to that (see Patch #2 for details),
and fixing it to work the way it was intended is not really possible. We
would e.g. have to take the mem_hotplug_lock in device/base/core.c, which
sounds wrong.
Summary: We had a lock inversion on mem_hotplug_lock and device_lock().
More details can be found in patch 3 and patch 6.
I propose the general rules (documentation added in patch 6):
1. add_memory/add_memory_resource() must only be called with
device_hotplug_lock.
2. remove_memory() must only be called with device_hotplug_lock. This is
already documented and holds for all callers.
3. device_online()/device_offline() must only be called with
device_hotplug_lock. This is already documented and true for now in core
code. Other callers (related to memory hotplug) have to be fixed up.
4. mem_hotplug_lock is taken inside of add_memory/remove_memory/
online_pages/offline_pages.
To me, this looks way cleaner than what we have right now (and easier to
verify). And looking at the documentation of remove_memory, using
lock_device_hotplug also for add_memory() feels natural.
This patch (of 6):
remove_memory() is exported right now but requires the
device_hotplug_lock, which is not exported. So let's provide a variant
that takes the lock and only export that one.
The lock is already held in
arch/powerpc/platforms/pseries/hotplug-memory.c
drivers/acpi/acpi_memhotplug.c
arch/powerpc/platforms/powernv/memtrace.c
Apart from that, there are not other users in the tree.
Link: http://lkml.kernel.org/r/20180925091457.28651-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Rashmica Gupta <rashmica.g@gmail.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After updating all memblock users to explicitly specify SMP_CACHE_BYTES
alignment rather than use 0, it is still possible that uncovered users may
sneak in. Add a WARN_ON_ONCE for such cases.
[sfr@canb.auug.org.au: use dump_stack() instead of WARN_ON_ONCE for the alignment checks]
Link: http://lkml.kernel.org/r/20181016131927.6ceba6ab@canb.auug.org.au
[akpm@linux-foundation.org: add apologetic comment]
Link: http://lkml.kernel.org/r/20181011060850.GA19822@rapoport-lnx
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a memblock allocation APIs are called with align = 0, the alignment
is implicitly set to SMP_CACHE_BYTES.
Implicit alignment is done deep in the memblock allocator and it can
come as a surprise. Not that such an alignment would be wrong even
when used incorrectly but it is better to be explicit for the sake of
clarity and the prinicple of the least surprise.
Replace all such uses of memblock APIs with the 'align' parameter
explicitly set to SMP_CACHE_BYTES and stop implicit alignment assignment
in the memblock internal allocation functions.
For the case when memblock APIs are used via helper functions, e.g. like
iommu_arena_new_node() in Alpha, the helper functions were detected with
Coccinelle's help and then manually examined and updated where
appropriate.
The direct memblock APIs users were updated using the semantic patch below:
@@
expression size, min_addr, max_addr, nid;
@@
(
|
- memblock_alloc_try_nid_raw(size, 0, min_addr, max_addr, nid)
+ memblock_alloc_try_nid_raw(size, SMP_CACHE_BYTES, min_addr, max_addr,
nid)
|
- memblock_alloc_try_nid_nopanic(size, 0, min_addr, max_addr, nid)
+ memblock_alloc_try_nid_nopanic(size, SMP_CACHE_BYTES, min_addr, max_addr,
nid)
|
- memblock_alloc_try_nid(size, 0, min_addr, max_addr, nid)
+ memblock_alloc_try_nid(size, SMP_CACHE_BYTES, min_addr, max_addr, nid)
|
- memblock_alloc(size, 0)
+ memblock_alloc(size, SMP_CACHE_BYTES)
|
- memblock_alloc_raw(size, 0)
+ memblock_alloc_raw(size, SMP_CACHE_BYTES)
|
- memblock_alloc_from(size, 0, min_addr)
+ memblock_alloc_from(size, SMP_CACHE_BYTES, min_addr)
|
- memblock_alloc_nopanic(size, 0)
+ memblock_alloc_nopanic(size, SMP_CACHE_BYTES)
|
- memblock_alloc_low(size, 0)
+ memblock_alloc_low(size, SMP_CACHE_BYTES)
|
- memblock_alloc_low_nopanic(size, 0)
+ memblock_alloc_low_nopanic(size, SMP_CACHE_BYTES)
|
- memblock_alloc_from_nopanic(size, 0, min_addr)
+ memblock_alloc_from_nopanic(size, SMP_CACHE_BYTES, min_addr)
|
- memblock_alloc_node(size, 0, nid)
+ memblock_alloc_node(size, SMP_CACHE_BYTES, nid)
)
[mhocko@suse.com: changelog update]
[akpm@linux-foundation.org: coding-style fixes]
[rppt@linux.ibm.com: fix missed uses of implicit alignment]
Link: http://lkml.kernel.org/r/20181016133656.GA10925@rapoport-lnx
Link: http://lkml.kernel.org/r/1538687224-17535-1-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Paul Burton <paul.burton@mips.com> [MIPS]
Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move remaining definitions and declarations from include/linux/bootmem.h
into include/linux/memblock.h and remove the redundant header.
The includes were replaced with the semantic patch below and then
semi-automated removal of duplicated '#include <linux/memblock.h>
@@
@@
- #include <linux/bootmem.h>
+ #include <linux/memblock.h>
[sfr@canb.auug.org.au: dma-direct: fix up for the removal of linux/bootmem.h]
Link: http://lkml.kernel.org/r/20181002185342.133d1680@canb.auug.org.au
[sfr@canb.auug.org.au: powerpc: fix up for removal of linux/bootmem.h]
Link: http://lkml.kernel.org/r/20181005161406.73ef8727@canb.auug.org.au
[sfr@canb.auug.org.au: x86/kaslr, ACPI/NUMA: fix for linux/bootmem.h removal]
Link: http://lkml.kernel.org/r/20181008190341.5e396491@canb.auug.org.au
Link: http://lkml.kernel.org/r/1536927045-23536-30-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The free_bootmem_late and memblock_free_late do exactly the same thing:
they iterate over a range and give pages to the page allocator.
Replace calls to free_bootmem_late with calls to memblock_free_late and
remove the bootmem variant.
Link: http://lkml.kernel.org/r/1536927045-23536-25-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The bootmem compatibility APIs are not used and can be removed.
Link: http://lkml.kernel.org/r/1536927045-23536-23-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With the align parameter memblock_alloc_node() can be used as drop in
replacement for alloc_bootmem_pages_node() and __alloc_bootmem_node(),
which is done in the following patches.
Link: http://lkml.kernel.org/r/1536927045-23536-15-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make it explicit that the caller gets a physical address rather than a
virtual one.
This will also allow using meblock_alloc prefix for memblock allocations
returning virtual address, which is done in the following patches.
The conversion is done using the following semantic patch:
@@
expression e1, e2, e3;
@@
(
- memblock_alloc(e1, e2)
+ memblock_phys_alloc(e1, e2)
|
- memblock_alloc_nid(e1, e2, e3)
+ memblock_phys_alloc_nid(e1, e2, e3)
|
- memblock_alloc_try_nid(e1, e2, e3)
+ memblock_phys_alloc_try_nid(e1, e2, e3)
)
Link: http://lkml.kernel.org/r/1536927045-23536-7-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All architectures have been converted to use MEMBLOCK + NO_BOOTMEM. The
bootmem allocator implementation can be removed.
Link: http://lkml.kernel.org/r/1536927045-23536-5-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All architecures use memblock for early memory management. There is no need
for the CONFIG_HAVE_MEMBLOCK configuration option.
[rppt@linux.vnet.ibm.com: of/fdt: fixup #ifdefs]
Link: http://lkml.kernel.org/r/20180919103457.GA20545@rapoport-lnx
[rppt@linux.vnet.ibm.com: csky: fixups after bootmem removal]
Link: http://lkml.kernel.org/r/20180926112744.GC4628@rapoport-lnx
[rppt@linux.vnet.ibm.com: remove stale #else and the code it protects]
Link: http://lkml.kernel.org/r/1538067825-24835-1-git-send-email-rppt@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1536927045-23536-4-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All achitectures select NO_BOOTMEM which essentially becomes 'Y' for any
kernel configuration and therefore it can be removed.
[alexander.h.duyck@linux.intel.com: remove now defunct NO_BOOTMEM from depends list for deferred init]
Link: http://lkml.kernel.org/r/20180925201814.3576.15105.stgit@localhost.localdomain
Link: http://lkml.kernel.org/r/1536927045-23536-3-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The concern here is that "gup->size" is a u64 and "nr_pages" is unsigned
long. On 32 bit systems we could trick the kernel into allocating fewer
pages than expected.
Link: http://lkml.kernel.org/r/20181025061546.hnhkv33diogf2uis@kili.mountain
Fixes: 64c349f4ae ("mm: add infrastructure for get_user_pages_fast() benchmarking")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Invalidate device page table at start of invalidation and invalidate in
progress CPU page table snapshooting at both start and end of any
invalidation.
This is helpful when device need to dirty page because the device page
table report the page as dirty. Dirtying page must happen in the start
mmu notifier callback and not in the end one.
Link: http://lkml.kernel.org/r/20181019160442.18723-7-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use a structure to gather all the parameters for the update callback.
This make it easier when adding new parameters by avoiding having to
update all callback function signature.
The hmm_update structure is always associated with a mmu_notifier
callbacks so we are not planing on grouping multiple updates together.
Nor do we care about page size for the range as range will over fully
cover the page being invalidated (this is a mmu_notifier property).
Link: http://lkml.kernel.org/r/20181019160442.18723-6-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Before this patch migration pmd entry (!pmd_present()) would have been
treated as a bad entry (pmd_bad() returns true on migration pmd entry).
The outcome was that device driver would believe that the range covered by
the pmd was bad and would either SIGBUS or simply kill all the device's
threads (each device driver decide how to react when the device tries to
access poisonnous or invalid range of memory).
This patch explicitly handle the case of migration pmd entry which are non
present pmd entry and either wait for the migration to finish or report
empty range (when device is just trying to pre- fill a range of virtual
address and thus do not want to wait or trigger page fault).
Link: http://lkml.kernel.org/r/20181019160442.18723-5-jglisse@redhat.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In hmm_mirror_unregister(), mm->hmm is set to NULL and then
mmu_notifier_unregister_no_release() is called. That creates a small
window where mmu_notifier can call mmu_notifier_ops with mm->hmm equal to
NULL. Fix this by first unregistering mmu notifier callbacks and then
setting mm->hmm to NULL.
Similarly in hmm_register(), set mm->hmm before registering mmu_notifier
callbacks so callback functions always see mm->hmm set.
Link: http://lkml.kernel.org/r/20181019160442.18723-4-jglisse@redhat.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Private ZONE_DEVICE pages use a special pte entry and thus are not
present. Properly handle this case in map_pte(), it is already handled in
check_pte(), the map_pte() part was lost in some rebase most probably.
Without this patch the slow migration path can not migrate back to any
private ZONE_DEVICE memory to regular memory. This was found after stress
testing migration back to system memory. This ultimatly can lead to the
CPU constantly page fault looping on the special swap entry.
Link: http://lkml.kernel.org/r/20181019160442.18723-3-jglisse@redhat.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "HMM updates, improvements and fixes", v2
Few fixes that only affect HMM users. Improve the synchronization call
back so that we match was other mmu_notifier listener do and add proper
support to the new blockable flags in the process.
For curious folks here are branches to leverage HMM in various existing
device drivers:
https://cgit.freedesktop.org/~glisse/linux/log/?h=hmm-nouveau-v01https://cgit.freedesktop.org/~glisse/linux/log/?h=hmm-radeon-v00https://cgit.freedesktop.org/~glisse/linux/log/?h=hmm-intel-v00
More to come (amd gpu, Mellanox, ...)
I expect more of the preparatory work for nouveau will be merge in 4.20
(like we have been doing since 4.16) and i will wait until this patchset
is upstream before pushing the patches that actualy make use of HMM (to
avoid complex tree inter-dependency).
This patch (of 6):
Somehow utf=8 must have been broken.
Link: http://lkml.kernel.org/r/20181019160442.18723-2-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Plumb in a remap flag that enables the filesystem remap handler to
shorten remapping requests for callers that can handle it. Now
copy_file_range can report partial success (in case we run up against
alignment problems, resource limits, etc.).
We also enable CAN_SHORTEN for fideduperange to maintain existing
userspace-visible behavior where xfs/btrfs shorten the dedupe range to
avoid stale post-eof data exposure.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Change the remap_file_range functions to take a number of bytes to
operate upon and return the number of bytes they operated on. This is a
requirement for allowing fs implementations to return short clone/dedupe
results to the user, which will enable us to obey resource limits in a
graceful manner.
A subsequent patch will enable copy_file_range to signal to the
->clone_file_range implementation that it can handle a short length,
which will be returned in the function's return value. For now the
short return is not implemented anywhere so the behavior won't change --
either copy_file_range manages to clone the entire range or it tries an
alternative.
Neither clone ioctl can take advantage of this, alas.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Pass the same remap flags to generic_remap_checks for consistency.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
File range remapping, if allowed to run past the destination file's EOF,
is an optimization on a regular file write. Regular file writes that
extend the file length are subject to various constraints which are not
checked by range cloning.
This is a correctness problem because we're never allowed to touch
ranges that the page cache can't support (s_maxbytes); we're not
supposed to deal with large offsets (MAX_NON_LFS) if O_LARGEFILE isn't
set; and we must obey resource limits (RLIMIT_FSIZE).
Therefore, add these checks to the new generic_remap_checks function so
that we curtail unexpected behavior.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Move the file range checks from vfs_clone_file_prep into a separate
generic_remap_checks function so that all the checks are collected in a
central location. This forms the basis for adding more checks from
generic_write_checks that will make cloning's input checking more
consistent with write input checking.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Pull XArray conversion from Matthew Wilcox:
"The XArray provides an improved interface to the radix tree data
structure, providing locking as part of the API, specifying GFP flags
at allocation time, eliminating preloading, less re-walking the tree,
more efficient iterations and not exposing RCU-protected pointers to
its users.
This patch set
1. Introduces the XArray implementation
2. Converts the pagecache to use it
3. Converts memremap to use it
The page cache is the most complex and important user of the radix
tree, so converting it was most important. Converting the memremap
code removes the only other user of the multiorder code, which allows
us to remove the radix tree code that supported it.
I have 40+ followup patches to convert many other users of the radix
tree over to the XArray, but I'd like to get this part in first. The
other conversions haven't been in linux-next and aren't suitable for
applying yet, but you can see them in the xarray-conv branch if you're
interested"
* 'xarray' of git://git.infradead.org/users/willy/linux-dax: (90 commits)
radix tree: Remove multiorder support
radix tree test: Convert multiorder tests to XArray
radix tree tests: Convert item_delete_rcu to XArray
radix tree tests: Convert item_kill_tree to XArray
radix tree tests: Move item_insert_order
radix tree test suite: Remove multiorder benchmarking
radix tree test suite: Remove __item_insert
memremap: Convert to XArray
xarray: Add range store functionality
xarray: Move multiorder_check to in-kernel tests
xarray: Move multiorder_shrink to kernel tests
xarray: Move multiorder account test in-kernel
radix tree test suite: Convert iteration test to XArray
radix tree test suite: Convert tag_tagged_items to XArray
radix tree: Remove radix_tree_clear_tags
radix tree: Remove radix_tree_maybe_preload_order
radix tree: Remove split/join code
radix tree: Remove radix_tree_update_node_t
page cache: Finish XArray conversion
dax: Convert page fault handlers to XArray
...
Some test systems were experiencing negative huge page reserve counts and
incorrect file block counts. This was traced to /proc/sys/vm/drop_caches
removing clean pages from hugetlbfs file pagecaches. When non-hugetlbfs
explicit code removes the pages, the appropriate accounting is not
performed.
This can be recreated as follows:
fallocate -l 2M /dev/hugepages/foo
echo 1 > /proc/sys/vm/drop_caches
fallocate -l 2M /dev/hugepages/foo
grep -i huge /proc/meminfo
AnonHugePages: 0 kB
ShmemHugePages: 0 kB
HugePages_Total: 2048
HugePages_Free: 2047
HugePages_Rsvd: 18446744073709551615
HugePages_Surp: 0
Hugepagesize: 2048 kB
Hugetlb: 4194304 kB
ls -lsh /dev/hugepages/foo
4.0M -rw-r--r--. 1 root root 2.0M Oct 17 20:05 /dev/hugepages/foo
To address this issue, dirty pages as they are added to pagecache. This
can easily be reproduced with fallocate as shown above. Read faulted
pages will eventually end up being marked dirty. But there is a window
where they are clean and could be impacted by code such as drop_caches.
So, just dirty them all as they are added to the pagecache.
Link: http://lkml.kernel.org/r/b5be45b8-5afe-56cd-9482-28384699a049@oracle.com
Fixes: 6bda666a03 ("hugepages: fold find_or_alloc_pages into huge_no_page()")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Mihcla Hocko <mhocko@suse.com>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Btrfs currently does not support swap files because swap's use of bmap
does not work with copy-on-write and multiple devices. See 35054394c4
("Btrfs: stop providing a bmap operation to avoid swapfile corruptions").
However, the swap code has a mechanism for the filesystem to manually add
swap extents using add_swap_extent() from the ->swap_activate() aop.
iomap has done this since 67482129cd ("iomap: add a swapfile activation
function"). Btrfs will do the same in a later patch, so export
add_swap_extent().
Link: http://lkml.kernel.org/r/bb1208575e02829aae51b538709476964f97b1ea.1536704650.git.osandov@fb.com
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Sterba <dsterba@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The SWP_FILE flag serves two purposes: to make swap_{read,write}page() go
through the filesystem, and to make swapoff() call ->swap_deactivate().
For Btrfs, we want the latter but not the former, so split this flag into
two. This makes us always call ->swap_deactivate() if ->swap_activate()
succeeded, not just if it didn't add any swap extents itself.
This also resolves the issue of the very misleading name of SWP_FILE,
which is only used for swap files over NFS.
Link: http://lkml.kernel.org/r/6d63d8668c4287a4f6d203d65696e96f80abdfc7.1536704650.git.osandov@fb.com
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There should be no cache left by the time we overwrite the old transhuge
pmd with the new one. It's already too late to flush through the virtual
address because we already copied the page data to the new physical
address.
So flush the cache before the data copy.
Also delete the "end" variable to shutoff a "unused variable" warning on
x86 where flush_cache_range() is a noop.
Link: http://lkml.kernel.org/r/20181015202311.7209-1-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
change_huge_pmd() after arming the numa/protnone pmd doesn't flush the TLB
right away. do_huge_pmd_numa_page() flushes the TLB before calling
migrate_misplaced_transhuge_page(). By the time do_huge_pmd_numa_page()
runs some CPU could still access the page through the TLB.
change_huge_pmd() before arming the numa/protnone transhuge pmd calls
mmu_notifier_invalidate_range_start(). So there's no need of
mmu_notifier_invalidate_range_start()/mmu_notifier_invalidate_range_only_end()
sequence in migrate_misplaced_transhuge_page() too, because by the time
migrate_misplaced_transhuge_page() runs, the pmd mapping has already been
invalidated in the secondary MMUs. It has to or if a secondary MMU can
still write to the page, the migrate_page_copy() would lose data.
However an explicit mmu_notifier_invalidate_range() is needed before
migrate_misplaced_transhuge_page() starts copying the data of the
transhuge page or the below can happen for MMU notifier users sharing the
primary MMU pagetables and only implementing ->invalidate_range:
CPU0 CPU1 GPU sharing linux pagetables using
only ->invalidate_range
----------- ------------ ---------
GPU secondary MMU writes to the page
mapped by the transhuge pmd
change_pmd_range()
mmu..._range_start()
->invalidate_range_start() noop
change_huge_pmd()
set_pmd_at(numa/protnone)
pmd_unlock()
do_huge_pmd_numa_page()
CPU TLB flush globally (1)
CPU cannot write to page
migrate_misplaced_transhuge_page()
GPU writes to the page...
migrate_page_copy()
...GPU stops writing to the page
CPU TLB flush (2)
mmu..._range_end() (3)
->invalidate_range_stop() noop
->invalidate_range()
GPU secondary MMU is invalidated
and cannot write to the page anymore
(too late)
Just like we need a CPU TLB flush (1) because the TLB flush (2) arrives
too late, we also need a mmu_notifier_invalidate_range() before calling
migrate_misplaced_transhuge_page(), because the ->invalidate_range() in
(3) also arrives too late.
This requirement is the result of the lazy optimization in
change_huge_pmd() that releases the pmd_lock without first flushing the
TLB and without first calling mmu_notifier_invalidate_range().
Even converting the removed mmu_notifier_invalidate_range_only_end() into
a mmu_notifier_invalidate_range_end() would not have been enough to fix
this, because it run after migrate_page_copy().
After the hugepage data copy is done migrate_misplaced_transhuge_page()
can proceed and call set_pmd_at without having to flush the TLB nor any
secondary MMUs because the secondary MMU invalidate, just like the CPU TLB
flush, has to happen before the migrate_page_copy() is called or it would
be a bug in the first place (and it was for drivers using
->invalidate_range()).
KVM is unaffected because it doesn't implement ->invalidate_range().
The standard PAGE_SIZEd migrate_misplaced_page is less accelerated and
uses the generic migrate_pages which transitions the pte from
numa/protnone to a migration entry in try_to_unmap_one() and flushes TLBs
and all mmu notifiers there before copying the page.
Link: http://lkml.kernel.org/r/20181013002430.698-3-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "migrate_misplaced_transhuge_page race conditions".
Aaron found a new instance of the THP MADV_DONTNEED race against
pmdp_clear_flush* variants, that was apparently left unfixed.
While looking into the race found by Aaron, I may have found two more
issues in migrate_misplaced_transhuge_page.
These race conditions would not cause kernel instability, but they'd
corrupt userland data or leave data non zero after MADV_DONTNEED.
I did only minor testing, and I don't expect to be able to reproduce this
(especially the lack of ->invalidate_range before migrate_page_copy,
requires the latest iommu hardware or infiniband to reproduce). The last
patch is noop for x86 and it needs further review from maintainers of
archs that implement flush_cache_range() (not in CC yet).
To avoid confusion, it's not the first patch that introduces the bug fixed
in the second patch, even before removing the
pmdp_huge_clear_flush_notify, that _notify suffix was called after
migrate_page_copy already run.
This patch (of 3):
This is a corollary of ced108037c ("thp: fix MADV_DONTNEED vs. numa
balancing race"), 58ceeb6bec ("thp: fix MADV_DONTNEED vs. MADV_FREE
race") and 5b7abeae3a ("thp: fix MADV_DONTNEED vs clear soft dirty
race).
When the above three fixes where posted Dave asked
https://lkml.kernel.org/r/929b3844-aec2-0111-fef7-8002f9d4e2b9@intel.com
but apparently this was missed.
The pmdp_clear_flush* in migrate_misplaced_transhuge_page() was introduced
in a54a407fbf ("mm: Close races between THP migration and PMD numa
clearing").
The important part of such commit is only the part where the page lock is
not released until the first do_huge_pmd_numa_page() finished disarming
the pagenuma/protnone.
The addition of pmdp_clear_flush() wasn't beneficial to such commit and
there's no commentary about such an addition either.
I guess the pmdp_clear_flush() in such commit was added just in case for
safety, but it ended up introducing the MADV_DONTNEED race condition found
by Aaron.
At that point in time nobody thought of such kind of MADV_DONTNEED race
conditions yet (they were fixed later) so the code may have looked more
robust by adding the pmdp_clear_flush().
This specific race condition won't destabilize the kernel, but it can
confuse userland because after MADV_DONTNEED the memory won't be zeroed
out.
This also optimizes the code and removes a superfluous TLB flush.
[akpm@linux-foundation.org: reflow comment to 80 cols, fix grammar and typo (beacuse)]
Link: http://lkml.kernel.org/r/20181013002430.698-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Aaron Tomlin <atomlin@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The static lock quarantine_lock is used in quarantine.c to protect the
quarantine queue datastructures. It is taken inside quarantine queue
manipulation routines (quarantine_put(), quarantine_reduce() and
quarantine_remove_cache()), with IRQs disabled. This is not a problem on
a stock kernel but is problematic on an RT kernel where spin locks are
sleeping spinlocks, which can sleep and can not be acquired with disabled
interrupts.
Convert the quarantine_lock to a raw spinlock_t. The usage of
quarantine_lock is confined to quarantine.c and the work performed while
the lock is held is used for debug purpose.
[bigeasy@linutronix.de: slightly altered the commit message]
Link: http://lkml.kernel.org/r/20181010214945.5owshc3mlrh74z4b@linutronix.de
Signed-off-by: Clark Williams <williams@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Getting pages from ZONE_DEVICE memory needs to check the backing device's
live-ness, which is tracked in the device's dev_pagemap metadata. This
metadata is stored in a radix tree and looking it up adds measurable
software overhead.
This patch avoids repeating this relatively costly operation when
dev_pagemap is used by caching the last dev_pagemap while getting user
pages. The gup_benchmark kernel self test reports this reduces time to
get user pages to as low as 1/3 of the previous time.
Link: http://lkml.kernel.org/r/20181012173040.15669-1-keith.busch@intel.com
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When checking for valid pfns in zero_resv_unavail(), it is not necessary
to verify that pfns within pageblock_nr_pages ranges are valid, only the
first one needs to be checked. This is because memory for pages are
allocated in contiguous chunks that contain pageblock_nr_pages struct
pages.
Link: http://lkml.kernel.org/r/20181002143821.5112-3-msys.mizuma@gmail.com
Signed-off-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Reviewed-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: Fix for movable_node boot option", v3.
This patch series contains a fix for the movable_node boot option issue
which was introduced by commit 124049decb ("x86/e820: put !E820_TYPE_RAM
regions into memblock.reserved").
The commit breaks the option because it changed the memory gap range to
reserved memblock. So, the node is marked as Normal zone even if the SRAT
has Hot pluggable affinity.
First and second patch fix the original issue which the commit tried to
fix, then revert the commit.
This patch (of 3):
There is a kernel panic that is triggered when reading /proc/kpageflags on
the kernel booted with kernel parameter 'memmap=nn[KMG]!ss[KMG]':
BUG: unable to handle kernel paging request at fffffffffffffffe
PGD 9b20e067 P4D 9b20e067 PUD 9b210067 PMD 0
Oops: 0000 [#1] SMP PTI
CPU: 2 PID: 1728 Comm: page-types Not tainted 4.17.0-rc6-mm1-v4.17-rc6-180605-0816-00236-g2dfb086ef02c+ #160
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.fc28 04/01/2014
RIP: 0010:stable_page_flags+0x27/0x3c0
Code: 00 00 00 0f 1f 44 00 00 48 85 ff 0f 84 a0 03 00 00 41 54 55 49 89 fc 53 48 8b 57 08 48 8b 2f 48 8d 42 ff 83 e2 01 48 0f 44 c7 <48> 8b 00 f6 c4 01 0f 84 10 03 00 00 31 db 49 8b 54 24 08 4c 89 e7
RSP: 0018:ffffbbd44111fde0 EFLAGS: 00010202
RAX: fffffffffffffffe RBX: 00007fffffffeff9 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000202 RDI: ffffed1182fff5c0
RBP: ffffffffffffffff R08: 0000000000000001 R09: 0000000000000001
R10: ffffbbd44111fed8 R11: 0000000000000000 R12: ffffed1182fff5c0
R13: 00000000000bffd7 R14: 0000000002fff5c0 R15: ffffbbd44111ff10
FS: 00007efc4335a500(0000) GS:ffff93a5bfc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffe CR3: 00000000b2a58000 CR4: 00000000001406e0
Call Trace:
kpageflags_read+0xc7/0x120
proc_reg_read+0x3c/0x60
__vfs_read+0x36/0x170
vfs_read+0x89/0x130
ksys_pread64+0x71/0x90
do_syscall_64+0x5b/0x160
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7efc42e75e23
Code: 09 00 ba 9f 01 00 00 e8 ab 81 f4 ff 66 2e 0f 1f 84 00 00 00 00 00 90 83 3d 29 0a 2d 00 00 75 13 49 89 ca b8 11 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 db d3 01 00 48 89 04 24
According to kernel bisection, this problem became visible due to commit
f7f99100d8 which changes how struct pages are initialized.
Memblock layout affects the pfn ranges covered by node/zone. Consider
that we have a VM with 2 NUMA nodes and each node has 4GB memory, and the
default (no memmap= given) memblock layout is like below:
MEMBLOCK configuration:
memory size = 0x00000001fff75c00 reserved size = 0x000000000300c000
memory.cnt = 0x4
memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0
memory[0x1] [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0
memory[0x2] [0x0000000100000000-0x000000013fffffff], 0x0000000040000000 bytes on node 0 flags: 0x0
memory[0x3] [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0
...
If you give memmap=1G!4G (so it just covers memory[0x2]),
the range [0x100000000-0x13fffffff] is gone:
MEMBLOCK configuration:
memory size = 0x00000001bff75c00 reserved size = 0x000000000300c000
memory.cnt = 0x3
memory[0x0] [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0
memory[0x1] [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0
memory[0x2] [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0
...
This causes shrinking node 0's pfn range because it is calculated by the
address range of memblock.memory. So some of struct pages in the gap
range are left uninitialized.
We have a function zero_resv_unavail() which does zeroing the struct pages
outside memblock.memory, but currently it covers only the reserved
unavailable range (i.e. memblock.memory && !memblock.reserved). This
patch extends it to cover all unavailable range, which fixes the reported
issue.
Link: http://lkml.kernel.org/r/20181002143821.5112-2-msys.mizuma@gmail.com
Fixes: f7f99100d8 ("mm: stop zeroing memory during allocation in vmemmap")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Tested-by: Oscar Salvador <osalvador@suse.de>
Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Provide new gup benchmark ioctl commands to run different user page
pinning methods, get_user_pages_longterm() and get_user_pages(), in
addition to the existing get_user_pages_fast().
Link: http://lkml.kernel.org/r/20181010195605.10689-2-keith.busch@intel.com
Signed-off-by: Keith Busch <keith.busch@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We'd like to measure time to unpin user pages, so this adds a second
benchmark timer on put_page, separate from get_page.
Adding the field breaks this ioctl ABI, but should be okay since this an
in-tree kernel selftest.
[akpm@linux-foundation.org: add expansion to struct gup_benchmark for future use]
Link: http://lkml.kernel.org/r/20181010195605.10689-1-keith.busch@intel.com
Signed-off-by: Keith Busch <keith.busch@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It was reported that on some of our machines containers were restarted
with OOM symptoms without an obvious reason. Despite there were almost no
memory pressure and plenty of page cache, MEMCG_OOM event was raised
occasionally, causing the container management software to think, that OOM
has happened. However, no tasks have been killed.
The following investigation showed that the problem is caused by a failing
attempt to charge a high-order page. In such case, the OOM killer is
never invoked. As shown below, it can happen under conditions, which are
very far from a real OOM: e.g. there is plenty of clean page cache and no
memory pressure.
There is no sense in raising an OOM event in this case, as it might
confuse a user and lead to wrong and excessive actions (e.g. restart the
workload, as in my case).
Let's look at the charging path in try_charge(). If the memory usage is
about memory.max, which is absolutely natural for most memory cgroups, we
try to reclaim some pages. Even if we were able to reclaim enough memory
for the allocation, the following check can fail due to a race with
another concurrent allocation:
if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
goto retry;
For regular pages the following condition will save us from triggering
the OOM:
if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
goto retry;
But for high-order allocation this condition will intentionally fail. The
reason behind is that we'll likely fall to regular pages anyway, so it's
ok and even preferred to return ENOMEM.
In this case the idea of raising MEMCG_OOM looks dubious.
Fix this by moving MEMCG_OOM raising to mem_cgroup_oom() after allocation
order check, so that the event won't be raised for high order allocations.
This change doesn't affect regular pages allocation and charging.
Link: http://lkml.kernel.org/r/20181004214050.7417-1-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We've recently seen a workload on XFS filesystems with a repeatable
deadlock between background writeback and a multi-process application
doing concurrent writes and fsyncs to a small range of a file.
range_cyclic
writeback Process 1 Process 2
xfs_vm_writepages
write_cache_pages
writeback_index = 2
cycled = 0
....
find page 2 dirty
lock Page 2
->writepage
page 2 writeback
page 2 clean
page 2 added to bio
no more pages
write()
locks page 1
dirties page 1
locks page 2
dirties page 1
fsync()
....
xfs_vm_writepages
write_cache_pages
start index 0
find page 1 towrite
lock Page 1
->writepage
page 1 writeback
page 1 clean
page 1 added to bio
find page 2 towrite
lock Page 2
page 2 is writeback
<blocks>
write()
locks page 1
dirties page 1
fsync()
....
xfs_vm_writepages
write_cache_pages
start index 0
!done && !cycled
sets index to 0, restarts lookup
find page 1 dirty
find page 1 towrite
lock Page 1
page 1 is writeback
<blocks>
lock Page 1
<blocks>
DEADLOCK because:
- process 1 needs page 2 writeback to complete to make
enough progress to issue IO pending for page 1
- writeback needs page 1 writeback to complete so process 2
can progress and unlock the page it is blocked on, then it
can issue the IO pending for page 2
- process 2 can't make progress until process 1 issues IO
for page 1
The underlying cause of the problem here is that range_cyclic writeback is
processing pages in descending index order as we hold higher index pages
in a structure controlled from above write_cache_pages(). The
write_cache_pages() caller needs to be able to submit these pages for IO
before write_cache_pages restarts writeback at mapping index 0 to avoid
wcp inverting the page lock/writeback wait order.
generic_writepages() is not susceptible to this bug as it has no private
context held across write_cache_pages() - filesystems using this
infrastructure always submit pages in ->writepage immediately and so there
is no problem with range_cyclic going back to mapping index 0.
However:
mpage_writepages() has a private bio context,
exofs_writepages() has page_collect
fuse_writepages() has fuse_fill_wb_data
nfs_writepages() has nfs_pageio_descriptor
xfs_vm_writepages() has xfs_writepage_ctx
All of these ->writepages implementations can hold pages under writeback
in their private structures until write_cache_pages() returns, and hence
they are all susceptible to this deadlock.
Also worth noting is that ext4 has it's own bastardised version of
write_cache_pages() and so it /may/ have an equivalent deadlock. I looked
at the code long enough to understand that it has a similar retry loop for
range_cyclic writeback reaching the end of the file and then promptly ran
away before my eyes bled too much. I'll leave it for the ext4 developers
to determine if their code is actually has this deadlock and how to fix it
if it has.
There's a few ways I can see avoid this deadlock. There's probably more,
but these are the first I've though of:
1. get rid of range_cyclic altogether
2. range_cyclic always stops at EOF, and we start again from
writeback index 0 on the next call into write_cache_pages()
2a. wcp also returns EAGAIN to ->writepages implementations to
indicate range cyclic has hit EOF. writepages implementations can
then flush the current context and call wpc again to continue. i.e.
lift the retry into the ->writepages implementation
3. range_cyclic uses trylock_page() rather than lock_page(), and it
skips pages it can't lock without blocking. It will already do this
for pages under writeback, so this seems like a no-brainer
3a. all non-WB_SYNC_ALL writeback uses trylock_page() to avoid
blocking as per pages under writeback.
I don't think #1 is an option - range_cyclic prevents frequently
dirtied lower file offset from starving background writeback of
rarely touched higher file offsets.
#2 is simple, and I don't think it will have any impact on
performance as going back to the start of the file implies an
immediate seek. We'll have exactly the same number of seeks if we
switch writeback to another inode, and then come back to this one
later and restart from index 0.
#2a is pretty much "status quo without the deadlock". Moving the
retry loop up into the wcp caller means we can issue IO on the
pending pages before calling wcp again, and so avoid locking or
waiting on pages in the wrong order. I'm not convinced we need to do
this given that we get the same thing from #2 on the next writeback
call from the writeback infrastructure.
#3 is really just a band-aid - it doesn't fix the access/wait
inversion problem, just prevents it from becoming a deadlock
situation. I'd prefer we fix the inversion, not sweep it under the
carpet like this.
#3a is really an optimisation that just so happens to include the
band-aid fix of #3.
So it seems that the simplest way to fix this issue is to implement
solution #2
Link: http://lkml.kernel.org/r/20181005054526.21507-1-david@fromorbit.com
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.de>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memmap_init_zone, is getting complex, because it is called from different
contexts: hotplug, and during boot, and also because it must handle some
architecture quirks. One of them is mirrored memory.
Move the code that decides whether to skip mirrored memory outside of
memmap_init_zone, into a separate function.
[pasha.tatashin@oracle.com: uninline overlap_memmap_init()]
Link: http://lkml.kernel.org/r/20180726193509.3326-4-pasha.tatashin@oracle.com
Link: http://lkml.kernel.org/r/20180724235520.10200-4-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
update_defer_init() should be called only when struct page is about to be
initialized. Because it counts number of initialized struct pages, but
there we may skip struct pages if there is some mirrored memory.
So move, update_defer_init() after checking for mirrored memory.
Also, rename update_defer_init() to defer_init() and reverse the return
boolean to emphasize that this is a boolean function, that tells that the
reset of memmap initialization should be deferred.
Make this function self-contained: do not pass number of already
initialized pages in this zone by using static counters.
I found this bug by reading the code. The effect is that fewer than
expected struct pages are initialized early in boot, and it is possible
that in some corner cases we may fail to boot when mirrored pages are
used. The deferred on demand code should somewhat mitigate this. But
this still brings some inconsistencies compared to when booting without
mirrored pages, so it is better to fix.
[pasha.tatashin@oracle.com: add comment about defer_init's lack of locking]
Link: http://lkml.kernel.org/r/20180726193509.3326-3-pasha.tatashin@oracle.com
[akpm@linux-foundation.org: make defer_init non-inline, __meminit]
Link: http://lkml.kernel.org/r/20180724235520.10200-3-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memmap_init is sometimes a macro sometimes a function based on
__HAVE_ARCH_MEMMAP_INIT. It is only a function on ia64. Make memmap_init
a weak function instead, and let ia64 redefine it.
Link: http://lkml.kernel.org/r/20180724235520.10200-2-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This will allow to use generic refcount_t interfaces to check counters
overflow instead of currently existing VM_BUG_ON(). The only difference
after the patch is VM_BUG_ON() may cause BUG(), while refcount_t fires
with WARN(). But this seems not to be significant here, since such the
problems are usually caught by syzbot with panic-on-warn enabled.
Link: http://lkml.kernel.org/r/153910718919.7006.13400779039257185427.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrea Parri <andrea.parri@amarulasolutions.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If move_freepages_block() returns 0 because !zone_spans_pfn(),
*num_movable can hold the value from the stack because it does not get
initialized in move_freepages().
Move the initialization to move_freepages_block() to guarantee the value
actually makes sense.
This currently doesn't affect its only caller where num_movable != NULL,
so no bug fix, but just more robust.
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1810051355490.212229@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace "fallthru" with a proper "fall through" annotation.
This fix is part of the ongoing efforts to enabling
-Wimplicit-fallthrough
Link: http://lkml.kernel.org/r/20181003105114.GA24423@embeddedor.com
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Having two gigantic arrays that must manually be kept in sync, including
ifdefs, isn't exactly robust. To make it easier to catch such issues in
the future, add a BUILD_BUG_ON().
Link: http://lkml.kernel.org/r/20181001143138.95119-3-jannh@google.com
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We clear the pte temporarily during read/modify/write update of the pte.
If we take a page fault while the pte is cleared, the application can get
SIGBUS. One such case is with remap_pfn_range without a backing
vm_ops->fault callback. do_fault will return SIGBUS in that case.
cpu 0 cpu1
mprotect()
ptep_modify_prot_start()/pte cleared.
.
. page fault.
.
.
prep_modify_prot_commit()
Fix this by taking page table lock and rechecking for pte_none.
[aneesh.kumar@linux.ibm.com: fix crash observed with syzkaller run]
Link: http://lkml.kernel.org/r/87va6bwlfg.fsf@linux.ibm.com
Link: http://lkml.kernel.org/r/20180926031858.9692-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ido Schimmel <idosch@idosch.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
brk might be used to shrink memory mapping too other than munmap(). So,
it may hold write mmap_sem for long time when shrinking large mapping, as
what commit ("mm: mmap: zap pages with read mmap_sem in munmap")
described.
The brk() will not manipulate vmas anymore after __do_munmap() call for
the mapping shrink use case. But, it may set mm->brk after __do_munmap(),
which needs hold write mmap_sem.
However, a simple trick can workaround this by setting mm->brk before
__do_munmap(). Then restore the original value if __do_munmap() fails.
With this trick, it is safe to downgrade to read mmap_sem.
So, the same optimization, which downgrades mmap_sem to read for zapping
pages, is also feasible and reasonable to this case.
The period of holding exclusive mmap_sem for shrinking large mapping would
be reduced significantly with this optimization.
[akpm@linux-foundation.org: tweak comment]
[yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue]
Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com
Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Other than munmap, mremap might be used to shrink memory mapping too.
So, it may hold write mmap_sem for long time when shrinking large
mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in
munmap") described.
The mremap() will not manipulate vmas anymore after __do_munmap() call for
the mapping shrink use case, so it is safe to downgrade to read mmap_sem.
So, the same optimization, which downgrades mmap_sem to read for zapping
pages, is also feasible and reasonable to this case.
The period of holding exclusive mmap_sem for shrinking large mapping
would be reduced significantly with this optimization.
MREMAP_FIXED and MREMAP_MAYMOVE are more complicated to adopt this
optimization since they need manipulate vmas after do_munmap(),
downgrading mmap_sem may create race window.
Simple mapping shrink is the low hanging fruit, and it may cover the
most cases of unmap with munmap together.
[akpm@linux-foundation.org: tweak comment]
[yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue]
Link: http://lkml.kernel.org/r/1538687672-17795-2-git-send-email-yang.shi@linux.alibaba.com
Link: http://lkml.kernel.org/r/1538067582-60038-1-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These codes can be replaced with new inline vmf_error().
Link: http://lkml.kernel.org/r/20180927171411.GA23331@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The local variable `addr' in __get_user_pages_fast() is just a shadow of
`start'. Since `start' never changes after assignment to `addr', it is
fine to replace `start' with it.
Also the meaning of [start, end] is more obvious than [addr, end] when
passed to gup_pgd_range().
Link: http://lkml.kernel.org/r/20180925021448.20265-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ZONE_DEVICE pages were being initialized in two locations. One was
with the memory_hotplug lock held and another was outside of that lock.
The problem with this is that it was nearly doubling the memory
initialization time. Instead of doing this twice, once while holding a
global lock and once without, I am opting to defer the initialization to
the one outside of the lock. This allows us to avoid serializing the
overhead for memory init and we can instead focus on per-node init times.
One issue I encountered is that devm_memremap_pages and
hmm_devmmem_pages_create were initializing only the pgmap field the same
way. One wasn't initializing hmm_data, and the other was initializing it
to a poison value. Since this is something that is exposed to the driver
in the case of hmm I am opting for a third option and just initializing
hmm_data to 0 since this is going to be exposed to unknown third party
drivers.
[alexander.h.duyck@linux.intel.com: fix reference count for pgmap in devm_memremap_pages]
Link: http://lkml.kernel.org/r/20181008233404.1909.37302.stgit@localhost.localdomain
Link: http://lkml.kernel.org/r/20180925202053.3576.66039.stgit@localhost.localdomain
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It doesn't make much sense to use the atomic SetPageReserved at init time
when we are using memset to clear the memory and manipulating the page
flags via simple "&=" and "|=" operations in __init_single_page.
This patch adds a non-atomic version __SetPageReserved that can be used
during page init and shows about a 10% improvement in initialization times
on the systems I have available for testing. On those systems I saw
initialization times drop from around 35 seconds to around 32 seconds to
initialize a 3TB block of persistent memory. I believe the main advantage
of this is that it allows for more compiler optimization as the __set_bit
operation can be reordered whereas the atomic version cannot.
I tried adding a bit of documentation based on f1dd2cd13c ("mm,
memory_hotplug: do not associate hotadded memory to zones until online").
Ideally the reserved flag should be set earlier since there is a brief
window where the page is initialization via __init_single_page and we have
not set the PG_Reserved flag. I'm leaving that for a future patch set as
that will require a more significant refactor.
Link: http://lkml.kernel.org/r/20180925202018.3576.11607.stgit@localhost.localdomain
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Address issues slowing persistent memory initialization", v5.
The main thing this patch set achieves is that it allows us to initialize
each node worth of persistent memory independently. As a result we reduce
page init time by about 2 minutes because instead of taking 30 to 40
seconds per node and going through each node one at a time, we process all
4 nodes in parallel in the case of a 12TB persistent memory setup spread
evenly over 4 nodes.
This patch (of 3):
On systems with a large amount of memory it can take a significant amount
of time to initialize all of the page structs with the PAGE_POISON_PATTERN
value. I have seen it take over 2 minutes to initialize a system with
over 12TB of RAM.
In order to work around the issue I had to disable CONFIG_DEBUG_VM and
then the boot time returned to something much more reasonable as the
arch_add_memory call completed in milliseconds versus seconds. However in
doing that I had to disable all of the other VM debugging on the system.
In order to work around a kernel that might have CONFIG_DEBUG_VM enabled
on a system that has a large amount of memory I have added a new kernel
parameter named "vm_debug" that can be set to "-" in order to disable it.
Link: http://lkml.kernel.org/r/20180925201921.3576.84239.stgit@localhost.localdomain
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The flag memcg_kmem_skip_account was added during the era of opt-out kmem
accounting. There is no need for such flag in the opt-in world as there
aren't any __GFP_ACCOUNT allocations within memcg_create_cache_enqueue().
Link: http://lkml.kernel.org/r/20180919004501.178023-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch, as the previous one, gets rid of the wrong if statements.
While at it, I realized that the comments are sometimes very confusing,
to say the least, and wrong.
For example:
___
zone_last = ZONE_MOVABLE;
/*
* check whether node_states[N_HIGH_MEMORY] will be changed
* If we try to offline the last present @nr_pages from the node,
* we can determind we will need to clear the node from
* node_states[N_HIGH_MEMORY].
*/
for (; zt <= zone_last; zt++)
present_pages += pgdat->node_zones[zt].present_pages;
if (nr_pages >= present_pages)
arg->status_change_nid = zone_to_nid(zone);
else
arg->status_change_nid = -1;
___
In case the node gets empry, it must be removed from N_MEMORY. We already
check N_HIGH_MEMORY a bit above within the CONFIG_HIGHMEM ifdef code. Not
to say that status_change_nid is for N_MEMORY, and not for N_HIGH_MEMORY.
So I re-wrote some of the comments to what I think is better.
[osalvador@suse.de: address feedback from Pavel]
Link: http://lkml.kernel.org/r/20180921132634.10103-5-osalvador@techadventures.net
Link: http://lkml.kernel.org/r/20180919100819.25518-6-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: <yasu.isimatu@gmail.com>
Cc: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While looking at node_states_check_changes_online, I stumbled upon some
confusing things.
Right after entering the function, we find this:
if (N_MEMORY == N_NORMAL_MEMORY)
zone_last = ZONE_MOVABLE;
This is wrong.
N_MEMORY cannot really be equal to N_NORMAL_MEMORY.
My guess is that this wanted to be something like:
if (N_NORMAL_MEMORY == N_HIGH_MEMORY)
to check if we have CONFIG_HIGHMEM.
Later on, in the CONFIG_HIGHMEM block, we have:
if (N_MEMORY == N_HIGH_MEMORY)
zone_last = ZONE_MOVABLE;
Again, this is wrong, and will never be evaluated to true.
Besides removing these wrong if statements, I simplified the function a
bit.
[osalvador@suse.de: address feedback from Pavel]
Link: http://lkml.kernel.org/r/20180921132634.10103-4-osalvador@techadventures.net
Link: http://lkml.kernel.org/r/20180919100819.25518-5-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <yasu.isimatu@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
node_states_clear has the following if statements:
if ((N_MEMORY != N_NORMAL_MEMORY) &&
(arg->status_change_nid_high >= 0))
...
if ((N_MEMORY != N_HIGH_MEMORY) &&
(arg->status_change_nid >= 0))
...
N_MEMORY can never be equal to neither N_NORMAL_MEMORY nor
N_HIGH_MEMORY.
Similar problem was found in [1].
Since this is wrong, let us get rid of it.
[1] https://patchwork.kernel.org/patch/10579155/
Link: http://lkml.kernel.org/r/20180919100819.25518-4-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <yasu.isimatu@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In node_states_check_changes_online, we check if the node will have to be
set for any of the N_*_MEMORY states after the pages have been onlined.
Later on, we perform the activation in node_states_set_node. Currently,
in node_states_set_node we set the node to N_MEMORY unconditionally.
This means that we call node_set_state for N_MEMORY every time pages go
online, but we only need to do it if the node has not yet been set for
N_MEMORY.
Fix this by checking status_change_nid.
Link: http://lkml.kernel.org/r/20180919100819.25518-2-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: <yasu.isimatu@gmail.com>
Cc: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the variable write_len instead of ov_iter_count(from).
Link: http://lkml.kernel.org/r/1537375855-2088-1-git-send-email-leviathan0992@gmail.com
Signed-off-by: haiqing.shq <leviathan0992@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When unmapping VM_PFNMAP mappings, vm flags need to be updated. Since the
vmas have been detached, so it sounds safe to update vm flags with read
mmap_sem.
Link: http://lkml.kernel.org/r/1537376621-51150-4-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When unmapping VM_HUGETLB mappings, vm flags need to be updated. Since
the vmas have been detached, so it sounds safe to update vm flags with
read mmap_sem.
Link: http://lkml.kernel.org/r/1537376621-51150-3-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: zap pages with read mmap_sem in munmap for large
mapping", v11.
Background:
Recently, when we ran some vm scalability tests on machines with large memory,
we ran into a couple of mmap_sem scalability issues when unmapping large memory
space, please refer to https://lkml.org/lkml/2017/12/14/733 and
https://lkml.org/lkml/2018/2/20/576.
History:
Then akpm suggested to unmap large mapping section by section and drop mmap_sem
at a time to mitigate it (see https://lkml.org/lkml/2018/3/6/784).
V1 patch series was submitted to the mailing list per Andrew's suggestion
(see https://lkml.org/lkml/2018/3/20/786). Then I received a lot great
feedback and suggestions.
Then this topic was discussed on LSFMM summit 2018. In the summit, Michal
Hocko suggested (also in the v1 patches review) to try "two phases"
approach. Zapping pages with read mmap_sem, then doing via cleanup with
write mmap_sem (for discussion detail, see
https://lwn.net/Articles/753269/)
Approach:
Zapping pages is the most time consuming part, according to the suggestion from
Michal Hocko [1], zapping pages can be done with holding read mmap_sem, like
what MADV_DONTNEED does. Then re-acquire write mmap_sem to cleanup vmas.
But, we can't call MADV_DONTNEED directly, since there are two major drawbacks:
* The unexpected state from PF if it wins the race in the middle of munmap.
It may return zero page, instead of the content or SIGSEGV.
* Can't handle VM_LOCKED | VM_HUGETLB | VM_PFNMAP and uprobe mappings, which
is a showstopper from akpm
But, some part may need write mmap_sem, for example, vma splitting. So,
the design is as follows:
acquire write mmap_sem
lookup vmas (find and split vmas)
deal with special mappings
detach vmas
downgrade_write
zap pages
free page tables
release mmap_sem
The vm events with read mmap_sem may come in during page zapping, but
since vmas have been detached before, they, i.e. page fault, gup, etc,
will not be able to find valid vma, then just return SIGSEGV or -EFAULT as
expected.
If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special
mappings. They will be handled by falling back to regular do_munmap()
with exclusive mmap_sem held in this patch since they may update vm flags.
But, with the "detach vmas first" approach, the vmas have been detached
when vm flags are updated, so it sounds safe to update vm flags with read
mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be
handled by using the optimized path in the following separate patches for
bisectable sake.
Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES).
However it is fine to have false-positive MMF_RECALC_UPROBES according to
uprobes developer. So, uprobe unmap will not be handled by the regular
path.
With the "detach vmas first" approach we don't have to re-acquire mmap_sem
again to clean up vmas to avoid race window which might get the address
space changed since downgrade_write() doesn't release the lock to lead
regression, which simply downgrades to read lock.
And, since the lock acquire/release cost is managed to the minimum and
almost as same as before, the optimization could be extended to any size
of mapping without incurring significant penalty to small mappings.
For the time being, just do this in munmap syscall path. Other
vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain
intact due to some implementation difficulties since they acquire write
mmap_sem from very beginning and hold it until the end, do_munmap() might
be called in the middle. But, the optimized do_munmap would like to be
called without mmap_sem held so that we can do the optimization. So, if
we want to do the similar optimization for mmap/mremap path, I'm afraid we
would have to redesign them. mremap might be called on very large area
depending on the usecases, the optimization to it will be considered in
the future.
This patch (of 3):
When running some mmap/munmap scalability tests with large memory (i.e.
> 300GB), the below hung task issue may happen occasionally.
INFO: task ps:14018 blocked for more than 120 seconds.
Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
message.
ps D 0 14018 1 0x00000004
ffff885582f84000 ffff885e8682f000 ffff880972943000 ffff885ebf499bc0
ffff8828ee120000 ffffc900349bfca8 ffffffff817154d0 0000000000000040
00ffffff812f872a ffff885ebf499bc0 024000d000948300 ffff880972943000
Call Trace:
[<ffffffff817154d0>] ? __schedule+0x250/0x730
[<ffffffff817159e6>] schedule+0x36/0x80
[<ffffffff81718560>] rwsem_down_read_failed+0xf0/0x150
[<ffffffff81390a28>] call_rwsem_down_read_failed+0x18/0x30
[<ffffffff81717db0>] down_read+0x20/0x40
[<ffffffff812b9439>] proc_pid_cmdline_read+0xd9/0x4e0
[<ffffffff81253c95>] ? do_filp_open+0xa5/0x100
[<ffffffff81241d87>] __vfs_read+0x37/0x150
[<ffffffff812f824b>] ? security_file_permission+0x9b/0xc0
[<ffffffff81242266>] vfs_read+0x96/0x130
[<ffffffff812437b5>] SyS_read+0x55/0xc0
[<ffffffff8171a6da>] entry_SYSCALL_64_fastpath+0x1a/0xc5
It is because munmap holds mmap_sem exclusively from very beginning to all
the way down to the end, and doesn't release it in the middle. When
unmapping large mapping, it may take long time (take ~18 seconds to unmap
320GB mapping with every single page mapped on an idle machine).
Zapping pages is the most time consuming part, according to the suggestion
from Michal Hocko [1], zapping pages can be done with holding read
mmap_sem, like what MADV_DONTNEED does. Then re-acquire write mmap_sem to
cleanup vmas.
But, some part may need write mmap_sem, for example, vma splitting. So,
the design is as follows:
acquire write mmap_sem
lookup vmas (find and split vmas)
deal with special mappings
detach vmas
downgrade_write
zap pages
free page tables
release mmap_sem
The vm events with read mmap_sem may come in during page zapping, but
since vmas have been detached before, they, i.e. page fault, gup, etc,
will not be able to find valid vma, then just return SIGSEGV or -EFAULT as
expected.
If the vma has VM_HUGETLB | VM_PFNMAP, they are considered as special
mappings. They will be handled by without downgrading mmap_sem in this
patch since they may update vm flags.
But, with the "detach vmas first" approach, the vmas have been detached
when vm flags are updated, so it sounds safe to update vm flags with read
mmap_sem for this specific case. So, VM_HUGETLB and VM_PFNMAP will be
handled by using the optimized path in the following separate patches for
bisectable sake.
Unmapping uprobe areas may need update mm flags (MMF_RECALC_UPROBES).
However it is fine to have false-positive MMF_RECALC_UPROBES according to
uprobes developer.
With the "detach vmas first" approach we don't have to re-acquire mmap_sem
again to clean up vmas to avoid race window which might get the address
space changed since downgrade_write() doesn't release the lock to lead
regression, which simply downgrades to read lock.
And, since the lock acquire/release cost is managed to the minimum and
almost as same as before, the optimization could be extended to any size
of mapping without incurring significant penalty to small mappings.
For the time being, just do this in munmap syscall path. Other
vm_munmap() or do_munmap() call sites (i.e mmap, mremap, etc) remain
intact due to some implementation difficulties since they acquire write
mmap_sem from very beginning and hold it until the end, do_munmap() might
be called in the middle. But, the optimized do_munmap would like to be
called without mmap_sem held so that we can do the optimization. So, if
we want to do the similar optimization for mmap/mremap path, I'm afraid we
would have to redesign them. mremap might be called on very large area
depending on the usecases, the optimization to it will be considered in
the future.
With the patches, exclusive mmap_sem hold time when munmap a 80GB address
space on a machine with 32 cores of E5-2680 @ 2.70GHz dropped to us level
from second.
munmap_test-15002 [008] 594.380138: funcgraph_entry: |
__vm_munmap() {
munmap_test-15002 [008] 594.380146: funcgraph_entry: !2485684 us
| unmap_region();
munmap_test-15002 [008] 596.865836: funcgraph_exit: !2485692 us
| }
Here the execution time of unmap_region() is used to evaluate the time of
holding read mmap_sem, then the remaining time is used with holding
exclusive lock.
[1] https://lwn.net/Articles/753269/
Link: http://lkml.kernel.org/r/1537376621-51150-2-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>Suggested-by: Michal Hocko <mhocko@kernel.org>
Suggested-by: Kirill A. Shutemov <kirill@shutemov.name>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vfree() might sleep if called not in interrupt context. Explain that in
the comment.
Link: http://lkml.kernel.org/r/20180914130512.10394-2-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vfree() might sleep if called not in interrupt context. So does kvfree()
too. Fix misleading kvfree()'s comment about allowed context.
Link: http://lkml.kernel.org/r/20180914130512.10394-1-aryabinin@virtuozzo.com
Fixes: 04b8e94607 ("mm/util.c: improve kvfree() kerneldoc")
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
