The transparent_hugepage_active() was introduced to show THP eligibility
bit in smaps in proc, smaps is the only user. But it actually does the
similar check as hugepage_vma_check() which is used by khugepaged. We
definitely don't have to maintain two similar checks, so kill
transparent_hugepage_active().
This patch also fixed the wrong behavior for VM_NO_KHUGEPAGED vmas.
Also move hugepage_vma_check() to huge_memory.c and huge_mm.h since it
is not only for khugepaged anymore.
[akpm@linux-foundation.org: check vma->vm_mm, per Zach]
[akpm@linux-foundation.org: add comment to vdso check]
Link: https://lkml.kernel.org/r/20220616174840.1202070-5-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The hugepage_vma_revalidate() needs to check if the vma is still anonymous
vma or not since the address may be unmapped then remapped to file before
khugepaged reaquired the mmap_lock.
The old comment is not quite helpful, elaborate this with better comment.
Link: https://lkml.kernel.org/r/20220616174840.1202070-4-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There are couple of places that check whether the vma size is ok for THP
or whether address fits, they are open coded and duplicate, use
transhuge_vma_suitable() to do the job by passing in (vma->end -
HPAGE_PMD_SIZE).
Move vma size check into hugepage_vma_check(). This will make
khugepaged_enter() is as same as khugepaged_enter_vma(). There is just
one caller for khugepaged_enter(), replace it to khugepaged_enter_vma()
and remove khugepaged_enter().
Link: https://lkml.kernel.org/r/20220616174840.1202070-3-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Cleanup transhuge_xxx helpers", v5.
This series is the follow-up of the discussion about cleaning up
transhuge_xxx helpers at
https://lore.kernel.org/linux-mm/627a71f8-e879-69a5-ceb3-fc8d29d2f7f1@suse.cz/.
THP has a bunch of helpers that do VMA sanity check for different paths,
they do the similar checks for the most callsites and have a lot duplicate
codes. And it is confusing what helpers should be used at what
conditions.
This series reorganized and cleaned up the code so that we could
consolidate all the checks into hugepage_vma_check().
The transhuge_vma_enabled(), transparent_hugepage_active() and
__transparent_hugepage_enabled() are killed by this series.
This patch (of 7):
Currently the THP flag check in hugepage_vma_check() will fallthrough if
the flag is NEVER and VM_HUGEPAGE is set. This is not a problem for now
since all the callers have the flag checked before or can't be invoked if
the flag is NEVER.
However, the following patch will call hugepage_vma_check() in more
places, for example, page fault, so this flag must be checked in
hugepge_vma_check().
Link: https://lkml.kernel.org/r/20220616174840.1202070-1-shy828301@gmail.com
Link: https://lkml.kernel.org/r/20220616174840.1202070-2-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
With DEVICE_COHERENT, we'll soon have vm_normal_pages() return
device-managed anonymous pages that are not LRU pages. Although they
behave like normal pages for purposes of mapping in CPU page, and for COW.
They do not support LRU lists, NUMA migration or THP.
Callers to follow_page() currently don't expect ZONE_DEVICE pages,
however, with DEVICE_COHERENT we might now return ZONE_DEVICE. Check for
ZONE_DEVICE pages in applicable users of follow_page() as well.
Link: https://lkml.kernel.org/r/20220715150521.18165-5-alex.sierra@amd.com
Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com> [v2]
Reviewed-by: Alistair Popple <apopple@nvidia.com> [v6]
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Transhuge swapcaches won't be freed in __collapse_huge_page_copy(). It's
because release_pte_page() is not called for these pages and thus
free_page_and_swap_cache can't grab the page lock. These pages won't be
freed from swap cache even if we are the only user until next time
reclaim. It shouldn't hurt indeed, but we could try to free these pages
to save more memory for system.
Link: https://lkml.kernel.org/r/20220625092816.4856-8-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The return value of khugepaged_add_pte_mapped_thp() is always 0 and also
ignored. Remove it to clean up the code.
Link: https://lkml.kernel.org/r/20220625092816.4856-7-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
nr_none is always 0 for non-shmem case because the page can be read from
the backend store. So when nr_none ! = 0, it must be in is_shmem case.
Also only adjust the nrpages and uncharge shmem when nr_none != 0 to save
cpu cycles.
Link: https://lkml.kernel.org/r/20220625092816.4856-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Fix some typos and tweak the code to meet codestyle. No functional change
intended.
Link: https://lkml.kernel.org/r/20220625092816.4856-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When do_swap_page returns VM_FAULT_RETRY, we do not retry here and thus
swap entry will remain in pagetable. This will result in later failure.
So stop swapping in pages in this case to save cpu cycles. As A further
optimization, mmap_lock is released when __collapse_huge_page_swapin()
fails to avoid relocking mmap_lock. And "swapped_in++" is moved after
error handling to make it more accurate.
Link: https://lkml.kernel.org/r/20220625092816.4856-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "A few cleanup patches for khugepaged", v2.
This series contains a few cleaup patches to remove unneeded return value,
use helper macro, fix typos and so on. More details can be found in the
respective changelogs.
This patch (of 7):
If we reach here, khugepaged_scan_mm_slot() has already made sure that
hugepage is enabled for shmem, via its call to hugepage_vma_check().
Remove this duplicated check.
Link: https://lkml.kernel.org/r/20220625092816.4856-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20220625092816.4856-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Howells <dhowells@redhat.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The khugepaged_enter_vma_merge() actually does as the same thing as the
khugepaged_enter() section called by shmem_mmap(), so consolidate them
into one helper and rename it to khugepaged_enter_vma().
Link: https://lkml.kernel.org/r/20220510203222.24246-8-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastmil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <song@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The hugepage_vma_check() could be reused by khugepaged_enter() and
khugepaged_enter_vma_merge(), but it is static in khugepaged.c. Make it
non-static and declare it in khugepaged.h.
Link: https://lkml.kernel.org/r/20220510203222.24246-7-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <song@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The most callers of khugepaged_enter() don't care about the return value.
Only dup_mmap(), anonymous THP page fault and MADV_HUGEPAGE handle the
error by returning -ENOMEM. Actually it is not harmful for them to ignore
the error case either. It also sounds overkilling to fail fork() and page
fault early due to khugepaged_enter() error, and MADV_HUGEPAGE does set
VM_HUGEPAGE flag regardless of the error.
Link: https://lkml.kernel.org/r/20220510203222.24246-6-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Vlastmil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since commit a4aeaa06d4 ("mm: khugepaged: skip huge page collapse for
special files"), khugepaged just collapses THP for regular file which is
the intended usecase for readonly fs THP. Only show regular file as THP
eligible accordingly.
And make file_thp_enabled() available for khugepaged too in order to
remove duplicate code.
Link: https://lkml.kernel.org/r/20220510203222.24246-5-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Vlastmil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The DAX vma may be seen by khugepaged when the mm has other khugepaged
suitable vmas. So khugepaged may try to collapse THP for DAX vma, but it
will fail due to page sanity check, for example, page is not on LRU.
So it is not harmful, but it is definitely pointless to run khugepaged
against DAX vma, so skip it in early check.
Link: https://lkml.kernel.org/r/20220510203222.24246-4-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Vlastmil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The hugepage_vma_check() called by khugepaged_enter_vma_merge() does check
VM_NO_KHUGEPAGED. Remove the check from caller and move the check in
hugepage_vma_check() up.
More checks may be run for VM_NO_KHUGEPAGED vmas, but MADV_HUGEPAGE is
definitely not a hot path, so cleaner code does outweigh.
Link: https://lkml.kernel.org/r/20220510203222.24246-3-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Vlastmil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When we're trying to collapse a 2M huge shmem page, don't retract pgtable
pmd page if it's registered with uffd-wp, because that pgtable could have
pte markers installed. Recycling of that pgtable means we'll lose the pte
markers. That could cause data loss for an uffd-wp enabled application on
shmem.
Instead of disabling khugepaged on these files, simply skip retracting
these special VMAs, then the page cache can still be merged into a huge
thp, and other mm/vma can still map the range of file with a huge thp when
proper.
Note that checking VM_UFFD_WP needs to be done with mmap_sem held for
write, that avoids race like:
khugepaged user thread
========== ===========
check VM_UFFD_WP, not set
UFFDIO_REGISTER with uffd-wp on shmem
wr-protect some pages (install markers)
take mmap_sem write lock
erase pmd and free pmd page
--> pte markers are dropped unnoticed!
Link: https://lkml.kernel.org/r/20220405014921.14994-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
New anonymous pages are always mapped natively: only THP/khugepaged code
maps a new compound anonymous page and passes "true". Otherwise, we're
just dealing with simple, non-compound pages.
Let's give the interface clearer semantics and document these. Remove the
PageTransCompound() sanity check from page_add_new_anon_rmap().
Link: https://lkml.kernel.org/r/20220428083441.37290-9-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Oded Gabbay <oded.gabbay@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Clean up the vma->vm_ops usage. Use vma_is_anonymous instead of
vma->vm_ops to make it more understandable.
Link: https://lkml.kernel.org/r/20220424071642.3234971-1-xu.xin16@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
reuse_swap_page() currently indicates if we can write to an anon page
without COW. A COW is required if the page is shared by multiple
processes (either already mapped or via swap entries) or if there is
concurrent writeback that cannot tolerate concurrent page modifications.
However, in the context of khugepaged we're not actually going to write to
a read-only mapped page, we'll copy the page content to our newly
allocated THP and map that THP writable. All we have to make sure is that
the read-only mapped page we're about to copy won't get reused by another
process sharing the page, otherwise, page content would get modified. But
that is already guaranteed via multiple mechanisms (e.g., holding a
reference, holding the page lock, removing the rmap after copying the
page).
The swapcache handling was introduced in commit 10359213d0 ("mm:
incorporate read-only pages into transparent huge pages") and it sounds
like it merely wanted to mimic what do_swap_page() would do when trying to
map a page obtained via the swapcache writable.
As that logic is unnecessary, let's just remove it, removing the last user
of reuse_swap_page().
Link: https://lkml.kernel.org/r/20220131162940.210846-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
collapse_file() is using unmap_mapping_pages(1) on each small page found
mapped, unlike others (reclaim, migration, splitting, memory-failure) who
use try_to_unmap(). There are four advantages to try_to_unmap(): first,
its TTU_IGNORE_MLOCK option now avoids leaving mlocked page in pagevec;
second, its vma lookup uses i_mmap_lock_read() not i_mmap_lock_write();
third, it breaks out early if page is not mapped everywhere it might be;
fourth, its TTU_BATCH_FLUSH option can be used, as in page reclaim, to
save up all the TLB flushing until all of the pages have been unmapped.
Wild guess: perhaps it was originally written to use try_to_unmap(),
but hit the VM_BUG_ON_PAGE(page_mapped) after unmapping, because without
TTU_SYNC it may skip page table locks; but unmap_mapping_pages() never
skips them, so fixed the issue. I did once hit that VM_BUG_ON_PAGE()
since making this change: we could pass TTU_SYNC here, but I think just
delete the check - the race is very rare, this is an ordinary small page
so we don't need to be so paranoid about mapcount surprises, and the
page_ref_freeze() just below already handles the case adequately.
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Add vma argument to mlock_vma_page() and munlock_vma_page(), make them
inline functions which check (vma->vm_flags & VM_LOCKED) before calling
mlock_page() and munlock_page() in mm/mlock.c.
Add bool compound to mlock_vma_page() and munlock_vma_page(): this is
because we have understandable difficulty in accounting pte maps of THPs,
and if passed a PageHead page, mlock_page() and munlock_page() cannot
tell whether it's a pmd map to be counted or a pte map to be ignored.
Add vma arg to page_add_file_rmap() and page_remove_rmap(), like the
others, and use that to call mlock_vma_page() at the end of the page
adds, and munlock_vma_page() at the end of page_remove_rmap() (end or
beginning? unimportant, but end was easier for assertions in testing).
No page lock is required (although almost all adds happen to hold it):
delete the "Serialize with page migration" BUG_ON(!PageLocked(page))s.
Certainly page lock did serialize with page migration, but I'm having
difficulty explaining why that was ever important.
Mlock accounting on THPs has been hard to define, differed between anon
and file, involved PageDoubleMap in some places and not others, required
clear_page_mlock() at some points. Keep it simple now: just count the
pmds and ignore the ptes, there is no reason for ptes to undo pmd mlocks.
page_add_new_anon_rmap() callers unchanged: they have long been calling
lru_cache_add_inactive_or_unevictable(), which does its own VM_LOCKED
handling (it also checks for not VM_SPECIAL: I think that's overcautious,
and inconsistent with other checks, that mmap_region() already prevents
VM_LOCKED on VM_SPECIAL; but haven't quite convinced myself to change it).
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
syzbot detected a case where the page table counters were not properly
updated.
syzkaller login: ------------[ cut here ]------------
kernel BUG at mm/page_table_check.c:162!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 3099 Comm: pasha Not tainted 5.16.0+ #48
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIO4
RIP: 0010:__page_table_check_zero+0x159/0x1a0
Call Trace:
free_pcp_prepare+0x3be/0xaa0
free_unref_page+0x1c/0x650
free_compound_page+0xec/0x130
free_transhuge_page+0x1be/0x260
__put_compound_page+0x90/0xd0
release_pages+0x54c/0x1060
__pagevec_release+0x7c/0x110
shmem_undo_range+0x85e/0x1250
...
The repro involved having a huge page that is split due to uprobe event
temporarily replacing one of the pages in the huge page. Later the huge
page was combined again, but the counters were off, as the PTE level was
not properly updated.
Make sure that when PMD is cleared and prior to freeing the level the
PTEs are updated.
Link: https://lkml.kernel.org/r/20220131203249.2832273-5-pasha.tatashin@soleen.com
Fixes: df4e817b71 ("mm: page table check")
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Paul Turner <pjt@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Unify the code that flushes, clears pmd entry, and frees the PTE table
level into a new function collapse_and_free_pmd().
This cleanup is useful as in the next patch we will add another call to
this function to iterate through PTE prior to freeing the level for page
table check.
Link: https://lkml.kernel.org/r/20220131203249.2832273-4-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Paul Turner <pjt@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge misc updates from Andrew Morton:
"146 patches.
Subsystems affected by this patch series: kthread, ia64, scripts,
ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak,
dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap,
memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb,
userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp,
ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and
damon)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (146 commits)
mm/damon: hide kernel pointer from tracepoint event
mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log
mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging
mm/damon/dbgfs: remove an unnecessary variable
mm/damon: move the implementation of damon_insert_region to damon.h
mm/damon: add access checking for hugetlb pages
Docs/admin-guide/mm/damon/usage: update for schemes statistics
mm/damon/dbgfs: support all DAMOS stats
Docs/admin-guide/mm/damon/reclaim: document statistics parameters
mm/damon/reclaim: provide reclamation statistics
mm/damon/schemes: account how many times quota limit has exceeded
mm/damon/schemes: account scheme actions that successfully applied
mm/damon: remove a mistakenly added comment for a future feature
Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning
Docs/admin-guide/mm/damon/usage: remove redundant information
Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks
mm/damon: convert macro functions to static inline functions
mm/damon: modify damon_rand() macro to static inline function
mm/damon: move damon_rand() definition into damon.h
...
There are interfaces to adjust max_ptes_none, max_ptes_swap,
max_ptes_shared values, see
/sys/kernel/mm/transparent_hugepage/khugepaged/.
But system administrator may not know which value is the best. So Add
those events to support adjusting max_ptes_* to suitable values.
For example, if default max_ptes_swap value causes too much failures,
and system uses zram whose IO is fast, administrator could increase
max_ptes_swap until THP_SCAN_EXCEED_SWAP_PTE not increase anymore.
Link: https://lkml.kernel.org/r/20211225094036.574157-1-yang.yang29@zte.com.cn
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Saravanan D <saravanand@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
None of the callers care about the total_map_swapcount() any more.
Link: https://lkml.kernel.org/r/20211220205943.456187-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have ptep_get_and_clear() and ptep_get_and_clear_full() helpers to
clear PTE from user page tables, but there is no variant for simple
clear of a present PTE from user page tables without using a low level
pte_clear() which can be either native or para-virtualised.
Add a new ptep_clear() that can be used in common code to clear PTEs
from page table. We will need this call later in order to add a hook
for page table check.
Link: https://lkml.kernel.org/r/20211221154650.1047963-3-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wei Xu <weixugc@google.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We currently store large folios as 2^N consecutive entries. While this
consumes rather more memory than necessary, it also turns out to be buggy.
A writeback operation which starts within a tail page of a dirty folio will
not write back the folio as the xarray's dirty bit is only set on the
head index. With multi-index entries, the dirty bit will be found no
matter where in the folio the operation starts.
This does end up simplifying the page cache slightly, although not as
much as I had hoped.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Merge misc updates from Andrew Morton:
"257 patches.
Subsystems affected by this patch series: scripts, ocfs2, vfs, and
mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache,
gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc,
pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools,
memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm,
vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram,
cleanups, kfence, and damon)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits)
mm/damon: remove return value from before_terminate callback
mm/damon: fix a few spelling mistakes in comments and a pr_debug message
mm/damon: simplify stop mechanism
Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions
Docs/admin-guide/mm/damon/start: simplify the content
Docs/admin-guide/mm/damon/start: fix a wrong link
Docs/admin-guide/mm/damon/start: fix wrong example commands
mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on
mm/damon: remove unnecessary variable initialization
Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM
mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM)
selftests/damon: support watermarks
mm/damon/dbgfs: support watermarks
mm/damon/schemes: activate schemes based on a watermarks mechanism
tools/selftests/damon: update for regions prioritization of schemes
mm/damon/dbgfs: support prioritization weights
mm/damon/vaddr,paddr: support pageout prioritization
mm/damon/schemes: prioritize regions within the quotas
mm/damon/selftests: support schemes quotas
mm/damon/dbgfs: support quotas of schemes
...
When initializing transparent huge pages, min_free_kbytes would be
calculated according to what khugepaged expected.
So when transparent huge pages get disabled, min_free_kbytes should be
recalculated instead of the higher value set by khugepaged.
Link: https://lkml.kernel.org/r/1633937809-16558-1-git-send-email-liangcaifan19@gmail.com
Signed-off-by: Liangcai Fan <liangcaifan19@gmail.com>
Signed-off-by: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add memory folios, a new type to represent either order-0 pages or
the head page of a compound page. This should be enough infrastructure
to support filesystems converting from pages to folios.
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Merge tag 'folio-5.16' of git://git.infradead.org/users/willy/pagecache
Pull memory folios from Matthew Wilcox:
"Add memory folios, a new type to represent either order-0 pages or the
head page of a compound page. This should be enough infrastructure to
support filesystems converting from pages to folios.
The point of all this churn is to allow filesystems and the page cache
to manage memory in larger chunks than PAGE_SIZE. The original plan
was to use compound pages like THP does, but I ran into problems with
some functions expecting only a head page while others expect the
precise page containing a particular byte.
The folio type allows a function to declare that it's expecting only a
head page. Almost incidentally, this allows us to remove various calls
to VM_BUG_ON(PageTail(page)) and compound_head().
This converts just parts of the core MM and the page cache. For 5.17,
we intend to convert various filesystems (XFS and AFS are ready; other
filesystems may make it) and also convert more of the MM and page
cache to folios. For 5.18, multi-page folios should be ready.
The multi-page folios offer some improvement to some workloads. The
80% win is real, but appears to be an artificial benchmark (postgres
startup, which isn't a serious workload). Real workloads (eg building
the kernel, running postgres in a steady state, etc) seem to benefit
between 0-10%. I haven't heard of any performance losses as a result
of this series. Nobody has done any serious performance tuning; I
imagine that tweaking the readahead algorithm could provide some more
interesting wins. There are also other places where we could choose to
create large folios and currently do not, such as writes that are
larger than PAGE_SIZE.
I'd like to thank all my reviewers who've offered review/ack tags:
Christoph Hellwig, David Howells, Jan Kara, Jeff Layton, Johannes
Weiner, Kirill A. Shutemov, Michal Hocko, Mike Rapoport, Vlastimil
Babka, William Kucharski, Yu Zhao and Zi Yan.
I'd also like to thank those who gave feedback I incorporated but
haven't offered up review tags for this part of the series: Nick
Piggin, Mel Gorman, Ming Lei, Darrick Wong, Ted Ts'o, John Hubbard,
Hugh Dickins, and probably a few others who I forget"
* tag 'folio-5.16' of git://git.infradead.org/users/willy/pagecache: (90 commits)
mm/writeback: Add folio_write_one
mm/filemap: Add FGP_STABLE
mm/filemap: Add filemap_get_folio
mm/filemap: Convert mapping_get_entry to return a folio
mm/filemap: Add filemap_add_folio()
mm/filemap: Add filemap_alloc_folio
mm/page_alloc: Add folio allocation functions
mm/lru: Add folio_add_lru()
mm/lru: Convert __pagevec_lru_add_fn to take a folio
mm: Add folio_evictable()
mm/workingset: Convert workingset_refault() to take a folio
mm/filemap: Add readahead_folio()
mm/filemap: Add folio_mkwrite_check_truncate()
mm/filemap: Add i_blocks_per_folio()
mm/writeback: Add folio_redirty_for_writepage()
mm/writeback: Add folio_account_redirty()
mm/writeback: Add folio_clear_dirty_for_io()
mm/writeback: Add folio_cancel_dirty()
mm/writeback: Add folio_account_cleaned()
mm/writeback: Add filemap_dirty_folio()
...
Currently collapse_file does not explicitly check PG_writeback, instead,
page_has_private and try_to_release_page are used to filter writeback
pages. This does not work for xfs with blocksize equal to or larger
than pagesize, because in such case xfs has no page->private.
This makes collapse_file bail out early for writeback page. Otherwise,
xfs end_page_writeback will panic as follows.
page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:ffff0003f88c86a8 index:0x0 pfn:0x84ef32
aops:xfs_address_space_operations [xfs] ino:30000b7 dentry name:"libtest.so"
flags: 0x57fffe0000008027(locked|referenced|uptodate|active|writeback)
raw: 57fffe0000008027 ffff80001b48bc28 ffff80001b48bc28 ffff0003f88c86a8
raw: 0000000000000000 0000000000000000 00000000ffffffff ffff0000c3e9a000
page dumped because: VM_BUG_ON_PAGE(((unsigned int) page_ref_count(page) + 127u <= 127u))
page->mem_cgroup:ffff0000c3e9a000
------------[ cut here ]------------
kernel BUG at include/linux/mm.h:1212!
Internal error: Oops - BUG: 0 [#1] SMP
Modules linked in:
BUG: Bad page state in process khugepaged pfn:84ef32
xfs(E)
page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:0 index:0x0 pfn:0x84ef32
libcrc32c(E) rfkill(E) aes_ce_blk(E) crypto_simd(E) ...
CPU: 25 PID: 0 Comm: swapper/25 Kdump: loaded Tainted: ...
pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--)
Call trace:
end_page_writeback+0x1c0/0x214
iomap_finish_page_writeback+0x13c/0x204
iomap_finish_ioend+0xe8/0x19c
iomap_writepage_end_bio+0x38/0x50
bio_endio+0x168/0x1ec
blk_update_request+0x278/0x3f0
blk_mq_end_request+0x34/0x15c
virtblk_request_done+0x38/0x74 [virtio_blk]
blk_done_softirq+0xc4/0x110
__do_softirq+0x128/0x38c
__irq_exit_rcu+0x118/0x150
irq_exit+0x1c/0x30
__handle_domain_irq+0x8c/0xf0
gic_handle_irq+0x84/0x108
el1_irq+0xcc/0x180
arch_cpu_idle+0x18/0x40
default_idle_call+0x4c/0x1a0
cpuidle_idle_call+0x168/0x1e0
do_idle+0xb4/0x104
cpu_startup_entry+0x30/0x9c
secondary_start_kernel+0x104/0x180
Code: d4210000 b0006161 910c8021 94013f4d (d4210000)
---[ end trace 4a88c6a074082f8c ]---
Kernel panic - not syncing: Oops - BUG: Fatal exception in interrupt
Link: https://lkml.kernel.org/r/20211022023052.33114-1-rongwei.wang@linux.alibaba.com
Fixes: 99cb0dbd47 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Signed-off-by: Xu Yu <xuyu@linux.alibaba.com>
Suggested-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Song Liu <song@kernel.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mike Kravetz <mike.kravetz@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>
Convert all the callers to call page_folio(). Most of them were already
using a head page, but a few of them I can't prove were, so this may
actually fix a bug.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Convert all callers of mem_cgroup_charge() to call page_folio() on the
page they're currently passing in. Many of them will be converted to
use folios themselves soon.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
khugepaged's collapse_file() currently uses SGP_NOHUGE to tell
shmem_getpage() not to try allocating a huge page, in the very unlikely
event that a racing hole-punch removes the swapped or fallocated page as
soon as i_pages lock is dropped.
We want to consolidate shmem's huge decisions, removing SGP_HUGE and
SGP_NOHUGE; but cannot quite persuade ourselves that it's okay to regress
the protection in this case - Yang Shi points out that the huge page would
remain indefinitely, charged to root instead of the intended memcg.
collapse_file() should not even allocate a small page in this case: why
proceed if someone is punching a hole? SGP_READ is almost the right flag
here, except that it optimizes away from a fallocated page, with NULL to
tell caller to fill with zeroes (like a hole); whereas collapse_file()'s
sequence relies on using a cache page. Add SGP_NOALLOC just for this.
There are too many consecutive "if (page"s there in shmem_getpage_gfp():
group it better; and fix the outdated "bring it back from swap" comment.
Link: https://lkml.kernel.org/r/1355343b-acf-4653-ef79-6aee40214ac5@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.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>
Transparent huge pages are supported for read-only non-shmem files, but
are only used for vmas with VM_DENYWRITE. This condition ensures that
file THPs are protected from writes while an application is running
(ETXTBSY). Any existing file THPs are then dropped from the page cache
when a file is opened for write in do_dentry_open(). Since sys_mmap
ignores MAP_DENYWRITE, this constrains the use of file THPs to vmas
produced by execve().
Systems that make heavy use of shared libraries (e.g. Android) are unable
to apply VM_DENYWRITE through the dynamic linker, preventing them from
benefiting from the resultant reduced contention on the TLB.
This patch reduces the constraint on file THPs allowing use with any
executable mapping from a file not opened for write (see
inode_is_open_for_write()). It also introduces additional conditions to
ensure that files opened for write will never be backed by file THPs.
Restricting the use of THPs to executable mappings eliminates the risk
that a read-only file later opened for write would encounter significant
latencies due to page cache truncation.
The ld linker flag '-z max-page-size=(hugepage size)' can be used to
produce executables with the necessary layout. The dynamic linker must
map these file's segments at a hugepage size aligned vma for the mapping
to be backed with THPs.
Comparison of the performance characteristics of 4KB and 2MB-backed
libraries follows; the Android dex2oat tool was used to AOT compile an
example application on a single ARM core.
4KB Pages:
==========
count event_name # count / runtime
598,995,035,942 cpu-cycles # 1.800861 GHz
81,195,620,851 raw-stall-frontend # 244.112 M/sec
347,754,466,597 iTLB-loads # 1.046 G/sec
2,970,248,900 iTLB-load-misses # 0.854122% miss rate
Total test time: 332.854998 seconds.
2MB Pages:
==========
count event_name # count / runtime
592,872,663,047 cpu-cycles # 1.800358 GHz
76,485,624,143 raw-stall-frontend # 232.261 M/sec
350,478,413,710 iTLB-loads # 1.064 G/sec
803,233,322 iTLB-load-misses # 0.229182% miss rate
Total test time: 329.826087 seconds
A check of /proc/$(pidof dex2oat64)/smaps shows THPs in use:
/apex/com.android.art/lib64/libart.so
FilePmdMapped: 4096 kB
/apex/com.android.art/lib64/libart-compiler.so
FilePmdMapped: 2048 kB
Link: https://lkml.kernel.org/r/20210406000930.3455850-1-cfijalkovich@google.com
Signed-off-by: Collin Fijalkovich <cfijalkovich@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Acked-by: Song Liu <song@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Hridya Valsaraju <hridya@google.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Tim Murray <timmurray@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 99cb0dbd47 ("mm,thp: add read-only THP support for
(non-shmem) FS"), read-only THP file mapping is supported. But it forgot
to add checking for it in transparent_hugepage_enabled(). To fix it, we
add checking for read-only THP file mapping and also introduce helper
transhuge_vma_enabled() to check whether thp is enabled for specified vma
to reduce duplicated code. We rename transparent_hugepage_enabled to
transparent_hugepage_active to make the code easier to follow as suggested
by David Hildenbrand.
[linmiaohe@huawei.com: define transhuge_vma_enabled next to transhuge_vma_suitable]
Link: https://lkml.kernel.org/r/20210514093007.4117906-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210511134857.1581273-4-linmiaohe@huawei.com
Fixes: 99cb0dbd47 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
RECLAIM_ZONE was assumed to be unused because it was never explicitly
used in the kernel. However, there were a number of places where it was
checked implicitly by checking 'node_reclaim_mode' for a zero value.
These zero checks are not great because it is not obvious what a zero
mode *means* in the code. Replace them with a helper which makes it
more obvious: node_reclaim_enabled().
This helper also provides a handy place to explicitly check the
RECLAIM_ZONE bit itself. Check it explicitly there to make it more
obvious where the bit can affect behavior.
This should have no functional impact.
Link: https://lkml.kernel.org/r/20210219172559.BF589C44@viggo.jf.intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: "Tobin C. Harding" <tobin@kernel.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We know it must meet the !is_swap_pte() and !pte_none() condition if we
reach here. Since !is_swap_pte() indicates pte_none() or pte_present()
is met, it's guaranteed that pte must be present here.
Link: https://lkml.kernel.org/r/20210325135647.64106-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The out label here is unneeded because it just goes to out_up_write label.
Remove it to make code more concise.
Link: https://lkml.kernel.org/r/20210325135647.64106-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Cleanup for khugepaged".
This series contains cleanups to remove unnecessary out label and
meaningless !pte_present() check. Also use helper function to simplify
the code. More details can be found in the respective changelogs.
This patch (of 3):
We could use helper function range_in_vma() to check whether the desired
range is inside the vma to simplify the code.
Link: https://lkml.kernel.org/r/20210325135647.64106-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210325135647.64106-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
READ_ONCE() is more selective and lightweight. It is more appropriate
that using a READ_ONCE() for the certain variable to prevent the
compiler from reordering.
Link: https://lkml.kernel.org/r/20210323092730.247583-1-yanfei.xu@windriver.com
Signed-off-by: Yanfei Xu <yanfei.xu@windriver.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In writable and !referenced case, the result value should be
SCAN_LACK_REFERENCED_PAGE for trace_mm_collapse_huge_page_isolate()
instead of default 0 (SCAN_FAIL) here.
Link: https://lkml.kernel.org/r/20210306032947.35921-5-linmiaohe@huawei.com
Fixes: 7d2eba0557 ("mm: add tracepoint for scanning pages")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 4d45e75a99 ("mm: remove the now-unnecessary mmget_still_valid()
hack") have made khugepaged_test_exit() suitable for check mm->mm_users
against 0. Use this helper here.
Link: https://lkml.kernel.org/r/20210306032947.35921-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
smp_wmb() is needed to avoid the copy_huge_page writes to become visible
after the set_pmd_at() write here. But we can reuse the smp_wmb() inside
__SetPageUptodate() to remove this redundant one.
Link: https://lkml.kernel.org/r/20210306032947.35921-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Cleanup and fixup for khugepaged", v2.
This series contains cleanups to remove unneeded return value, use
helper function and so on. And there is one fix to correct the wrong
result value for trace_mm_collapse_huge_page_isolate().
This patch (of 4):
The return value of khugepaged_collapse_pte_mapped_thps() is never checked
since it's introduced. We should remove such unneeded return value.
Link: https://lkml.kernel.org/r/20210306032947.35921-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210306032947.35921-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently if thp enabled=[madvise], mounting a tmpfs filesystem with
huge=always and mmapping files from that tmpfs does not result in
khugepaged collapsing those mappings, despite the mount flag indicating
that it should.
Fix that by breaking up the blocks of tests in hugepage_vma_check a little
bit, and testing things in the correct order.
Link: https://lkml.kernel.org/r/20201124194925.623931-4-riel@surriel.com
Fixes: c2231020ea ("mm: thp: register mm for khugepaged when merging vma for shmem")
Signed-off-by: Rik van Riel <riel@surriel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xu Yu <xuyu@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we use struct per_cpu_nodestat to cache the vmstat counters,
which leads to inaccurate statistics especially THP vmstat counters. In
the systems with hundreds of processors it can be GBs of memory. For
example, for a 96 CPUs system, the threshold is the maximum number of 125.
And the per cpu counters can cache 23.4375 GB in total.
The THP page is already a form of batched addition (it will add 512 worth
of memory in one go) so skipping the batching seems like sensible.
Although every THP stats update overflows the per-cpu counter, resorting
to atomic global updates. But it can make the statistics more accuracy
for the THP vmstat counters.
So we convert the NR_SHMEM_THPS account to pages. This patch is
consistent with 8f182270df ("mm/swap.c: flush lru pvecs on compound page
arrival"). Doing this also can make the unit of vmstat counters more
unified. Finally, the unit of the vmstat counters are pages, kB and
bytes. The B/KB suffix can tell us that the unit is bytes or kB. The
rest which is without suffix are pages.
Link: https://lkml.kernel.org/r/20201228164110.2838-5-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Cc: Rafael. J. Wysocki <rafael@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
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>
Currently we use struct per_cpu_nodestat to cache the vmstat counters,
which leads to inaccurate statistics especially THP vmstat counters. In
the systems with if hundreds of processors it can be GBs of memory. For
example, for a 96 CPUs system, the threshold is the maximum number of 125.
And the per cpu counters can cache 23.4375 GB in total.
The THP page is already a form of batched addition (it will add 512 worth
of memory in one go) so skipping the batching seems like sensible.
Although every THP stats update overflows the per-cpu counter, resorting
to atomic global updates. But it can make the statistics more accuracy
for the THP vmstat counters.
So we convert the NR_FILE_THPS account to pages. This patch is consistent
with 8f182270df ("mm/swap.c: flush lru pvecs on compound page arrival").
Doing this also can make the unit of vmstat counters more unified.
Finally, the unit of the vmstat counters are pages, kB and bytes. The
B/KB suffix can tell us that the unit is bytes or kB. The rest which is
without suffix are pages.
Link: https://lkml.kernel.org/r/20201228164110.2838-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Cc: Rafael. J. Wysocki <rafael@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
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>
In preparation for const-ifying the anonymous struct field of
'struct vm_fault', rework __collapse_huge_page_swapin() to avoid
continuously updating vmf.address and instead populate a new
'struct vm_fault' on the stack for each page being processed.
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Will Deacon <will@kernel.org>
Range checks can folded into proper conversion function. kstrto*() exist
for all arithmetic types.
Link: https://lkml.kernel.org/r/20201122123759.GC92364@localhost.localdomain
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: Convert sysfs sprintf family to sysfs_emit", v2.
Use the new sysfs_emit family and not the sprintf family.
This patch (of 5):
Use the sysfs_emit function instead of the sprintf family.
Done with cocci script as in commit 3c6bff3cf9 ("RDMA: Convert sysfs
kobject * show functions to use sysfs_emit()")
Link: https://lkml.kernel.org/r/cover.1605376435.git.joe@perches.com
Link: https://lkml.kernel.org/r/9c249215bad6df616ba0410ad980042694970c1b.1605376435.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Hugh Dickins <hughd@google.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: Matthew Wilcox <willy@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add missed parameter explanation for some kernel-doc warnings:
mm/khugepaged.c:102: warning: Function parameter or member 'nr_pte_mapped_thp' not described in 'mm_slot'
mm/khugepaged.c:102: warning: Function parameter or member 'pte_mapped_thp' not described in 'mm_slot'
mm/khugepaged.c:1424: warning: Function parameter or member 'mm' not described in 'collapse_pte_mapped_thp'
mm/khugepaged.c:1424: warning: Function parameter or member 'addr' not described in 'collapse_pte_mapped_thp'
mm/khugepaged.c:1626: warning: Function parameter or member 'mm' not described in 'collapse_file'
mm/khugepaged.c:1626: warning: Function parameter or member 'file' not described in 'collapse_file'
mm/khugepaged.c:1626: warning: Function parameter or member 'start' not described in 'collapse_file'
mm/khugepaged.c:1626: warning: Function parameter or member 'hpage' not described in 'collapse_file'
mm/khugepaged.c:1626: warning: Function parameter or member 'node' not described in 'collapse_file'
Link: https://lkml.kernel.org/r/1605597325-25284-1-git-send-email-alex.shi@linux.alibaba.com
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As huge page usage in the page cache and for shmem files proliferates in
our production environment, the performance monitoring team has asked for
per-cgroup stats on those pages.
We already track and export anon_thp per cgroup. We already track file
THP and shmem THP per node, so making them per-cgroup is only a matter of
switching from node to lruvec counters. All callsites are in places where
the pages are charged and locked, so page->memcg is stable.
[hannes@cmpxchg.org: add documentation]
Link: https://lkml.kernel.org/r/20201026174029.GC548555@cmpxchg.org
Link: https://lkml.kernel.org/r/20201022151844.489337-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The preceding patches have ensured that core dumping properly takes the
mmap_lock. Thanks to that, we can now remove mmget_still_valid() and all
its users.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200827114932.3572699-8-jannh@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When memory is hotplug added or removed the min_free_kbytes should be
recalculated based on what is expected by khugepaged. Currently after
hotplug, min_free_kbytes will be set to a lower default and higher
default set when THP enabled is lost.
This change restores min_free_kbytes as expected for THP consumers.
[vijayb@linux.microsoft.com: v5]
Link: https://lkml.kernel.org/r/1601398153-5517-1-git-send-email-vijayb@linux.microsoft.com
Fixes: f000565adb ("thp: set recommended min free kbytes")
Signed-off-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Allen Pais <apais@microsoft.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/1600305709-2319-2-git-send-email-vijayb@linux.microsoft.com
Link: https://lkml.kernel.org/r/1600204258-13683-1-git-send-email-vijayb@linux.microsoft.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There have been elusive reports of filemap_fault() hitting its
VM_BUG_ON_PAGE(page_to_pgoff(page) != offset, page) on kernels built
with CONFIG_READ_ONLY_THP_FOR_FS=y.
Suren has hit it on a kernel with CONFIG_READ_ONLY_THP_FOR_FS=y and
CONFIG_NUMA is not set: and he has analyzed it down to how khugepaged
without NUMA reuses the same huge page after collapse_file() failed
(whereas NUMA targets its allocation to the respective node each time).
And most of us were usually testing with CONFIG_NUMA=y kernels.
collapse_file(old start)
new_page = khugepaged_alloc_page(hpage)
__SetPageLocked(new_page)
new_page->index = start // hpage->index=old offset
new_page->mapping = mapping
xas_store(&xas, new_page)
filemap_fault
page = find_get_page(mapping, offset)
// if offset falls inside hpage then
// compound_head(page) == hpage
lock_page_maybe_drop_mmap()
__lock_page(page)
// collapse fails
xas_store(&xas, old page)
new_page->mapping = NULL
unlock_page(new_page)
collapse_file(new start)
new_page = khugepaged_alloc_page(hpage)
__SetPageLocked(new_page)
new_page->index = start // hpage->index=new offset
new_page->mapping = mapping // mapping becomes valid again
// since compound_head(page) == hpage
// page_to_pgoff(page) got changed
VM_BUG_ON_PAGE(page_to_pgoff(page) != offset)
An initial patch replaced __SetPageLocked() by lock_page(), which did
fix the race which Suren illustrates above. But testing showed that it's
not good enough: if the racing task's __lock_page() gets delayed long
after its find_get_page(), then it may follow collapse_file(new start)'s
successful final unlock_page(), and crash on the same VM_BUG_ON_PAGE.
It could be fixed by relaxing filemap_fault()'s VM_BUG_ON_PAGE to a
check and retry (as is done for mapping), with similar relaxations in
find_lock_entry() and pagecache_get_page(): but it's not obvious what
else might get caught out; and khugepaged non-NUMA appears to be unique
in exposing a page to page cache, then revoking, without going through
a full cycle of freeing before reuse.
Instead, non-NUMA khugepaged_prealloc_page() release the old page
if anyone else has a reference to it (1% of cases when I tested).
Although never reported on huge tmpfs, I believe its find_lock_entry()
has been at similar risk; but huge tmpfs does not rely on khugepaged
for its normal working nearly so much as READ_ONLY_THP_FOR_FS does.
Reported-by: Denis Lisov <dennis.lissov@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206569
Link: https://lore.kernel.org/linux-mm/?q=20200219144635.3b7417145de19b65f258c943%40linux-foundation.org
Reported-by: Qian Cai <cai@lca.pw>
Link: https://lore.kernel.org/linux-xfs/?q=20200616013309.GB815%40lca.pw
Reported-and-analyzed-by: Suren Baghdasaryan <surenb@google.com>
Fixes: 87c460a0bd ("mm/khugepaged: collapse_shmem() without freezing new_page")
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@vger.kernel.org # v4.9+
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
collapse_file() in khugepaged passes PAGE_SIZE as the number of pages to
be read to page_cache_sync_readahead(). The intent was probably to read
a single page. Fix it to use the number of pages to the end of the
window instead.
Fixes: 99cb0dbd47 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Eric Biggers <ebiggers@google.com>
Link: https://lkml.kernel.org/r/20200903140844.14194-2-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
syzbot crashes on the VM_BUG_ON_MM(khugepaged_test_exit(mm), mm) in
__khugepaged_enter(): yes, when one thread is about to dump core, has set
core_state, and is waiting for others, another might do something calling
__khugepaged_enter(), which now crashes because I lumped the core_state
test (known as "mmget_still_valid") into khugepaged_test_exit(). I still
think it's best to lump them together, so just in this exceptional case,
check mm->mm_users directly instead of khugepaged_test_exit().
Fixes: bbe98f9cad ("khugepaged: khugepaged_test_exit() check mmget_still_valid()")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008141503370.18085@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In current implementation, newly created or swap-in anonymous page is
started on active list. Growing active list results in rebalancing
active/inactive list so old pages on active list are demoted to inactive
list. Hence, the page on active list isn't protected at all.
Following is an example of this situation.
Assume that 50 hot pages on active list. Numbers denote the number of
pages on active/inactive list (active | inactive).
1. 50 hot pages on active list
50(h) | 0
2. workload: 50 newly created (used-once) pages
50(uo) | 50(h)
3. workload: another 50 newly created (used-once) pages
50(uo) | 50(uo), swap-out 50(h)
This patch tries to fix this issue. Like as file LRU, newly created or
swap-in anonymous pages will be inserted to the inactive list. They are
promoted to active list if enough reference happens. This simple
modification changes the above example as following.
1. 50 hot pages on active list
50(h) | 0
2. workload: 50 newly created (used-once) pages
50(h) | 50(uo)
3. workload: another 50 newly created (used-once) pages
50(h) | 50(uo), swap-out 50(uo)
As you can see, hot pages on active list would be protected.
Note that, this implementation has a drawback that the page cannot be
promoted and will be swapped-out if re-access interval is greater than the
size of inactive list but less than the size of total(active+inactive).
To solve this potential issue, following patch will apply workingset
detection similar to the one that's already applied to file LRU.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Link: http://lkml.kernel.org/r/1595490560-15117-3-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move collapse_huge_page()'s mmget_still_valid() check into
khugepaged_test_exit() itself. collapse_huge_page() is used for anon THP
only, and earned its mmget_still_valid() check because it inserts a huge
pmd entry in place of the page table's pmd entry; whereas
collapse_file()'s retract_page_tables() or collapse_pte_mapped_thp()
merely clears the page table's pmd entry. But core dumping without mmap
lock must have been as open to mistaking a racily cleared pmd entry for a
page table at physical page 0, as exit_mmap() was. And we certainly have
no interest in mapping as a THP once dumping core.
Fixes: 59ea6d06cf ("coredump: fix race condition between collapse_huge_page() and core dumping")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021217020.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Only once have I seen this scenario (and forgot even to notice what forced
the eventual crash): a sequence of "BUG: Bad page map" alerts from
vm_normal_page(), from zap_pte_range() servicing exit_mmap();
pmd:00000000, pte values corresponding to data in physical page 0.
The pte mappings being zapped in this case were supposed to be from a huge
page of ext4 text (but could as well have been shmem): my belief is that
it was racing with collapse_file()'s retract_page_tables(), found *pmd
pointing to a page table, locked it, but *pmd had become 0 by the time
start_pte was decided.
In most cases, that possibility is excluded by holding mmap lock; but
exit_mmap() proceeds without mmap lock. Most of what's run by khugepaged
checks khugepaged_test_exit() after acquiring mmap lock:
khugepaged_collapse_pte_mapped_thps() and hugepage_vma_revalidate() do so,
for example. But retract_page_tables() did not: fix that.
The fix is for retract_page_tables() to check khugepaged_test_exit(),
after acquiring mmap lock, before doing anything to the page table.
Getting the mmap lock serializes with __mmput(), which briefly takes and
drops it in __khugepaged_exit(); then the khugepaged_test_exit() check on
mm_users makes sure we don't touch the page table once exit_mmap() might
reach it, since exit_mmap() will be proceeding without mmap lock, not
expecting anyone to be racing with it.
Fixes: f3f0e1d215 ("khugepaged: add support of collapse for tmpfs/shmem pages")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021215400.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When retract_page_tables() removes a page table to make way for a huge
pmd, it holds huge page lock, i_mmap_lock_write, mmap_write_trylock and
pmd lock; but when collapse_pte_mapped_thp() does the same (to handle the
case when the original mmap_write_trylock had failed), only
mmap_write_trylock and pmd lock are held.
That's not enough. One machine has twice crashed under load, with "BUG:
spinlock bad magic" and GPF on 6b6b6b6b6b6b6b6b. Examining the second
crash, page_vma_mapped_walk_done()'s spin_unlock of pvmw->ptl (serving
page_referenced() on a file THP, that had found a page table at *pmd)
discovers that the page table page and its lock have already been freed by
the time it comes to unlock.
Follow the example of retract_page_tables(), but we only need one of huge
page lock or i_mmap_lock_write to secure against this: because it's the
narrower lock, and because it simplifies collapse_pte_mapped_thp() to know
the hpage earlier, choose to rely on huge page lock here.
Fixes: 27e1f82731 ("khugepaged: enable collapse pmd for pte-mapped THP")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org> [5.4+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021213070.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pmdp_collapse_flush() should be given the start address at which the huge
page is mapped, haddr: it was given addr, which at that point has been
used as a local variable, incremented to the end address of the extent.
Found by source inspection while chasing a hugepage locking bug, which I
then could not explain by this. At first I thought this was very bad;
then saw that all of the page translations that were not flushed would
actually still point to the right pages afterwards, so harmless; then
realized that I know nothing of how different architectures and models
cache intermediate paging structures, so maybe it matters after all -
particularly since the page table concerned is immediately freed.
Much easier to fix than to think about.
Fixes: 27e1f82731 ("khugepaged: enable collapse pmd for pte-mapped THP")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org> [5.4+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021204390.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
khugepaged has to drop mmap lock several times while collapsing a page.
The situation can change while the lock is dropped and we need to
re-validate that the VMA is still in place and the PMD is still subject
for collapse.
But we miss one corner case: while collapsing an anonymous pages the VMA
could be replaced with file VMA. If the file VMA doesn't have any
private pages we get NULL pointer dereference:
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
anon_vma_lock_write include/linux/rmap.h:120 [inline]
collapse_huge_page mm/khugepaged.c:1110 [inline]
khugepaged_scan_pmd mm/khugepaged.c:1349 [inline]
khugepaged_scan_mm_slot mm/khugepaged.c:2110 [inline]
khugepaged_do_scan mm/khugepaged.c:2193 [inline]
khugepaged+0x3bba/0x5a10 mm/khugepaged.c:2238
The fix is to make sure that the VMA is anonymous in
hugepage_vma_revalidate(). The helper is only used for collapsing
anonymous pages.
Fixes: 99cb0dbd47 ("mm,thp: add read-only THP support for (non-shmem) FS")
Reported-by: syzbot+ed318e8b790ca72c5ad0@syzkaller.appspotmail.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200722121439.44328-1-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
They're the same function, and for the purpose of all callers they are
equivalent to lru_cache_add().
[akpm@linux-foundation.org: fix it for local_lock changes]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-5-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Swapin faults were the last event to charge pages after they had already
been put on the LRU list. Now that we charge directly on swapin, the
lrucare portion of the charge code is unused.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-19-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With the page->mapping requirement gone from memcg, we can charge anon and
file-thp pages in one single step, right after they're allocated.
This removes two out of three API calls - especially the tricky commit
step that needed to happen at just the right time between when the page is
"set up" and when it's "published" - somewhat vague and fluid concepts
that varied by page type. All we need is a freshly allocated page and a
memcg context to charge.
v2: prevent double charges on pre-allocated hugepages in khugepaged
[hannes@cmpxchg.org: Fix crash - *hpage could be ERR_PTR instead of NULL]
Link: http://lkml.kernel.org/r/20200512215813.GA487759@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Link: http://lkml.kernel.org/r/20200508183105.225460-13-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memcg maintains a private MEMCG_RSS counter. This divergence from the
generic VM accounting means unnecessary code overhead, and creates a
dependency for memcg that page->mapping is set up at the time of charging,
so that page types can be told apart.
Convert the generic accounting sites to mod_lruvec_page_state and friends
to maintain the per-cgroup vmstat counter of NR_ANON_MAPPED. We use
lock_page_memcg() to stabilize page->mem_cgroup during rmap changes, the
same way we do for NR_FILE_MAPPED.
With the previous patch removing MEMCG_CACHE and the private NR_SHMEM
counter, this patch finally eliminates the need to have page->mapping set
up at charge time. However, we need to have page->mem_cgroup set up by
the time rmap runs and does the accounting, so switch the commit and the
rmap callbacks around.
v2: fix temporary accounting bug by switching rmap<->commit (Joonsoo)
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-11-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memcg maintains private MEMCG_CACHE and NR_SHMEM counters. This
divergence from the generic VM accounting means unnecessary code overhead,
and creates a dependency for memcg that page->mapping is set up at the
time of charging, so that page types can be told apart.
Convert the generic accounting sites to mod_lruvec_page_state and friends
to maintain the per-cgroup vmstat counters of NR_FILE_PAGES and NR_SHMEM.
The page is already locked in these places, so page->mem_cgroup is stable;
we only need minimal tweaks of two mem_cgroup_migrate() calls to ensure
it's set up in time.
Then replace MEMCG_CACHE with NR_FILE_PAGES and delete the private
NR_SHMEM accounting sites.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-10-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memcg charging API carries a boolean @compound parameter that tells
whether the page we're dealing with is a hugepage.
mem_cgroup_commit_charge() has another boolean @lrucare that indicates
whether the page needs LRU locking or not while charging. The majority of
callsites know those parameters at compile time, which results in a lot of
naked "false, false" argument lists. This makes for cryptic code and is a
breeding ground for subtle mistakes.
Thankfully, the huge page state can be inferred from the page itself and
doesn't need to be passed along. This is safe because charging completes
before the page is published and somebody may split it.
Simplify the callsites by removing @compound, and let memcg infer the
state by using hpage_nr_pages() unconditionally. That function does
PageTransHuge() to identify huge pages, which also helpfully asserts that
nobody passes in tail pages by accident.
The following patches will introduce a new charging API, best not to carry
over unnecessary weight.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-4-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
'max_ptes_shared' specifies how many pages can be shared across multiple
processes. Exceeding the number would block the collapse::
/sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_shared
A higher value may increase memory footprint for some workloads.
By default, at least half of pages has to be not shared.
[colin.king@canonical.com: fix several spelling mistakes]
Link: http://lkml.kernel.org/r/20200420084241.65433-1-colin.king@canonical.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: http://lkml.kernel.org/r/20200416160026.16538-9-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We can collapse PTE-mapped compound pages. We only need to avoid handling
them more than once: lock/unlock page only once if it's present in the PMD
range multiple times as it handled on compound level. The same goes for
LRU isolation and putback.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: http://lkml.kernel.org/r/20200416160026.16538-7-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The page can be included into collapse as long as it doesn't have extra
pins (from GUP or otherwise).
Logic to check the refcount is moved to a separate function. For pages in
swap cache, add compound_nr(page) to the expected refcount, in order to
handle the compound page case. This is in preparation for the following
patch.
VM_BUG_ON_PAGE() was removed from __collapse_huge_page_copy() as the
invariant it checks is no longer valid: the source can be mapped multiple
times now.
[yang.shi@linux.alibaba.com: remove error message when checking external pins]
Link: http://lkml.kernel.org/r/1589317383-9595-1-git-send-email-yang.shi@linux.alibaba.com
[cai@lca.pw: fix set-but-not-used warning]
Link: http://lkml.kernel.org/r/20200521145644.GA6367@ovpn-112-192.phx2.redhat.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: http://lkml.kernel.org/r/20200416160026.16538-6-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
collapse_huge_page() tries to swap in pages that are part of the PMD
range. Just swapped in page goes though LRU add cache. The cache gets
extra reference on the page.
The extra reference can lead to the collapse fail: the following
__collapse_huge_page_isolate() would check refcount and abort collapse
seeing unexpected refcount.
The fix is to drain local LRU add cache in
__collapse_huge_page_swapin() if we successfully swapped in any pages.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: http://lkml.kernel.org/r/20200416160026.16538-5-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Having a page in LRU add cache offsets page refcount and gives
false-negative on PageLRU(). It reduces collapse success rate.
Drain all LRU add caches before scanning. It happens relatively rare and
should not disturb the system too much.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: http://lkml.kernel.org/r/20200416160026.16538-4-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__collapse_huge_page_swapin() checks the number of referenced PTE to
decide if the memory range is hot enough to justify swapin.
We have few problems with the approach:
- It is way too late: we can do the check much earlier and safe time.
khugepaged_scan_pmd() already knows if we have any pages to swap in
and number of referenced page.
- It stops collapse altogether if there's not enough referenced pages,
not only swappingin.
Fix it by making the right check early. We also can avoid additional
page table scanning if khugepaged_scan_pmd() haven't found any swap
entries.
Fixes: 0db501f7a3 ("mm, thp: convert from optimistic swapin collapsing to conservative")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: http://lkml.kernel.org/r/20200416160026.16538-3-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When collapse_file() calls try_to_release_page(), it has already isolated
the page: so if releasing buffers happens to fail (as it sometimes does),
remember to putback_lru_page(): otherwise that page is left unreclaimable
and unfreeable, and the file extent uncollapsible.
Fixes: 99cb0dbd47 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: <stable@vger.kernel.org> [5.4+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2005231837500.1766@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Don't collapse the huge PMD if there is any userfault write protected
small PTEs. The problem is that the write protection is in small page
granularity and there's no way to keep all these write protection
information if the small pages are going to be merged into a huge PMD.
The same thing needs to be considered for swap entries and migration
entries. So do the check as well disregarding khugepaged_max_ptes_swap.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Link: http://lkml.kernel.org/r/20200220163112.11409-12-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some comments for MADV_FREE is revised and added to help people understand
the MADV_FREE code, especially the page flag, PG_swapbacked. This makes
page_is_file_cache() isn't consistent with its comments. So the function
is renamed to page_is_file_lru() to make them consistent again. All these
are put in one patch as one logical change.
Suggested-by: David Hildenbrand <david@redhat.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@kernel.org>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200317100342.2730705-1-ying.huang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit e496cf3d78 ("thp: introduce CONFIG_TRANSPARENT_HUGE_PAGECACHE")
notes that it should be reverted when the PowerPC problem was fixed. The
commit fixing the PowerPC problem (953c66c2b2) did not revert the
commit; instead setting CONFIG_TRANSPARENT_HUGE_PAGECACHE to the same as
CONFIG_TRANSPARENT_HUGEPAGE. Checking with Kirill and Aneesh, this was an
oversight, so remove the Kconfig symbol and undo the work of commit
e496cf3d78.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: http://lkml.kernel.org/r/20200318140253.6141-6-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the declaration and definition for is_vma_temporary_stack() are
scattered. Lets make is_vma_temporary_stack() helper available for
general use and also drop the declaration from (include/linux/huge_mm.h)
which is no longer required. While at this, rename this as
vma_is_temporary_stack() in line with existing helpers. This should not
cause any functional change.
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1582782965-3274-4-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/vma: some more minor changes", v2.
The motivation here is to consolidate VMA flags and helpers in generic
memory header and reduce code duplication when ever applicable. If there
are other possible similar instances which might be missing here, please
do let me me know. I will be happy to incorporate them.
This patch (of 3):
Move VM_NO_KHUGEPAGED into generic header (include/linux/mm.h). This just
makes sure that no VMA flag is scattered in individual function files any
longer. While at this, fix an old comment which is no longer valid. This
should not cause any functional change.
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1582782965-3274-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For non-shmem file THPs, khugepaged only collapses read only .text
mapping (VM_DENYWRITE). These pages should not be dirty except the case
where the file hasn't been flushed since first write.
Call filemap_flush() in collapse_file() to accelerate the write back in
such cases.
Link: http://lkml.kernel.org/r/20191106060930.2571389-3-songliubraving@fb.com
Signed-off-by: Song Liu <songliubraving@fb.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In collapse_file(), for !is_shmem case, current check cannot guarantee
the locked page is up-to-date. Specifically, xas_unlock_irq() should
not be called before lock_page() and get_page(); and it is necessary to
recheck PageUptodate() after locking the page.
With this bug and CONFIG_READ_ONLY_THP_FOR_FS=y, madvise(HUGE)'ed .text
may contain corrupted data. This is because khugepaged mistakenly
collapses some not up-to-date sub pages into a huge page, and assumes
the huge page is up-to-date. This will NOT corrupt data in the disk,
because the page is read-only and never written back. Fix this by
properly checking PageUptodate() after locking the page. This check
replaces "VM_BUG_ON_PAGE(!PageUptodate(page), page);".
Also, move PageDirty() check after locking the page. Current khugepaged
should not try to collapse dirty file THP, because it is limited to
read-only .text. The only case we hit a dirty page here is when the
page hasn't been written since write. Bail out and retry when this
happens.
syzbot reported bug on previous version of this patch.
Link: http://lkml.kernel.org/r/20191106060930.2571389-2-songliubraving@fb.com
Fixes: 99cb0dbd47 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: Song Liu <songliubraving@fb.com>
Reported-by: syzbot+efb9e48b9fbdc49bb34a@syzkaller.appspotmail.com
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
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>
I got some khugepaged spew on a 32bit x86:
BUG: sleeping function called from invalid context at include/linux/mmu_notifier.h:346
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 25, name: khugepaged
INFO: lockdep is turned off.
CPU: 1 PID: 25 Comm: khugepaged Not tainted 5.4.0-rc5-elk+ #206
Hardware name: System manufacturer P5Q-EM/P5Q-EM, BIOS 2203 07/08/2009
Call Trace:
dump_stack+0x66/0x8e
___might_sleep.cold.96+0x95/0xa6
__might_sleep+0x2e/0x80
collapse_huge_page.isra.51+0x5ac/0x1360
khugepaged+0x9a9/0x20f0
kthread+0xf5/0x110
ret_from_fork+0x2e/0x38
Looks like it's due to CONFIG_HIGHPTE=y pte_offset_map()->kmap_atomic()
vs. mmu_notifier_invalidate_range_start(). Let's do the naive approach
and just reorder the two operations.
Link: http://lkml.kernel.org/r/20191029201513.GG1208@intel.com
Fixes: 810e24e009 ("mm/mmu_notifiers: annotate with might_sleep()")
Signed-off-by: Ville Syrjl <ville.syrjala@linux.intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
khugepaged needs exclusive mmap_sem to access page table. When it fails
to lock mmap_sem, the page will fault in as pte-mapped THP. As the page
is already a THP, khugepaged will not handle this pmd again.
This patch enables the khugepaged to retry collapse the page table.
struct mm_slot (in khugepaged.c) is extended with an array, containing
addresses of pte-mapped THPs. We use array here for simplicity. We can
easily replace it with more advanced data structures when needed.
In khugepaged_scan_mm_slot(), if the mm contains pte-mapped THP, we try to
collapse the page table.
Since collapse may happen at an later time, some pages may already fault
in. collapse_pte_mapped_thp() is added to properly handle these pages.
collapse_pte_mapped_thp() also double checks whether all ptes in this pmd
are mapping to the same THP. This is necessary because some subpage of
the THP may be replaced, for example by uprobe. In such cases, it is not
possible to collapse the pmd.
[kirill.shutemov@linux.intel.com: add comments for retract_page_tables()]
Link: http://lkml.kernel.org/r/20190816145443.6ard3iilytc6jlgv@box
Link: http://lkml.kernel.org/r/20190815164525.1848545-6-songliubraving@fb.com
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In previous patch, an application could put part of its text section in
THP via madvise(). These THPs will be protected from writes when the
application is still running (TXTBSY). However, after the application
exits, the file is available for writes.
This patch avoids writes to file THP by dropping page cache for the file
when the file is open for write. A new counter nr_thps is added to struct
address_space. In do_dentry_open(), if the file is open for write and
nr_thps is non-zero, we drop page cache for the whole file.
Link: http://lkml.kernel.org/r/20190801184244.3169074-8-songliubraving@fb.com
Signed-off-by: Song Liu <songliubraving@fb.com>
Reported-by: kbuild test robot <lkp@intel.com>
Acked-by: Rik van Riel <riel@surriel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is (hopefully) the first step to enable THP for non-shmem
filesystems.
This patch enables an application to put part of its text sections to THP
via madvise, for example:
madvise((void *)0x600000, 0x200000, MADV_HUGEPAGE);
We tried to reuse the logic for THP on tmpfs.
Currently, write is not supported for non-shmem THP. khugepaged will only
process vma with VM_DENYWRITE. sys_mmap() ignores VM_DENYWRITE requests
(see ksys_mmap_pgoff). The only way to create vma with VM_DENYWRITE is
execve(). This requirement limits non-shmem THP to text sections.
The next patch will handle writes, which would only happen when the all
the vmas with VM_DENYWRITE are unmapped.
An EXPERIMENTAL config, READ_ONLY_THP_FOR_FS, is added to gate this
feature.
[songliubraving@fb.com: fix build without CONFIG_SHMEM]
Link: http://lkml.kernel.org/r/F53407FB-96CC-42E8-9862-105C92CC2B98@fb.com
[songliubraving@fb.com: fix double unlock in collapse_file()]
Link: http://lkml.kernel.org/r/B960CBFA-8EFC-4DA4-ABC5-1977FFF2CA57@fb.com
Link: http://lkml.kernel.org/r/20190801184244.3169074-7-songliubraving@fb.com
Signed-off-by: Song Liu <songliubraving@fb.com>
Acked-by: Rik van Riel <riel@surriel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
