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| author |   Marek Szyprowski <m.szyprowski@samsung.com> | 2021-10-18 15:16:19 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2021-10-18 20:22:03 -1000 |
| commit | 1ca7554d05ac038c98271f8968ed821266ecaa9c (patch) | |
| tree | 1fcbb98fd7ebc9515e5860cb8052d692dde77555 /mm | |
| parent | mm/secretmem: fix NULL page->mapping dereference in page_is_secretmem() (diff) | |
| download | linux-dev-1ca7554d05ac038c98271f8968ed821266ecaa9c.tar.xz linux-dev-1ca7554d05ac038c98271f8968ed821266ecaa9c.zip | |
mm/thp: decrease nr_thps in file's mapping on THP split
Decrease nr_thps counter in file's mapping to ensure that the page cache
won't be dropped excessively on file write access if page has been
already split.
I've tried a test scenario running a big binary, kernel remaps it with
THPs, then force a THP split with /sys/kernel/debug/split_huge_pages.
During any further open of that binary with O_RDWR or O_WRITEONLY kernel
drops page cache for it, because of non-zero thps counter.
Link: https://lkml.kernel.org/r/20211012120237.2600-1-m.szyprowski@samsung.com
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: 09d91cda0e82 ("mm,thp: avoid writes to file with THP in pagecache")
Fixes: 06d3eff62d9d ("mm/thp: fix node page state in split_huge_page_to_list()")
Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: <sfoon.kim@samsung.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: 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>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/huge_memory.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 5e9ef0fc261e..92192cb086c7 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2700,12 +2700,14 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) if (mapping) { int nr = thp_nr_pages(head); - if (PageSwapBacked(head)) + if (PageSwapBacked(head)) { __mod_lruvec_page_state(head, NR_SHMEM_THPS, -nr); - else + } else { __mod_lruvec_page_state(head, NR_FILE_THPS, -nr); + filemap_nr_thps_dec(mapping); + } } __split_huge_page(page, list, end); |