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authorMarek Szyprowski <m.szyprowski@samsung.com>2021-10-19 01:16:19 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-10-19 09:22:03 +0300
commit1ca7554d05ac038c98271f8968ed821266ecaa9c (patch)
tree1fcbb98fd7ebc9515e5860cb8052d692dde77555 /mm/huge_memory.c
parent79f9bc5843142b649575f887dccdf1c07ad75c20 (diff)
downloadlinux-1ca7554d05ac038c98271f8968ed821266ecaa9c.tar.xz
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/huge_memory.c')
-rw-r--r--mm/huge_memory.c6
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);