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authorKirill A. Shutemov <kirill@shutemov.name>2019-11-30 17:57:15 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-12-01 12:59:09 -0800
commitf1fe80d4ae3396cf3665bd6dc77f4004c1c2e9f8 (patch)
tree0c016f5ea0da2e28754532129a7b417b4df2a36f
parent74d4a5797b89048a5b20746da7e80af1e73b8547 (diff)
mm, thp: do not queue fully unmapped pages for deferred split
Adding fully unmapped pages into deferred split queue is not productive: these pages are about to be freed or they are pinned and cannot be split anyway. Link: http://lkml.kernel.org/r/20190913091849.11151-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/rmap.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 72a3280b982e..b3e381919835 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1292,12 +1292,20 @@ static void page_remove_anon_compound_rmap(struct page *page)
if (TestClearPageDoubleMap(page)) {
/*
* Subpages can be mapped with PTEs too. Check how many of
- * themi are still mapped.
+ * them are still mapped.
*/
for (i = 0, nr = 0; i < HPAGE_PMD_NR; i++) {
if (atomic_add_negative(-1, &page[i]._mapcount))
nr++;
}
+
+ /*
+ * Queue the page for deferred split if at least one small
+ * page of the compound page is unmapped, but at least one
+ * small page is still mapped.
+ */
+ if (nr && nr < HPAGE_PMD_NR)
+ deferred_split_huge_page(page);
} else {
nr = HPAGE_PMD_NR;
}
@@ -1305,10 +1313,8 @@ static void page_remove_anon_compound_rmap(struct page *page)
if (unlikely(PageMlocked(page)))
clear_page_mlock(page);
- if (nr) {
+ if (nr)
__mod_node_page_state(page_pgdat(page), NR_ANON_MAPPED, -nr);
- deferred_split_huge_page(page);
- }
}
/**