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authorHugh Dickins <hughd@google.com>2021-07-01 04:52:04 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-07-01 06:47:30 +0300
commitab02c252c8609c73ff2897c7e961b631e8bd409c (patch)
tree4219b9d4b54a6a37cb4f52115fc4f1bd1988727a /mm/huge_memory.c
parent1fb08ac63beedf58e2ae9f229ea1f9474949a185 (diff)
downloadlinux-ab02c252c8609c73ff2897c7e961b631e8bd409c.tar.xz
mm/thp: remap_page() is only needed on anonymous THP
THP splitting's unmap_page() only sets TTU_SPLIT_FREEZE when PageAnon, and migration entries are only inserted when TTU_MIGRATION (unused here) or TTU_SPLIT_FREEZE is set: so it's just a waste of time for remap_page() to search for migration entries to remove when !PageAnon. Link: https://lkml.kernel.org/r/f987bc44-f28e-688d-2424-b4722153ed8@google.com Fixes: baa355fd3314 ("thp: file pages support for split_huge_page()") Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Jan Kara <jack@suse.cz> Cc: Jue Wang <juew@google.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Zi Yan <ziy@nvidia.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.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index dc0a0c82a5ac..503c8e1aecc6 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2307,6 +2307,7 @@ static void unmap_page(struct page *page)
VM_BUG_ON_PAGE(!PageHead(page), page);
+ /* If TTU_SPLIT_FREEZE is ever extended to file, update remap_page() */
if (PageAnon(page))
ttu_flags |= TTU_SPLIT_FREEZE;
@@ -2318,6 +2319,10 @@ static void unmap_page(struct page *page)
static void remap_page(struct page *page, unsigned int nr)
{
int i;
+
+ /* If TTU_SPLIT_FREEZE is ever extended to file, remove this check */
+ if (!PageAnon(page))
+ return;
if (PageTransHuge(page)) {
remove_migration_ptes(page, page, true);
} else {