Commit 6c5c7b9f authored Sep 25, 2020 by Zi Yan Committed by Linus Torvalds Sep 26, 2020

mm/migrate: correct thp migration stats



PageTransHuge returns true for both thp and hugetlb, so thp stats was
counting both thp and hugetlb migrations.  Exclude hugetlb migration by
setting is_thp variable right.

Clean up thp handling code too when we are there.

Fixes: 1a5bae25 ("mm/vmstat: add events for THP migration without split")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lkml.kernel.org/r/20200917210413.1462975-1-zi.yan@sent.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent d3f7b1bb

mm/migrate.c

+3 −4

Original line number	Diff line number	Diff line
		@@ -1446,7 +1446,7 @@ retry:
		* Capture required information that might get lost
		* during migration.
		*/
		is_thp = PageTransHuge(page);
		is_thp = PageTransHuge(page) && !PageHuge(page);
		nr_subpages = thp_nr_pages(page);
		cond_resched();

		@@ -1472,7 +1472,7 @@ retry:
		* we encounter them after the rest of the list
		* is processed.
		*/
		if (PageTransHuge(page) && !PageHuge(page)) {
		if (is_thp) {
		lock_page(page);
		rc = split_huge_page_to_list(page, from);
		unlock_page(page);
		@@ -1481,8 +1481,7 @@ retry:
		nr_thp_split++;
		goto retry;
		}
		}
		if (is_thp) {

		nr_thp_failed++;
		nr_failed += nr_subpages;
		goto out;

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