Commit a980df33 authored Jun 03, 2020 by Kirill A. Shutemov Committed by Linus Torvalds Jun 03, 2020

khugepaged: drain all LRU caches before scanning pages



Having a page in LRU add cache offsets page refcount and gives
false-negative on PageLRU().  It reduces collapse success rate.

Drain all LRU add caches before scanning.  It happens relatively rare and
should not disturb the system too much.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: http://lkml.kernel.org/r/20200416160026.16538-4-kirill.shutemov@linux.intel.com


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

parent ffe945e6

mm/khugepaged.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -2079,6 +2079,8 @@ static void khugepaged_do_scan(void)

		barrier(); /* write khugepaged_pages_to_scan to local stack */

		lru_add_drain_all();

		while (progress < pages) {
		if (!khugepaged_prealloc_page(&hpage, &wait))
		break;

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