Messages in this thread | | | Date | Tue, 14 Nov 2023 14:02:22 +0100 | Subject | Re: [PATCH] ksm: delay the check of splitting compound pages | From | David Hildenbrand <> |
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On 14.11.23 13:36, yang.yang29@zte.com.cn wrote: > From: xu xin <xu.xin16@zte.com.cn> > > Background > ========== > When trying to merge two pages, it may fail because the two pages > belongs to the same compound page and split_huge_page fails due to > the incorrect reference to the page. To solve the problem, the commit > 77da2ba0648a4 ("mm/ksm: fix interaction with THP") tries to split the > compound page after try_to_merge_two_pages() fails and put_page in > that case. However it is too early to calculate of the variable 'split' which > indicates whether the two pages belongs to the same compound page. > > What to do > ========== > If try_to_merge_two_pages() succeeds, there is no need to check whether > to splitting compound pages. So we delay the check of splitting compound > pages until try_to_merge_two_pages() fails, which can improve the > processing efficiency of cmp_and_merge_page() a little. > > Signed-off-by: xu xin <xu.xin16@zte.com.cn> > Reviewed-by: Yang Yang <yang.yang29@zte.com.cn>
Can we please add a unit test to ksm_functional_tests.c so we actually get it right this time?
-- Cheers,
David / dhildenb
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