On 14.11.23 13:36, yang.yang29@xxxxxxxxxx wrote:
From: xu xin <xu.xin16@xxxxxxxxxx>
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@xxxxxxxxxx>
Reviewed-by: Yang Yang <yang.yang29@xxxxxxxxxx>
Can we please add a unit test to ksm_functional_tests.c so we actually
get it right this time?
--
Cheers,
David / dhildenb
