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Subject[PATCH] mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge()
Date
Commit f1e61557f023 ("mm: pack compound_dtor and compound_order into one word
in struct page") changed compound_dtor from a pointer to an array index in
order to pack it. To check if page has the hugeltbfs compound_dtor, we can
just compare the index directly without fetching the function pointer.
Said commit did that with PageHuge() and we can do the same with PageHeadHuge()
to make the code a bit smaller and faster.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
mm/hugetlb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index dd8737a94bec..ba1ca452aa7f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1313,7 +1313,7 @@ int PageHeadHuge(struct page *page_head)
if (!PageHead(page_head))
return 0;

- return get_compound_page_dtor(page_head) == free_huge_page;
+ return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
}

pgoff_t __basepage_index(struct page *page)
--
2.25.1
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