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From: Vlastimil Babka <>
To: Mike Kravetz <>,
	Andrew Morton <>
	Vlastimil Babka <>,
	"Kirill A . Shutemov" <>
Subject: [PATCH] mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge()
Date: Wed, 11 Mar 2020 18:24:40 +0100	[thread overview]
Message-ID: <> (raw)

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 <>
Cc: Mike Kravetz <>
Cc: Kirill A. Shutemov <>
 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)

             reply	other threads:[~2020-03-11 17:25 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-11 17:24 Vlastimil Babka [this message]
2020-03-11 18:20 ` Mike Kravetz
2020-03-11 19:25 ` David Rientjes
2020-03-12  0:41 ` Kirill A. Shutemov
2020-03-12  0:42   ` Kirill A. Shutemov

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