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* [PATCH] mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge()
@ 2020-03-11 17:24 Vlastimil Babka
  2020-03-11 18:20 ` Mike Kravetz
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Vlastimil Babka @ 2020-03-11 17:24 UTC (permalink / raw)
  To: Mike Kravetz, Andrew Morton
  Cc: linux-mm, linux-kernel, Vlastimil Babka, Kirill A . Shutemov

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


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2020-03-12  0:42 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-11 17:24 [PATCH] mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge() Vlastimil Babka
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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