From fd60775aea802beef444881ddfa111a4b73b1bbc Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Mon, 12 Dec 2016 16:42:20 -0800 Subject: mm, thp: avoid unlikely branches for split_huge_pmd While doing MADV_DONTNEED on a large area of thp memory, I noticed we encountered many unlikely() branches in profiles for each backing hugepage. This is because zap_pmd_range() would call split_huge_pmd(), which rechecked the conditions that were already validated, but as part of an unlikely() branch. Avoid the unlikely() branch when in a context where pmd is known to be good for __split_huge_pmd() directly. Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1610181600300.84525@chino.kir.corp.google.com Signed-off-by: David Rientjes Acked-by: Vlastimil Babka Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mempolicy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/mempolicy.c') diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 0b859af06b87..a6a27e5d6b14 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -496,7 +496,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr, page = pmd_page(*pmd); if (is_huge_zero_page(page)) { spin_unlock(ptl); - split_huge_pmd(vma, pmd, addr); + __split_huge_pmd(vma, pmd, addr, false, NULL); } else { get_page(page); spin_unlock(ptl); -- cgit v1.2.3