From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ee0-f42.google.com (mail-ee0-f42.google.com [74.125.83.42]) by kanga.kvack.org (Postfix) with ESMTP id 74A8D6B003C for ; Tue, 3 Dec 2013 03:52:09 -0500 (EST) Received: by mail-ee0-f42.google.com with SMTP id e53so262041eek.29 for ; Tue, 03 Dec 2013 00:52:09 -0800 (PST) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTP id s8si44312514eeh.17.2013.12.03.00.52.08 for ; Tue, 03 Dec 2013 00:52:08 -0800 (PST) From: Mel Gorman Subject: [PATCH 07/15] mm: numa: Do not clear PMD during PTE update scan Date: Tue, 3 Dec 2013 08:51:54 +0000 Message-Id: <1386060721-3794-8-git-send-email-mgorman@suse.de> In-Reply-To: <1386060721-3794-1-git-send-email-mgorman@suse.de> References: <1386060721-3794-1-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Alex Thorlton Cc: Rik van Riel , Linux-MM , LKML , Mel Gorman If the PMD is flushed then a parallel fault in handle_mm_fault() will enter the pmd_none and do_huge_pmd_anonymous_page() path where it'll attempt to insert a huge zero page. This is wasteful so the patch avoids clearing the PMD when setting pmd_numa. Signed-off-by: Mel Gorman --- mm/huge_memory.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 203b5bc..d6c3bf4 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1474,20 +1474,24 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, if (__pmd_trans_huge_lock(pmd, vma) == 1) { pmd_t entry; - entry = pmdp_get_and_clear(mm, addr, pmd); + if (!prot_numa) { + entry = pmdp_get_and_clear(mm, addr, pmd); entry = pmd_modify(entry, newprot); BUG_ON(pmd_write(entry)); + set_pmd_at(mm, addr, pmd, entry); } else { struct page *page = pmd_page(*pmd); + entry = *pmd; /* only check non-shared pages */ if (page_mapcount(page) == 1 && !pmd_numa(*pmd)) { entry = pmd_mknuma(entry); + set_pmd_at(mm, addr, pmd, entry); } } - set_pmd_at(mm, addr, pmd, entry); + spin_unlock(&vma->vm_mm->page_table_lock); ret = 1; } -- 1.8.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org