From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f175.google.com (mail-wi0-f175.google.com [209.85.212.175]) by kanga.kvack.org (Postfix) with ESMTP id AF825900017 for ; Fri, 21 Nov 2014 08:58:06 -0500 (EST) Received: by mail-wi0-f175.google.com with SMTP id l15so12143814wiw.8 for ; Fri, 21 Nov 2014 05:58:05 -0800 (PST) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id bq18si10214628wib.25.2014.11.21.05.58.05 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 21 Nov 2014 05:58:05 -0800 (PST) From: Mel Gorman Subject: [PATCH 10/10] mm: numa: Avoid unnecessary TLB flushes when setting NUMA hinting entries Date: Fri, 21 Nov 2014 13:57:48 +0000 Message-Id: <1416578268-19597-11-git-send-email-mgorman@suse.de> In-Reply-To: <1416578268-19597-1-git-send-email-mgorman@suse.de> References: <1416578268-19597-1-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Linux Kernel , Linux-MM , LinuxPPC-dev Cc: Aneesh Kumar , Hugh Dickins , Dave Jones , Rik van Riel , Ingo Molnar , Kirill Shutemov , Sasha Levin , Benjamin Herrenschmidt , Paul Mackerras , Linus Torvalds , Mel Gorman If a PTE or PMD is already marked NUMA when scanning to mark entries for NUMA hinting then it is not necessary to update the entry and incur a TLB flush penalty. Avoid the avoidhead where possible. Signed-off-by: Mel Gorman --- mm/huge_memory.c | 14 ++++++++------ mm/mprotect.c | 4 ++++ 2 files changed, 12 insertions(+), 6 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 8546654..f2bf521 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1524,12 +1524,14 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, return 0; } - ret = 1; - entry = pmdp_get_and_clear_notify(mm, addr, pmd); - entry = pmd_modify(entry, newprot); - ret = HPAGE_PMD_NR; - set_pmd_at(mm, addr, pmd, entry); - BUG_ON(pmd_write(entry)); + if (!prot_numa || !pmd_protnone(*pmd)) { + ret = 1; + entry = pmdp_get_and_clear_notify(mm, addr, pmd); + entry = pmd_modify(entry, newprot); + ret = HPAGE_PMD_NR; + set_pmd_at(mm, addr, pmd, entry); + BUG_ON(pmd_write(entry)); + } spin_unlock(ptl); } diff --git a/mm/mprotect.c b/mm/mprotect.c index 33dfafb..109e7aa 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -86,6 +86,10 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, page = vm_normal_page(vma, addr, oldpte); if (!page || PageKsm(page)) continue; + + /* Avoid TLB flush if possible */ + if (pte_protnone(oldpte)) + continue; } ptent = ptep_modify_prot_start(mm, addr, pte); -- 2.1.2 -- 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