From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753727AbaLDLYw (ORCPT ); Thu, 4 Dec 2014 06:24:52 -0500 Received: from cantor2.suse.de ([195.135.220.15]:50479 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753854AbaLDLYv (ORCPT ); Thu, 4 Dec 2014 06:24:51 -0500 From: Mel Gorman To: Andrew Morton Cc: Aneesh Kumar , Hugh Dickins , Dave Jones , Rik van Riel , Ingo Molnar , Kirill Shutemov , Sasha Levin , Benjamin Herrenschmidt , Paul Mackerras , Linus Torvalds , Linux Kernel , Linux-MM , LinuxPPC-dev , Mel Gorman Subject: [PATCH 10/10] mm: numa: Avoid unnecessary TLB flushes when setting NUMA hinting entries Date: Thu, 4 Dec 2014 11:24:33 +0000 Message-Id: <1417692273-27170-11-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 2.1.2 In-Reply-To: <1417692273-27170-1-git-send-email-mgorman@suse.de> References: <1417692273-27170-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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