From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23971CA9EC9 for ; Fri, 1 Nov 2019 07:58:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00794217F9 for ; Fri, 1 Nov 2019 07:58:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730177AbfKAH62 (ORCPT ); Fri, 1 Nov 2019 03:58:28 -0400 Received: from mga17.intel.com ([192.55.52.151]:16169 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727059AbfKAH61 (ORCPT ); Fri, 1 Nov 2019 03:58:27 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 Nov 2019 00:58:27 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,254,1569308400"; d="scan'208";a="225962470" Received: from yhuang-dev.sh.intel.com ([10.239.159.29]) by fmsmga004.fm.intel.com with ESMTP; 01 Nov 2019 00:58:24 -0700 From: "Huang, Ying" To: Peter Zijlstra Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Andrew Morton , Michal Hocko , Rik van Riel , Mel Gorman , Ingo Molnar , Dave Hansen , Dan Williams , Fengguang Wu Subject: [RFC 02/10] autonuma: Reduce cache footprint when scanning page tables Date: Fri, 1 Nov 2019 15:57:19 +0800 Message-Id: <20191101075727.26683-3-ying.huang@intel.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191101075727.26683-1-ying.huang@intel.com> References: <20191101075727.26683-1-ying.huang@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Huang Ying In auto NUMA balancing page table scanning, if the pte_protnone() is true, the PTE needs not to be changed because it's in target state already. So other checking on corresponding struct page is unnecessary too. So, if we check pte_protnone() firstly for each PTE, we can avoid unnecessary struct page accessing, so that reduce the cache footprint of NUMA balancing page table scanning. In the performance test of pmbench memory accessing benchmark with 80:20 read/write ratio and normal access address distribution on a 2 socket Intel server with Optance DC Persistent Memory, perf profiling shows that the autonuma page table scanning time reduces from 1.23% to 0.97% (that is, reduced 21%) with the patch. Signed-off-by: "Huang, Ying" Cc: Andrew Morton Cc: Michal Hocko Cc: Rik van Riel Cc: Mel Gorman Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Dave Hansen Cc: Dan Williams Cc: Fengguang Wu Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org --- mm/mprotect.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/mprotect.c b/mm/mprotect.c index bf38dfbbb4b4..d69b9913388e 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -80,6 +80,10 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, if (prot_numa) { struct page *page; + /* Avoid TLB flush if possible */ + if (pte_protnone(oldpte)) + continue; + page = vm_normal_page(vma, addr, oldpte); if (!page || PageKsm(page)) continue; @@ -97,10 +101,6 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, if (page_is_file_cache(page) && PageDirty(page)) continue; - /* Avoid TLB flush if possible */ - if (pte_protnone(oldpte)) - continue; - /* * Don't mess with PTEs if page is already on the node * a single-threaded process is running on. -- 2.23.0