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=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 7BC42C67838 for ; Fri, 7 Dec 2018 04:15:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 34B402082D for ; Fri, 7 Dec 2018 04:15:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="WjVTZGAI" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 34B402082D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726021AbeLGEPd (ORCPT ); Thu, 6 Dec 2018 23:15:33 -0500 Received: from mail-ed1-f67.google.com ([209.85.208.67]:39954 "EHLO mail-ed1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725950AbeLGEPd (ORCPT ); Thu, 6 Dec 2018 23:15:33 -0500 Received: by mail-ed1-f67.google.com with SMTP id d3so2612540edx.7 for ; Thu, 06 Dec 2018 20:15:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-disposition:in-reply-to:user-agent; bh=fYnV/EO4xTIHV6ubHlOYZNuYjGOKKK4VA8dvnyVZ/vI=; b=WjVTZGAI5mU/xUcQbxIH3olcK8m1Jg5qZJ+SyM5GOUoC4b87aXQcirbTyEfIOVh8CZ KiJgOm0lBJ/Q+W5hoVvttUJq+HbP5PeKtdMjCxEDZjUh4nl0Q+YIs8o41ma22pn8BpXc ngrnHh1Om9363Y+qWDOjGlPLK/x9MKkn74zzejSprD3nw3TTZwyt+BlmpD5QpCfjnZu0 gVonRFh8fwsw6qon9eXs4/72V0++eAmPnD8fWTW6tqWgPKR3jWOPuGaxzcsSq4m6dVOo 3GCsCg8q792ieFgFyHGOxNiPs6GNnULl1GRuXc5srPSMQ+BTsO+BySKNsN6VQ33FIMzb NCLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:reply-to :references:mime-version:content-disposition:in-reply-to:user-agent; bh=fYnV/EO4xTIHV6ubHlOYZNuYjGOKKK4VA8dvnyVZ/vI=; b=KvQpJEApLfyJNDqK8YiVM5TCmLMkdjsg7PMzxvifqvdU7aKyXEFgSkvrL1P8DpR1Pj DBZkWLfTfGKzZHot1co0KItUCFjJxfnufPQ/79KyHdApF0F0kSrBjiGp671+kUQT2Xg1 Nl6zlOzcSNsbgLQn6wA3p3kSOBJ5U4YLjtsGrtHiEeUk4cxYQ80J9eIICNp+gbtvdLvR IEARYdgT54o5ALw0/DwjXdjI4H/wMFeTEmj0LWgPa++qnMHvIOB9tusW84wBEfegRXOm EQNZ3dBRhq34Sxd69PgngA0QYKfs6ZMNZuICPhMSnAH13Xivi1DVmF/7gPRr4e2tDR/K Kchg== X-Gm-Message-State: AA+aEWZi5BYq0GkTGIb1YQ8zE24FQxHHYtSFGokZ6/tTPb6euGIBjIDp Q5wrVmecKDpZuqu7IRrCBBkPllSI X-Google-Smtp-Source: AFSGD/WHaO/M/QmusgsSTCZd3Fv72Dwcq9GBWDzNlLU3wHnei0AeR9iogT07LcayEwYlQq4xOpvD+Q== X-Received: by 2002:a50:ba3d:: with SMTP id g58mr818433edc.35.1544156130409; Thu, 06 Dec 2018 20:15:30 -0800 (PST) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id v43sm683219edc.18.2018.12.06.20.15.28 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 06 Dec 2018 20:15:29 -0800 (PST) Date: Fri, 7 Dec 2018 04:15:28 +0000 From: Wei Yang To: Oscar Salvador Cc: akpm@linux-foundation.org, catalin.marinas@arm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm, kmemleak: Little optimization while scanning Message-ID: <20181207041528.xs4xnw6vpsbu5csx@master> Reply-To: Wei Yang References: <20181206131918.25099-1-osalvador@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181206131918.25099-1-osalvador@suse.de> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 06, 2018 at 02:19:18PM +0100, Oscar Salvador wrote: >kmemleak_scan() goes through all online nodes and tries >to scan all used pages. >We can do better and use pfn_to_online_page(), so in case we have >CONFIG_MEMORY_HOTPLUG, offlined pages will be skiped automatically. >For boxes where CONFIG_MEMORY_HOTPLUG is not present, pfn_to_online_page() >will fallback to pfn_valid(). > >Another little optimization is to check if the page belongs to the node >we are currently checking, so in case we have nodes interleaved we will >not check the same pfn multiple times. > >I ran some tests: > >Add some memory to node1 and node2 making it interleaved: > >(qemu) object_add memory-backend-ram,id=ram0,size=1G >(qemu) device_add pc-dimm,id=dimm0,memdev=ram0,node=1 >(qemu) object_add memory-backend-ram,id=ram1,size=1G >(qemu) device_add pc-dimm,id=dimm1,memdev=ram1,node=2 >(qemu) object_add memory-backend-ram,id=ram2,size=1G >(qemu) device_add pc-dimm,id=dimm2,memdev=ram2,node=1 > >Then, we offline that memory: > # for i in {32..39} ; do echo "offline" > /sys/devices/system/node/node1/memory$i/state;done > # for i in {48..55} ; do echo "offline" > /sys/devices/system/node/node1/memory$i/state;don > # for i in {40..47} ; do echo "offline" > /sys/devices/system/node/node2/memory$i/state;done > >And we run kmemleak_scan: > > # echo "scan" > /sys/kernel/debug/kmemleak > >before the patch: > >kmemleak: time spend: 41596 us > >after the patch: > >kmemleak: time spend: 34899 us > >Signed-off-by: Oscar Salvador >--- > mm/kmemleak.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > >diff --git a/mm/kmemleak.c b/mm/kmemleak.c >index 877de4fa0720..5ce1e6a46d77 100644 >--- a/mm/kmemleak.c >+++ b/mm/kmemleak.c >@@ -113,6 +113,7 @@ > #include > #include > >+ This one maybe not necessary. > /* > * Kmemleak configuration and common defines. > */ >@@ -1547,11 +1548,14 @@ static void kmemleak_scan(void) > unsigned long pfn; > > for (pfn = start_pfn; pfn < end_pfn; pfn++) { >- struct page *page; >+ struct page *page = pfn_to_online_page(pfn); >+ >+ if (!page) >+ continue; > >- if (!pfn_valid(pfn)) >+ /* only scan pages belonging to this node */ >+ if (page_to_nid(page) != i) > continue; Not farmiliar with this situation. Is this often? >- page = pfn_to_page(pfn); > /* only scan if page is in use */ > if (page_count(page) == 0) > continue; >-- >2.13.7 -- Wei Yang Help you, Help me