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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 8A1E8C07E85 for ; Fri, 7 Dec 2018 09:48:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5B2BE208E7 for ; Fri, 7 Dec 2018 09:48:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B2BE208E7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.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 S1726038AbeLGJsX (ORCPT ); Fri, 7 Dec 2018 04:48:23 -0500 Received: from foss.arm.com ([217.140.101.70]:40476 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726005AbeLGJsX (ORCPT ); Fri, 7 Dec 2018 04:48:23 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0D6A7EBD; Fri, 7 Dec 2018 01:48:23 -0800 (PST) Received: from arrakis.emea.arm.com (arrakis.cambridge.arm.com [10.1.196.113]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1DD693F59C; Fri, 7 Dec 2018 01:48:21 -0800 (PST) Date: Fri, 7 Dec 2018 09:48:19 +0000 From: Catalin Marinas To: Oscar Salvador Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm, kmemleak: Little optimization while scanning Message-ID: <20181207094819.GA23085@arrakis.emea.arm.com> 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: Mutt/1.10.1 (2018-07-13) 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 Acked-by: Catalin Marinas