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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 CD697CA9EBB for ; Thu, 24 Oct 2019 05:34:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7607821872 for ; Thu, 24 Oct 2019 05:34:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7607821872 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DF4A56B0005; Thu, 24 Oct 2019 01:34:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DA4E06B0006; Thu, 24 Oct 2019 01:34:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CB9F56B0007; Thu, 24 Oct 2019 01:34:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0087.hostedemail.com [216.40.44.87]) by kanga.kvack.org (Postfix) with ESMTP id A41EC6B0005 for ; Thu, 24 Oct 2019 01:34:51 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 25B51180ACF84 for ; Thu, 24 Oct 2019 05:34:51 +0000 (UTC) X-FDA: 76077563982.28.team44_2a40ac3affa30 X-HE-Tag: team44_2a40ac3affa30 X-Filterd-Recvd-Size: 2943 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Thu, 24 Oct 2019 05:34:50 +0000 (UTC) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Oct 2019 22:34:49 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,223,1569308400"; d="scan'208";a="192074234" Received: from shbuild999.sh.intel.com (HELO localhost) ([10.239.147.113]) by orsmga008.jf.intel.com with ESMTP; 23 Oct 2019 22:34:46 -0700 Date: Thu, 24 Oct 2019 13:34:45 +0800 From: Feng Tang To: Qian Cai Cc: Waiman Long , Andrew Morton , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Johannes Weiner , Michal Hocko , Roman Gushchin , Vlastimil Babka , Konstantin Khlebnikov , Jann Horn , Song Liu , Greg Kroah-Hartman , Rafael Aquini Subject: Re: [PATCH] mm/vmstat: Reduce zone lock hold time when reading /proc/pagetypeinfo Message-ID: <20191024053445.GB42124@shbuild999.sh.intel.com> References: <20191024033313.GA42124@shbuild999.sh.intel.com> <15BA6C88-21C1-4BF3-BB10-2A207AEBB401@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <15BA6C88-21C1-4BF3-BB10-2A207AEBB401@lca.pw> User-Agent: Mutt/1.5.24 (2015-08-30) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Oct 24, 2019 at 12:34:41PM +0800, Qian Cai wrote: > > > > On Oct 23, 2019, at 11:33 PM, Feng Tang wrote: > > > > We have been using the /proc/pagetypeinfo for debugging, mainly for > > client platforms like phones/tablets. We met problems like very slow > > system response or OOM things, and many of them could be related with > > memory pressure or fragmentation issues, where monitoring /proc/pagetypeinfo > > will be very useful for debugging. > > This description of use case is rather vague. Which part of the information in that file is critical to debug an OOM or slow system that is not readily available in places like /proc/zoneinfo, /proc/buddyinfo, sysrq-m, or OOM trace etc? One example is, there was a platform with limited DRAM, so it preset some CMA memory for camera's big buffer allocation use, while it let these memory to be shared by others when camera was not used. And after long time running, the cma region got fragmented and camera app started to fail due to the buffer allocation failure. And during debugging, we kept monitoring the buddy info for different migrate types. Thanks, Feng