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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 4DEE7C433E6 for ; Wed, 10 Feb 2021 13:16:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1913B64E7C for ; Wed, 10 Feb 2021 13:16:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231438AbhBJNPz (ORCPT ); Wed, 10 Feb 2021 08:15:55 -0500 Received: from mx2.suse.de ([195.135.220.15]:33352 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229710AbhBJNPh (ORCPT ); Wed, 10 Feb 2021 08:15:37 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1612962889; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MiX2gkzarTK0h+lISZ1n2kae0qwJVwGheDzNtJatgj4=; b=oGTLpdlTv9kpK7PGKvpr+uzOynnvsduvfrSgh/g1amIqnkadq/SgrIDv6zZ95TA907qy0F DexjlY/nfJEG67SjG26HNg8S7ApCGw62B43HlBlmUEGVPrem+EXc7MU6NWejTdLP0mUn3H 65fbIwFlTG/wO25sBtvT0Epxttd7ycU= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C8332AC97; Wed, 10 Feb 2021 13:14:48 +0000 (UTC) Date: Wed, 10 Feb 2021 14:14:46 +0100 From: Michal Hocko To: zhou xianrong Cc: iamjoonsoo.kim@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, rostedt@goodmis.org, mingo@redhat.com, vbabka@suse.cz, rientjes@google.com, willy@linux.intel.com, pankaj.gupta.linux@gmail.com, bhe@redhat.com, ying.huang@intel.com, minchan@kernel.org, ruxian.feng@transsion.com, kai.cheng@transsion.com, zhao.xu@transsion.com, yunfeng.lan@transsion.com, zhouxianrong@tom.com, zhou xianrong Subject: Re: [PATCH] kswapd: no need reclaim cma pages triggered by unmovable allocation Message-ID: References: <20210209082313.21969-1-xianrong_zhou@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 10-02-21 12:07:57, zhou xianrong wrote: > > On 2021/2/9 下午5:23, Michal Hocko wrote: > > On Tue 09-02-21 16:23:13, zhou wrote: > > > From: zhou xianrong > > > > > > For purpose of better migration cma pages are allocated after > > > failure movalbe allocations and are used normally for file pages > > > or anonymous pages. > > > > > > In reclaim path so many cma pages if configurated are reclaimed > > > from lru lists in kswapd mainly or direct reclaim triggered by > > > unmovable or reclaimable allocations. But these cma pages can not > > > be used by original unmovable or reclaimable allocations. So the > > > reclaim are unnecessary. > > > > > > In a same system if the cma pages were configurated to large then > > > more failture unmovable (vmalloc etc.) or reclaimable (slab etc.) > > > allocations are arised and then more kswapd rounds are triggered > > > and then more cma pages are reclaimed. > > Could you be more specific? Do you have any numbers and an example > > configuration when this is visible? > It should be implicit. Right but the scale of the problem is an important part of _any_ patch justification. -- Michal Hocko SUSE Labs