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 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 28F4CC433E6 for ; Wed, 10 Feb 2021 13:22:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8FC3764E7C for ; Wed, 10 Feb 2021 13:22:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8FC3764E7C Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id F3BA16B0071; Wed, 10 Feb 2021 08:22:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EEC9D6B0072; Wed, 10 Feb 2021 08:22:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DDABE6B0073; Wed, 10 Feb 2021 08:22:08 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0250.hostedemail.com [216.40.44.250]) by kanga.kvack.org (Postfix) with ESMTP id C66366B0071 for ; Wed, 10 Feb 2021 08:22:08 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 9312A1646C for ; Wed, 10 Feb 2021 13:22:08 +0000 (UTC) X-FDA: 77802421536.21.stick24_171426827610 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id 6C62F185C5ACF for ; Wed, 10 Feb 2021 13:22:08 +0000 (UTC) X-HE-Tag: stick24_171426827610 X-Filterd-Recvd-Size: 3264 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Wed, 10 Feb 2021 13:22:07 +0000 (UTC) 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=1612963326; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=mJ/FLvZfbmUWb+LKB9yPiOaObzH1yEtwvoqn84DYlnI=; b=eO3AAJocFz7hUWdWkbQstm4HNlOwO/MjkW99G5zLU2b3IIfvsQhzApBML0ToHFuS6xgNL/ uZPG9HZCCiD+q8r5IdyP9+X3+dWknvVaunBpLXeNMC3u3JmGp8KkSCdqFy4NiIQkmsfbcb 2XTX5GvVTA8USYkqEGRDExmBMPodhhQ= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C932EAEAB; Wed, 10 Feb 2021 13:22:06 +0000 (UTC) Date: Wed, 10 Feb 2021 14:22:05 +0100 From: Michal Hocko To: Yu Zhao Cc: linux-mm@kvack.org, Sonny Rao , Jann Horn , Matthew Wilcox , Jesse Barnes , Linux Kernel Mailing List , page-reclaim@google.com Subject: Re: [page-reclaim] Augmented Page Reclaim Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Bogosity: Ham, tests=bogofilter, spamicity=0.000322, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed 10-02-21 00:12:38, Yu Zhao wrote: > On Tue, Feb 09, 2021 at 01:32:58PM -0800, Jesse Barnes wrote: > > > ====================== > > > Augmented Page Reclaim > > > ====================== > > > We would like to share a work with you and see if there is enough > > > interest to warrant a run for the mainline. This work is a part of > > > result from a decade of research and experimentation in memory > > > overcommit at Google: an augmented page reclaim that, in our > > > experience, is performant, versatile and, more importantly, simple. > > > > Per discussion on IRC, maybe some additional background would help. > > And I'll add more details to the doc included in the tree once I've > finished collecting feedback. Please be as specific as possible early. > > In looking at browser workloads on Chrome OS, we found that reclaim was: > > 1) too expensive in terms of CPU usage > > We have two general metrics for this item: CPU time spent on page > reclaim and (direct) page reclaim latency. CPU usage is important to > everybody but latency is also quite important for phones, laptops, > etc. While this is true in general, more details would be more than welcome. What is the source of the additional overhead and how does your work address that? This applies to most of other areas you are covering here and in the original cover letter. Especially when you do not plan to build on an existing code and rather plan to do things considerably differently. I confess I haven't checked your repository but it would have been much better to post a patch series -- Michal Hocko SUSE Labs