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 3ED72C433E0 for ; Wed, 10 Feb 2021 13:23:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0629764E0D for ; Wed, 10 Feb 2021 13:23:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230339AbhBJNX0 (ORCPT ); Wed, 10 Feb 2021 08:23:26 -0500 Received: from mx2.suse.de ([195.135.220.15]:40642 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231942AbhBJNWy (ORCPT ); Wed, 10 Feb 2021 08:22:54 -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=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: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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