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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A3E1C433FE for ; Fri, 3 Dec 2021 14:01:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1381312AbhLCOEp (ORCPT ); Fri, 3 Dec 2021 09:04:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237277AbhLCOEk (ORCPT ); Fri, 3 Dec 2021 09:04:40 -0500 Received: from vulcan.natalenko.name (vulcan.natalenko.name [IPv6:2001:19f0:6c00:8846:5400:ff:fe0c:dfa0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 68E95C06173E for ; Fri, 3 Dec 2021 06:01:16 -0800 (PST) Received: from spock.localnet (unknown [83.148.33.151]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by vulcan.natalenko.name (Postfix) with ESMTPSA id 64524CD725E; Fri, 3 Dec 2021 15:01:10 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=natalenko.name; s=dkim-20170712; t=1638540070; h=from:from:reply-to:subject:subject: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=2nhD4zra9xotXQb3VuD0lCqOmyZLq0VjR4YeA+r1z2U=; b=p7usrMbkAXabAriuPUDQkjnERX7qsoPkVejZuXN+DdzWEpWdfyHLcO6qkUqkFMhnj5fWMK g66TAHWHFLc18LHnjInRbw7WyLAuSo/fnTveYakx8m58uVKZmWFIpcOnW8JY9Mr3uKhP+O Zs/RPt/7vIiOPfz0lzdddNeDYdZJLZA= From: Oleksandr Natalenko To: ValdikSS , Andrew Morton Cc: Alexey Avramov , linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, corbet@lwn.net, mcgrof@kernel.org, keescook@chromium.org, yzaikin@google.com, kernel@xanmod.org, aros@gmx.com, hakavlad@gmail.com, Yu Zhao Subject: Re: [PATCH] mm/vmscan: add sysctl knobs for protecting the working set Date: Fri, 03 Dec 2021 15:01:08 +0100 Message-ID: <4776971.31r3eYUQgx@natalenko.name> In-Reply-To: <20211202135824.33d2421bf5116801cfa2040d@linux-foundation.org> References: <20211130201652.2218636d@mail.inbox.lv> <2dc51fc8-f14e-17ed-a8c6-0ec70423bf54@valdikss.org.ru> <20211202135824.33d2421bf5116801cfa2040d@linux-foundation.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. On =C4=8Dtvrtek 2. prosince 2021 22:58:24 CET Andrew Morton wrote: > On Thu, 2 Dec 2021 21:05:01 +0300 ValdikSS wrote: > > This patchset is surprisingly effective and very useful for low-end PC > > with slow HDD, single-board ARM boards with slow storage, cheap Android > > smartphones with limited amount of memory. It almost completely prevents > > thrashing condition and aids in fast OOM killer invocation. > >=20 > > The similar file-locking patch is used in ChromeOS for nearly 10 years > > but not on stock Linux or Android. It would be very beneficial for > > lower-performance Android phones, SBCs, old PCs and other devices. > >=20 > > With this patch, combined with zram, I'm able to run the following > > software on an old office PC from 2007 with __only 2GB of RAM__ > >=20 > > simultaneously: > > * Firefox with 37 active tabs (all data in RAM, no tab unloading) > > * Discord > > * Skype > > * LibreOffice with the document opened > > * Two PDF files (14 and 47 megabytes in size) > >=20 > > And the PC doesn't crawl like a snail, even with 2+ GB in zram! > > Without the patch, this PC is barely usable. > > Please watch the video: > > https://notes.valdikss.org.ru/linux-for-old-pc-from-2007/en/ >=20 > This is quite a condemnation of the current VM. It shouldn't crawl > like a snail. >=20 > The patch simply sets hard limits on page reclaim's malfunctioning. > I'd prefer that reclaim not malfunction :( >=20 > That being said, I can see that a blunt instrument like this would be > useful. >=20 > I don't think that the limits should be "N bytes on the current node". > Nodes can have different amounts of memory so I expect it should scale > the hard limits on a per-node basis. And of course, the various zones > have different size as well. Probably not. To my understanding, the limits should roughly correspond to= =20 what you see after executing this: ``` $ echo 1 | sudo tee /proc/sys/vm/drop_caches; grep -F 'Active(file)' /proc/ meminfo ``` IMO, this has nothing to do with the size of the node. > We do already have a lot of sysctls for controlling these sort of > things. Was much work put into attempting to utilize the existing > sysctls to overcome these issues? =2D-=20 Oleksandr Natalenko (post-factum)