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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1CEAC433EF for ; Wed, 18 May 2022 15:54:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0CC426B0073; Wed, 18 May 2022 11:54:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 055DC6B0074; Wed, 18 May 2022 11:54:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E37966B0075; Wed, 18 May 2022 11:54:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id D119F6B0073 for ; Wed, 18 May 2022 11:54:48 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 9ED7F321E2 for ; Wed, 18 May 2022 15:54:48 +0000 (UTC) X-FDA: 79479311856.02.237B402 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf25.hostedemail.com (Postfix) with ESMTP id 28D57A00C6 for ; Wed, 18 May 2022 15:54:23 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 65F181F8D9; Wed, 18 May 2022 15:54:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1652889286; 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=fT6DJGA2cOSTPqSQ5kMo5BIA56bUH+3rlEL1RMSElmw=; b=aWoZP/8KOjx9GL8rIoYGs6MZgz48DGxy4SoNyCoki2pVbuV9gffBgLWkZpR5smgYoFlh0h hD3/PDiDEcNjj4m7KDuM6QwX/pIbSn0SH8uV6l7rVl8wbLYKF1Hl/E+/6/2W1k561Cwvqv fWdHnKJVpUyT5CPfddB82CRcJiWz+nA= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 2CB6413A6D; Wed, 18 May 2022 15:54:46 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id aZMWCsYWhWL9WAAAMHmgww (envelope-from ); Wed, 18 May 2022 15:54:46 +0000 Date: Wed, 18 May 2022 17:54:44 +0200 From: Michal =?iso-8859-1?Q?Koutn=FD?= To: Roman Gushchin Cc: void@manifault.com, akpm@linux-foundation.org, cgroups@vger.kernel.org, hannes@cmpxchg.org, kernel-team@fb.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, shakeelb@google.com, tj@kernel.org, Richard Palethorpe Subject: Re: [PATCH 2/4] selftests: memcg: Expect no low events in unprotected sibling Message-ID: <20220518155444.GB22503@blackbody.suse.cz> References: <20220512174452.tr34tuh4k5jm6qjs@dev0025.ash9.facebook.com> <20220513171811.730-1-mkoutny@suse.com> <20220513171811.730-3-mkoutny@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 28D57A00C6 X-Stat-Signature: ympjj558xejxzykppt59kqehbgknaimc Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b="aWoZP/8K"; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf25.hostedemail.com: domain of mkoutny@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mkoutny@suse.com X-Rspam-User: X-HE-Tag: 1652889263-947401 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: Hi. On Fri, May 13, 2022 at 11:54:16AM -0700, Roman Gushchin wrote: > Hm, what are our plans here? Are we going to fix it soon-ish, or there > is still no agreement on how to proceed? Here are some of my ideas in random order so far and comments: 0) mask memory.events:low -> not a real fix 1) don't do SWAP_CLUSTER_MAX roundup -> won't solve sudden lift of protection 2) instead of SWAP_CLUSTER_MAX over-reclaim, do same under-reclaim -> same problem as 1) 3) update children_low_usage transactionally (after reclaim round is done) - ??? 4) don't recursively distribute residual protection in the same reclaim round - ??? 5) iterate siblings from highest to lowest protection - not a solution 6) assign only >SWAP_CLUSTER_MAX of residuum - need more info I'm discouraged by possible complexity of 3) or 4), while 6) is what I'd like to look more into. HTH, Michal