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 12614C433F5 for ; Wed, 15 Dec 2021 16:48:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 651F16B0071; Wed, 15 Dec 2021 11:48:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 601416B0073; Wed, 15 Dec 2021 11:48:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4A2596B0074; Wed, 15 Dec 2021 11:48:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.a.hostedemail.com [64.99.140.24]) by kanga.kvack.org (Postfix) with ESMTP id 3782C6B0071 for ; Wed, 15 Dec 2021 11:48:09 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id E75352033F for ; Wed, 15 Dec 2021 16:47:58 +0000 (UTC) X-FDA: 78920610636.05.776D045 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by imf28.hostedemail.com (Postfix) with ESMTP id D9E3AC0011 for ; Wed, 15 Dec 2021 16:47:57 +0000 (UTC) Date: Wed, 15 Dec 2021 17:47:54 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1639586875; 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=PWKQmVaUmlhlu4LBLW0y54JVGs+emTP6yYulZAfEBlg=; b=2IFozc2UCxRwnxaxcLhssB5iej7201xbCCVh3mTjGNBMlWNimNqL7TkMlTvKyGFxza0wth PyNePnpWcaCgpgpYKdzHl9bzT1M9BO/3eF1UmmO+4+cmsF1t+7/oVp4M+cSY8O64//i9dP kYR02Dg4IhK8BEvyds5Ex1knUiQ5Oa/LxRn8BWMgFhswIKoanv+4/94SkrsTeeXAzetmo3 lECFr4EbWVuF9LZBzWs9zGRYm+QZ76vGw+xCBBhTS5o17FB7atEJn2kDBCOWy0eYyuAF3T LoUr8FQaYsOnNZlMsrxgagkHtCbgn54lnXB7SJyJeTHTVlGEJXUSJnIdKHO3Eg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1639586875; 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=PWKQmVaUmlhlu4LBLW0y54JVGs+emTP6yYulZAfEBlg=; b=0Siez4oA1M3vHIh4cpe9gkN+9TKepZa4ecFRf7RzuKjMHsn5DxCtj3g7bRl6LFklw2Q0k5 b3xLWqKEywIERQAg== From: Sebastian Andrzej Siewior To: Michal Hocko Cc: Johannes Weiner , cgroups@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Thomas Gleixner , Vladimir Davydov , Waiman Long Subject: Re: [PATCH] mm/memcontrol: Disable on PREEMPT_RT Message-ID: References: <20211207155208.eyre5svucpg7krxe@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: D9E3AC0011 X-Stat-Signature: sanq9gixgr4e4i97fmkp8yt76hb7yuz8 Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=linutronix.de header.s=2020 header.b=2IFozc2U; dkim=pass header.d=linutronix.de header.s=2020e header.b=0Siez4oA; spf=pass (imf28.hostedemail.com: domain of bigeasy@linutronix.de designates 193.142.43.55 as permitted sender) smtp.mailfrom=bigeasy@linutronix.de; dmarc=pass (policy=none) header.from=linutronix.de X-HE-Tag: 1639586877-792940 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: On 2021-12-13 11:08:26 [+0100], Michal Hocko wrote: > On Fri 10-12-21 16:22:01, Sebastian Andrzej Siewior wrote: > [...] > I am sorry but I didn't get to read and digest the rest of the message > yet. Let me just point out this >=20 > > The problematic part here is mem_cgroup_tree_per_node::lock which can > > not be acquired with disabled interrupts on PREEMPT_RT. The "locking > > scope" is not always clear to me. Also, if it is _just_ the counter, > > then we might solve this differently. >=20 > I do not think you should be losing sleep over soft limit reclaim. This > is certainly not something to be used for RT workloads and rather than > touching that code I think it makes some sense to simply disallow soft > limit with RT enabled (i.e. do not allow to set any soft limit). Okay. So instead of disabling it entirely you suggest I should take another stab at it? Okay. Disabling softlimit, where should I start with it? Should mem_cgroup_write() for RES_SOFT_LIMIT always return an error or something else? In the meantime I try to swap in my memcg memory=E2=80=A6 Sebastian