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 2E12AC61DA4 for ; Tue, 14 Feb 2023 08:31:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 999C4280001; Tue, 14 Feb 2023 03:31:37 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 922776B0074; Tue, 14 Feb 2023 03:31:37 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7C2DF280001; Tue, 14 Feb 2023 03:31:37 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 696A06B0073 for ; Tue, 14 Feb 2023 03:31:37 -0500 (EST) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 217FA1207A0 for ; Tue, 14 Feb 2023 08:31:37 +0000 (UTC) X-FDA: 80465228634.15.2CA22C4 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf05.hostedemail.com (Postfix) with ESMTP id 55C0D100023 for ; Tue, 14 Feb 2023 08:31:34 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=LaLBveM8; spf=pass (imf05.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1676363494; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=AA7VF9zg98MXho4gucCPM2gEisZygGvmQmXCbTESl2A=; b=icjBziH037Yi+vkgxZjc0iwaxwi1wY0NdNWkHPWqRLI6mHDWTi3Y/vBy+8pnzTic+FmNL5 1PuUNlnASptzNZt0+2wUB8ZiYARQvAsN2Bj1pvU2ZpV1qrR3/hL9L/Sy9+Skct/KOJStzn YY4Bs1gCWitBy1EpjMYHhhS9QJM/4cY= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=LaLBveM8; spf=pass (imf05.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1676363494; a=rsa-sha256; cv=none; b=PYEB1w5Lk5GIpEbJ+XWZT3CsWuQ0Tn0eiPA0HsH18sBPbXVPW3/rPcM4oOH0djvusnfYZO BlOfS7jxPX9ERp4K2wBzTDhENzdbhPA2EwAflysLpmV0ZGiGNUkjP9N0UW3p+54CecIELg q0BifLOkP/yK+Rc2s2ASadkxMHmqTY0= 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-out1.suse.de (Postfix) with ESMTPS id B30BD336B8; Tue, 14 Feb 2023 08:31:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1676363492; 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=AA7VF9zg98MXho4gucCPM2gEisZygGvmQmXCbTESl2A=; b=LaLBveM8vNL7Zh+CPiPZh7amtYKo04GzYyXROb79ZaqlAOVJtXfC1l2ZuwdBEl7qlXgQJN h+IJ8LCPJtexw4SGiu3AyuC7uIelWUIPFgAOq8J1IbjCc2tWS4eRdLyhFUQ/eE7pPZz2ep EChxdkqNj9aKwjt/DJcsK/23wvPVTx8= 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 A2C93138E3; Tue, 14 Feb 2023 08:31:32 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id ikrpJuRG62OaKwAAMHmgww (envelope-from ); Tue, 14 Feb 2023 08:31:32 +0000 Date: Tue, 14 Feb 2023 09:31:32 +0100 From: Michal Hocko To: Roman Gushchin Cc: Andrew Morton , linux-kernel@vger.kernel.org, Johannes Weiner , Shakeel Butt , Muchun Song , Dennis Zhou , linux-mm@kvack.org Subject: Re: [PATCH] mm: memcontrol: rename memcg_kmem_enabled() Message-ID: References: <20230213192922.1146370-1-roman.gushchin@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230213192922.1146370-1-roman.gushchin@linux.dev> X-Stat-Signature: aqganfgbxn37716g19u3turwugj8q9g9 X-Rspam-User: X-Rspamd-Queue-Id: 55C0D100023 X-Rspamd-Server: rspam06 X-HE-Tag: 1676363494-87423 X-HE-Meta: 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 3tLzZk0k 2u595ez3IBNpRsEFekieIa81jMv+uVrUUv0Q1P+XneKJIA+zcnuErw5LoRi5k+v1ukZVUNfg8Bz3cOstUmCWFAwWB0OoLFPbDSASUjTFZheO+QbuI02nVE/dCulWvSog9M9AHSJK2m3Nv+zRtlTF8tU9SUdWXFl47Qitd+JhXeyTgvSdvE/+h7GSRKnQl06CRYCwXPh/bd77ON09NKDxByp5rQGZdUCkzakGq6G0eyHJOdohxqIkwf8kqhBmkA0KENO+R25yrQq58HRmmRew9yz9mTrN+xXZqaLu7kacObpbG5Qxfg/Nt8d9m+fCOiEzaQymyJ9ZeEvX4y5y7KOXiT424Gf5p9qDkj0sQ2ooOZivB59r8CD6JBm15s/yvyzaE2HLn5JeSn0EOM+Wfuh92hbTJfYJDg1EieyhC2Nb+asVf5kyHHHK4ylKaFFsKiEaz7IUnd6W0S8CQcVx4Pwd4n4IDlA== 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 Mon 13-02-23 11:29:22, Roman Gushchin wrote: > Currently there are two kmem-related helper functions with a confusing > semantics: memcg_kmem_enabled() and mem_cgroup_kmem_disabled(). > > The problem is that an obvious expectation > memcg_kmem_enabled() == !mem_cgroup_kmem_disabled(), > can be false. > > mem_cgroup_kmem_disabled() is similar to mem_cgroup_disabled(): it > returns true only if CONFIG_MEMCG_KMEM is not set or the kmem > accounting is disabled using a boot time kernel option > "cgroup.memory=nokmem". It never changes the value dynamically. > > memcg_kmem_enabled() is different: it always returns false until > the first non-root memory cgroup will get online (assuming the kernel > memory accounting is enabled). It's goal is to improve the performance > on systems without the cgroupfs mounted/memory controller enabled or > on the systems with only the root memory cgroup. > > To make things more obvious and avoid potential bugs, let's rename > memcg_kmem_enabled() to memcg_kmem_online(). > > Signed-off-by: Roman Gushchin > Cc: Johannes Weiner > Cc: Michal Hocko > Cc: Shakeel Butt > Cc: Muchun Song > Cc: Dennis Zhou > Cc: linux-mm@kvack.org Makes sense Acked-by: Michal Hocko Thanks! -- Michal Hocko SUSE Labs