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 5095FC35FFF for ; Thu, 20 Mar 2025 15:16:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2F24A280002; Thu, 20 Mar 2025 11:16:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2A186280001; Thu, 20 Mar 2025 11:16:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 16951280002; Thu, 20 Mar 2025 11:16:21 -0400 (EDT) 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 EC8C4280001 for ; Thu, 20 Mar 2025 11:16:20 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id B04008160B for ; Thu, 20 Mar 2025 15:16:20 +0000 (UTC) X-FDA: 83242280520.21.8794EDE Received: from out-182.mta1.migadu.com (out-182.mta1.migadu.com [95.215.58.182]) by imf25.hostedemail.com (Postfix) with ESMTP id 085A1A001A for ; Thu, 20 Mar 2025 15:16:17 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=pD7NpAzN; spf=pass (imf25.hostedemail.com: domain of roman.gushchin@linux.dev designates 95.215.58.182 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1742483778; 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=gZZRLALnFywosQyAbfYxHqxa+mApnY/ujk8b1UZoQbg=; b=5pEnF9kuEmGbCE1V2bgPizeeiOhikWUCOlNwYdmRhNEK5cg/tqOqhFLB0frZl32UjlVN/P ydlc3cfj1+1ElySkPLC5LW/WWnyFTB9ErGZD866B7ExaUTA4L3ryTbpMXbQd+EvSU0JxEB o0s965s7ClRXg5nG7sRGSOr1LIh2hO4= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=pD7NpAzN; spf=pass (imf25.hostedemail.com: domain of roman.gushchin@linux.dev designates 95.215.58.182 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1742483778; a=rsa-sha256; cv=none; b=rhsNEagTCq/VaqXn7AqRGhrLweX79Ctc6rFkFluGVLjYmPknOBTXRrJY6HyE3UOiteHTE5 Uh70aUn7CXCazZrkNkkoYA7sTUzD/3v9HLPnyUFKVt4EXv3P+pUxKHJywQMRhPaUkE0sKC aw33CUqof6/oDqU5qjceeB7NWgTWfbg= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1742483775; 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: in-reply-to:in-reply-to:references:references; bh=gZZRLALnFywosQyAbfYxHqxa+mApnY/ujk8b1UZoQbg=; b=pD7NpAzNuRwuLWgqSWOU8Zf1FkMoKvIyDExeNDjj8bm2eJvdnfzt2YjmX+w1iFIRGENLOG kMmUvfKYuxJDtso+P8cbqEr9t9de543EW9597nKbdN3IxsD1cJ8p7HvbkkJENtRejOGZdQ eGPVw+4P8l8ocOJepro6emUD+/v42kE= From: Roman Gushchin To: Johannes Weiner Cc: Shakeel Butt , Jingxiang Zeng , akpm@linux-foundation.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, mhocko@kernel.org, muchun.song@linux.dev, kasong@tencent.com Subject: Re: [RFC 2/5] memcontrol: add boot option to enable memsw account on dfl In-Reply-To: <20250320142846.GG1876369@cmpxchg.org> (Johannes Weiner's message of "Thu, 20 Mar 2025 10:28:46 -0400") References: <20250319064148.774406-1-jingxiangzeng.cas@gmail.com> <20250319064148.774406-3-jingxiangzeng.cas@gmail.com> <7ia4tt7ovekj.fsf@castle.c.googlers.com> <20250320142846.GG1876369@cmpxchg.org> Date: Thu, 20 Mar 2025 15:16:10 +0000 Message-ID: <7ia4plibspfp.fsf@castle.c.googlers.com> MIME-Version: 1.0 Content-Type: text/plain X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Queue-Id: 085A1A001A X-Rspamd-Server: rspam03 X-Stat-Signature: 8hd64ab6p49esehz6bk43cbycebwkpgd X-HE-Tag: 1742483777-446979 X-HE-Meta: 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 sd1zp6TM rkJR45vOQbuoKeaN0vcRavRIkUSm4X3w+FBD9G3QApvTDnFzlDBaT7mJlV/iwECuEXKGly95qsXLeoxB2I/j0+DXM7/GPBYur0sPjA5pXLYE2k1oNfl3yp64IRKZck3rT7X5VjarknxpNB47D2FA69UXhMn/d/HfDBi2NNKZ2/CO0Gjk= 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: List-Subscribe: List-Unsubscribe: Johannes Weiner writes: > On Wed, Mar 19, 2025 at 10:30:20PM +0000, Roman Gushchin wrote: >> Shakeel Butt writes: >> >> > On Wed, Mar 19, 2025 at 02:41:45PM +0800, Jingxiang Zeng wrote: >> >> From: Zeng Jingxiang >> >> >> >> Added cgroup.memsw_account_on_dfl startup parameter, which >> >> is off by default. When enabled in cgroupv2 mode, the memory >> >> accounting mode of swap will be reverted to cgroupv1 mode. >> >> >> >> Signed-off-by: Zeng Jingxiang >> >> --- >> >> include/linux/memcontrol.h | 4 +++- >> >> mm/memcontrol.c | 11 +++++++++++ >> >> 2 files changed, 14 insertions(+), 1 deletion(-) >> >> >> >> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h >> >> index dcb087ee6e8d..96f2fad1c351 100644 >> >> --- a/include/linux/memcontrol.h >> >> +++ b/include/linux/memcontrol.h >> >> @@ -62,10 +62,12 @@ struct mem_cgroup_reclaim_cookie { >> >> >> >> #ifdef CONFIG_MEMCG >> >> >> >> +DECLARE_STATIC_KEY_FALSE(memsw_account_on_dfl); >> >> /* Whether enable memory+swap account in cgroupv2 */ >> >> static inline bool do_memsw_account_on_dfl(void) >> >> { >> >> - return IS_ENABLED(CONFIG_MEMSW_ACCOUNT_ON_DFL); >> >> + return IS_ENABLED(CONFIG_MEMSW_ACCOUNT_ON_DFL) >> >> + || static_branch_unlikely(&memsw_account_on_dfl); >> > >> > Why || in above condition? Shouldn't it be && ? >> > >> >> } >> >> >> >> #define MEM_CGROUP_ID_SHIFT 16 >> >> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >> >> index 768d6b15dbfa..c1171fb2bfd6 100644 >> >> --- a/mm/memcontrol.c >> >> +++ b/mm/memcontrol.c >> >> @@ -5478,3 +5478,14 @@ static int __init mem_cgroup_swap_init(void) >> >> subsys_initcall(mem_cgroup_swap_init); >> >> >> >> #endif /* CONFIG_SWAP */ >> >> + >> >> +DEFINE_STATIC_KEY_FALSE(memsw_account_on_dfl); >> >> +static int __init memsw_account_on_dfl_setup(char *s) >> >> +{ >> >> + if (!strcmp(s, "1")) >> >> + static_branch_enable(&memsw_account_on_dfl); >> >> + else if (!strcmp(s, "0")) >> >> + static_branch_disable(&memsw_account_on_dfl); >> >> + return 1; >> >> +} >> >> +__setup("cgroup.memsw_account_on_dfl=", memsw_account_on_dfl_setup); >> > >> > Please keep the above in memcontrol-v1.c >> >> Hm, I'm not sure about this. This feature might be actually useful with >> cgroup v2, as some companies are dependent on the old cgroup v1 >> semantics here but otherwise would prefer to move to v2. >> In other words, I see it as a cgroup v2 feature, not as a cgroup v1. >> So there is no reason to move it into the cgroup v1 code. > > Agreed. Let's think of this proposal as making memsw tracking and > control a full-fledged v2 feature. > >> I think it deserves a separate config option (if we're really concerned >> about the memory overhead in struct mem_cgroup) or IMO better a >> boot/mount time option. > > Yeah, a config option forces distros to enable it :/ > > I'm hesitant to agree with making it optional in any manner. If you > consider the functionality that is implemented, the overhead should be > fairly minimal. It isn't right now, because page_counter contains a > ton of stuff that isn't applicable to this new user. That overhead is > still paid for unnecessarily by users who _do_ need to enable it. Agree. Memcg is already huge, so another page_counter won't add a lot percentage-wise. > > It seems like a good opportunity to refactor struct page_counter. I don't think it's a hard dependency here, but otherwise fully agree. Thanks!