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 CAEE6D11707 for ; Fri, 25 Oct 2024 06:57:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6114F6B008A; Fri, 25 Oct 2024 02:57:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 59B1C6B008C; Fri, 25 Oct 2024 02:57:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3EBFB6B0092; Fri, 25 Oct 2024 02:57:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 1998C6B008A for ; Fri, 25 Oct 2024 02:57:36 -0400 (EDT) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 259FC1A059A for ; Fri, 25 Oct 2024 06:57:01 +0000 (UTC) X-FDA: 82711218408.05.1140768 Received: from mail-wr1-f42.google.com (mail-wr1-f42.google.com [209.85.221.42]) by imf30.hostedemail.com (Postfix) with ESMTP id 1434A8000E for ; Fri, 25 Oct 2024 06:56:56 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=LHrlBCrB; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf30.hostedemail.com: domain of mhocko@suse.com designates 209.85.221.42 as permitted sender) smtp.mailfrom=mhocko@suse.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1729839414; a=rsa-sha256; cv=none; b=PyS/IXPIjNoZ/72HEU0MyRgFlWNNC9qmG7Dt2eeSDyrXByeaVUD3Uulaz4AxQqtNqJgAIn RpBkzIs3kAxnnrecTffMytmigE7VP4VcqL91qM7QkLuX0HUrmgtbp2BAYDJnaJYqtJZVPP 42aTDMr8fsKpf07Y18V5RFLRamwQAEI= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=LHrlBCrB; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf30.hostedemail.com: domain of mhocko@suse.com designates 209.85.221.42 as permitted sender) smtp.mailfrom=mhocko@suse.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1729839414; 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=uIGhUUrvEJvBYTpVTQCf7vDRTHIN44D2R4RlMBTCdG4=; b=6OQbWs/VB5+Kgh43nbNa+AoPNeTjo0EG3i8d1iY9VdC3JZGRiqCai7QlkxqiFD1APT1k1h LJoe+dclAS4go+BvF8J3x10h78xgefbVg0HeAK+o3I3fjb4K8Otnj1MlkTgUp/5ROpxUek 9AdZDp5Ve6XZ5JbdV0IaJUXXkScb6Ro= Received: by mail-wr1-f42.google.com with SMTP id ffacd0b85a97d-37d4c482844so1088919f8f.0 for ; Thu, 24 Oct 2024 23:57:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1729839452; x=1730444252; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=uIGhUUrvEJvBYTpVTQCf7vDRTHIN44D2R4RlMBTCdG4=; b=LHrlBCrBAdRfkaPzbK59XbOEfL/CxiZdxjHUKp4ANWmDFbSx0f+iokQINjFV5eacyA pw/OGvcwjJE9dlkjOdEwHIhz0LcKEvrZKaRgWrx19JQ7iEuAV8Qekhh7fwY+sYO+EKWy LyeHOXWCuty+00BQqNG6kOugx/bKYia2qcIlLNq3MCWHOjFC39B/6H+5H8cRfXS3ata5 3aqXHq0f+OkQmUnnxL6n6UKcMmYG6in1zXUrhOJl+++4yTmjKognIcpptg/eJDSsKoz4 sPGJmGqe88A7cSYjRWGs03Efsy12/4VpK3fysAMuS7YG+aAMN8aEe6PlOQ/55yzed6Mx W/Pg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1729839452; x=1730444252; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=uIGhUUrvEJvBYTpVTQCf7vDRTHIN44D2R4RlMBTCdG4=; b=lVvXKFvOW54ocDetL+UADe4mscFr4C+1d+JMMbwJrutZLLgDXXfRldUzMxR6OAzfWk AQ3UITwfoaR3N5yyc1mpVUwMhmvD80+qGIafsH36iPc8/QJeaCTmSTU3esWRQD8bDN4p rnBUoekxBLr5/57tvr6uCOYxAB+WbIPZCy3O7jAXZPwCFHcYqRRkcAeNu3AQwLmsswod heXScxn1c4yL1+FhO4PfPjl3SbCDC8oM0muGs718Rszpplr9GDlQFtAnXSF2TXq8VBFJ yZswkjXniF9Yl8fgYbzCo8DhBRoRca4K2KOMXgC9NZtEtp+0i8JLW9/6M6aIFaqwGDYx DWUg== X-Forwarded-Encrypted: i=1; AJvYcCWQIJDDixkVsdTlqCfvpOSOk6Mp2x77fUETSGYI91AKpHRzw9aRqC9BswFe32wtmH23h0EqHE98hw==@kvack.org X-Gm-Message-State: AOJu0YyIXIPOvc2Dn2sLQsHE9G1GnBgFkare34KuP015bDoTeXDHzY0z 1sUzs4UCX0s7CKdRIkbQRi92/4c2RZrIH/rgwmirP3BoCOXPwlKDBIzBIEObqQk= X-Google-Smtp-Source: AGHT+IG5jRpCojmvKmj5tkta0HqMtVq7AqWJFDLy+BIjGm7NrH0ck5YQqqlaOo1BUh5vNwWV8SPF5w== X-Received: by 2002:adf:e808:0:b0:37d:4ebe:164b with SMTP id ffacd0b85a97d-380458ec1camr2763416f8f.44.1729839452483; Thu, 24 Oct 2024 23:57:32 -0700 (PDT) Received: from localhost (109-81-81-105.rct.o2.cz. [109.81.81.105]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38058b70f25sm749911f8f.67.2024.10.24.23.57.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Oct 2024 23:57:32 -0700 (PDT) Date: Fri, 25 Oct 2024 08:57:31 +0200 From: Michal Hocko To: Shakeel Butt Cc: Andrew Morton , Johannes Weiner , Roman Gushchin , Muchun Song , Hugh Dickins , Yosry Ahmed , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, Meta kernel team Subject: Re: [PATCH v1 4/6] memcg-v1: no need for memcg locking for writeback tracking Message-ID: References: <20241025012304.2473312-1-shakeel.butt@linux.dev> <20241025012304.2473312-5-shakeel.butt@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241025012304.2473312-5-shakeel.butt@linux.dev> X-Rspam-User: X-Stat-Signature: 4o6d3a31mr3w8q9p4yrfr6e5aonuf5id X-Rspamd-Queue-Id: 1434A8000E X-Rspamd-Server: rspam02 X-HE-Tag: 1729839416-80017 X-HE-Meta: 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 GjHO9lzV ri8Bq5iO8Vipwd8K3McSomPbC3CpGtTqvtpATkjDwUeCNFXqRL3phpPd1odTfQQcb3OPu8SuwqbGegrDAngGsQOpaSjPVIF2STHyS8MG93qTWTNb6U6z6xiHmf9E424tcn+P/vf3FIczNuF5MN4zqxzqZwv1YoL2+5/vZMXpiQS16Mkjd5XQxw4e/AJxGxHo1NsAG2Hqabl7EIDSCCZgWnvoukpRcZRZsU/BlQIfoSc79pl3moX4lRIF//7puJDltXY9piT3oNdBcNHgKcflXdPYOjjFB+Hi3XvwAEenHkELD3hM/Mw9VDimxNg+bBohLheYAOh3YyygwysvVfH0JghTbD234G0sslTc0rgIQMkvOCPmAfqa9MncmNg== 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: On Thu 24-10-24 18:23:01, Shakeel Butt wrote: > During the era of memcg charge migration, the kernel has to be make sure > that the writeback stat updates do not race with the charge migration. > Otherwise it might update the writeback stats of the wrong memcg. Now > with the memcg charge migration deprecated, there is no more race for s@deprecated@gone > writeback stat updates and the previous locking can be removed. > > Signed-off-by: Shakeel Butt Acked-by: Michal Hocko Thanks! > --- > mm/page-writeback.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index a76a73529fd9..9c3317c3a615 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -3083,7 +3083,6 @@ bool __folio_end_writeback(struct folio *folio) > struct address_space *mapping = folio_mapping(folio); > bool ret; > > - folio_memcg_lock(folio); > if (mapping && mapping_use_writeback_tags(mapping)) { > struct inode *inode = mapping->host; > struct backing_dev_info *bdi = inode_to_bdi(inode); > @@ -3114,7 +3113,6 @@ bool __folio_end_writeback(struct folio *folio) > lruvec_stat_mod_folio(folio, NR_WRITEBACK, -nr); > zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, -nr); > node_stat_mod_folio(folio, NR_WRITTEN, nr); > - folio_memcg_unlock(folio); > > return ret; > } > @@ -3127,7 +3125,6 @@ void __folio_start_writeback(struct folio *folio, bool keep_write) > > VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio); > > - folio_memcg_lock(folio); > if (mapping && mapping_use_writeback_tags(mapping)) { > XA_STATE(xas, &mapping->i_pages, folio_index(folio)); > struct inode *inode = mapping->host; > @@ -3168,7 +3165,6 @@ void __folio_start_writeback(struct folio *folio, bool keep_write) > > lruvec_stat_mod_folio(folio, NR_WRITEBACK, nr); > zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, nr); > - folio_memcg_unlock(folio); > > access_ret = arch_make_folio_accessible(folio); > /* > -- > 2.43.5 -- Michal Hocko SUSE Labs