From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-223322-1521650408-2-7737090987273345211 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES enroaf, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='198.145.29.99', Host='mail.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: SRS0=x95D=GL=gmail.com=htejun@kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1521650407; b=rEf+YP4ZRLuLrszpsRAIbDOdypGdNpT40iC6foSHJxsfYl8 hizUgKzi11nUDNDaJ21HJdYhe2IKTgCfAes02mMDu4NzK1CRmj4Hvgc+Ira5NIS2 sxno1/EGFUmdeZi7z3Ahf8nrQJgY7bqu3bDv03tZ7izhHryZAzPOv7KGgkFZgY4e +5wTXpYniNfKrUGbsZzUqTOy+MqjTgS14u0u7PsEjtpPYkb/CawAlagj8bR160cU 3uxW06/YTRpDCILPodrxfQ/aQOCCQhyGuD57G/AzDR120DcmpRIqedkvikdmxWir S/2LFyfu5QAj+DCrXDQH+khFe2/wwGXYIKMOFPQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=sender:date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to; s=arctest; t= 1521650407; bh=xYJgaS3cN6r2RtiwSDEF1CrVvL6RHq78gv+tMKIYbHI=; b=u g/Hf+mL95xrPgNL1dWGt+Vb4OxfpJfs5drgLQGuIcYLRb0ud0h3VaoFJ7dL1dIuK 2cULUIbBmOfd+MSor774pWK+IRcDA8RjC0hIKh+dupehEgcwFnlNZBLFdXTBFn0Y bE5L2VZ9adzzuvdF51sSUtvzLWA6Xw+/4DWogrUPo5RZSTFbE2sG5WUQ+vi1Unhg CIZfT+dAyekqXJUetfmodRHEyXHblshyVEg/YnWAXfV7QjH83aymRM7c/OVEUN8q +G83TnB/kn8/S9XQ4JbSNB5lqQIABj4PAEkPOZxfh9npnp0WvoAK94mMdAbh9aoD wAePKuC9qcdIxrTwMIcWA== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=gmail.com header.i=@gmail.com header.b=FjSIZm8f x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20161025; dmarc=none (p=none,d=none) header.from=kernel.org; iprev=pass policy.iprev=198.145.29.99 (mail.kernel.org); spf=none smtp.mailfrom="SRS0=x95D=GL=gmail.com=htejun@kernel.org" smtp.helo=mail.kernel.org; x-aligned-from=domain_pass (Domain match); x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=gwyefMku; x-ptr=pass x-ptr-helo=mail.kernel.org x-ptr-lookup=mail.kernel.org; x-return-mx=pass smtp.domain=kernel.org smtp.result=pass smtp_is_org_domain=yes header.domain=kernel.org header.result=pass header_is_org_domain=yes; x-tls=pass version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128; x-vs=clean score=-100 state=0 Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=gmail.com header.i=@gmail.com header.b=FjSIZm8f x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20161025; dmarc=none (p=none,d=none) header.from=kernel.org; iprev=pass policy.iprev=198.145.29.99 (mail.kernel.org); spf=none smtp.mailfrom="SRS0=x95D=GL=gmail.com=htejun@kernel.org" smtp.helo=mail.kernel.org; x-aligned-from=domain_pass (Domain match); x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=gwyefMku; x-ptr=pass x-ptr-helo=mail.kernel.org x-ptr-lookup=mail.kernel.org; x-return-mx=pass smtp.domain=kernel.org smtp.result=pass smtp_is_org_domain=yes header.domain=kernel.org header.result=pass header_is_org_domain=yes; x-tls=pass version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-Remote-Delivered-To: security@kernel.org DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CDF11217D9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=htejun@gmail.com X-Google-Smtp-Source: AG47ELsLSigFnRgzQrEg7i3t5zOS7Y42yIqs/gmKszaXUayy13li48GYzE8NqwRoV1sQJAM9RWKGFw== Sender: Tejun Heo Date: Wed, 21 Mar 2018 09:40:00 -0700 From: Tejun Heo To: Oleg Nesterov Cc: torvalds@linux-foundation.org, jannh@google.com, paulmck@linux.vnet.ibm.com, bcrl@kvack.org, viro@zeniv.linux.org.uk, kent.overstreet@gmail.com, security@kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 8/8] fs/aio: Use rcu_work instead of explicit rcu and work item Message-ID: <20180321164000.GC2149215@devbig577.frc2.facebook.com> References: <20180314194205.1651587-1-tj@kernel.org> <20180314194515.1661824-1-tj@kernel.org> <20180314194515.1661824-8-tj@kernel.org> <20180321155812.GA9382@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180321155812.GA9382@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Hey, Oleg. On Wed, Mar 21, 2018 at 04:58:13PM +0100, Oleg Nesterov wrote: > > - struct rcu_head free_rcu; > > - struct work_struct free_work; /* see free_ioctx() */ > > + struct rcu_work free_rwork; /* see free_ioctx() */ > > IIUC, you can't easily share rcu_work's, thus every kioctx needs its own > ->free_rwork and this looks sub-optimal. > > What do you think about the (untested) patch below? > > Oleg. > > > --- a/fs/aio.c > +++ b/fs/aio.c > @@ -115,8 +115,10 @@ struct kioctx { > struct page **ring_pages; > long nr_pages; > > - struct rcu_head free_rcu; > - struct work_struct free_work; /* see free_ioctx() */ > + union { > + struct rcu_head free_rcu; > + struct llist_node free_llist; > + }; It really depends on how much we want to optimize. Do you think it matters enough? Thanks. -- tejun