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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7E017C10F02 for ; Fri, 15 Feb 2019 17:16:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 38B372190C for ; Fri, 15 Feb 2019 17:16:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="MCF5Gbp2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 38B372190C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AD0438E0003; Fri, 15 Feb 2019 12:16:22 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A5A728E0001; Fri, 15 Feb 2019 12:16:22 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 948C98E0003; Fri, 15 Feb 2019 12:16:22 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-pl1-f199.google.com (mail-pl1-f199.google.com [209.85.214.199]) by kanga.kvack.org (Postfix) with ESMTP id 51BA78E0001 for ; Fri, 15 Feb 2019 12:16:22 -0500 (EST) Received: by mail-pl1-f199.google.com with SMTP id cg18so7326422plb.1 for ; Fri, 15 Feb 2019 09:16:22 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:date:from:to:cc:subject :message-id:references:mime-version:content-disposition:in-reply-to :user-agent; bh=ooGmETeAMfU5WngSU05Ee1Ynx92AHDeGIIebdL4CHw0=; b=WbgQ3yEeOb2bEo+8aM5nPBdSgvFBhbDw5kcGnUdsaupr8ZC+R/rUQ3XYIhx1Y2yLPI 3MostISwEAz2GwVtJxFT44wE3Jy3n0ENKvmNP7J976Uzo4ztSMq6BAyGaSLnVteMMijA 9/f/Pn1iT8DAqHtIdZkI6NaoSJkISx6qMyh4K3WNpj4SMTwTPYC0lpnCz50hWuhtF5Q/ hVEr5Le3yU5aaaNrHPOY+I1MVHbARwXrEAnQO9Yu7dj3IOmAIGH+aQRY4jg9hJCNowDn o/G5kDje7zlU9N7rHWXfQpnj+UhpzaG4HOALHeBf8mCBTyS7qzAfgm9SLTupP1dI692t wz0w== X-Gm-Message-State: AHQUAuZmw8c3Vb60kReaIANn/MMntSbRMH6B1mmHxE67pcyrMTa2ChgY ou4yT1cwMUVVwT3HvRMF0GKjIxnE1QE1+mSyZCK2u9Ug1SGEV6Puhuyk4jD88V3FXWE00ZU6/UX +wrAwIJoTqvZrYRqskeQw4D38v87BypxsAYSwsWDDhVz21IRC3Xy1SUl7uW5XPXB36g== X-Received: by 2002:a63:2c7:: with SMTP id 190mr9655081pgc.367.1550250981947; Fri, 15 Feb 2019 09:16:21 -0800 (PST) X-Google-Smtp-Source: AHgI3IY4QT3pYZIaCPTqTuKPrfsx0hv/jiD+AZJyQ/wXt/j/c9UfSu6LMAy9q/sNoLBm1eguS225 X-Received: by 2002:a63:2c7:: with SMTP id 190mr9655037pgc.367.1550250981276; Fri, 15 Feb 2019 09:16:21 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1550250981; cv=none; d=google.com; s=arc-20160816; b=kjsQ07L2MdDJiJPECc4kTzhLtj8iu1kZCGY72RTI55kIdmRJDB9gHqIFbyLtnBpthF tcj8NW2YG82TbV/1JCsYIIjtYA9ZCqqReMjqEG7k3pyT50V+sidYQXgrPnNft1sRBkoK 6YwhWbEacbOK9AlMDAJhty6qixkDen3r8Pl10me856ERzVW3usiSt6iUYNKYiv2PYnff Jd8uizXU8/M4xDwIojrYQFY3ZVmFotd5jBD9er6hPqbg4zsHsweb6XmT2qZ2IEtgnb79 4ywAY4iaLM0hWM5B9CosbomCiZf991/mryr8CQPZYdRdrAasU9kWNp3La4G2iK2ZsMye kISg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature; bh=ooGmETeAMfU5WngSU05Ee1Ynx92AHDeGIIebdL4CHw0=; b=LzdjQzJjj6w2d7AEwFMVDYA+hJI1JeZ+muf4+AANUohFKZaMLZDJuJ/VmJKMQCCvQ3 YyEwZ+/62WZCakl+JX2PlTwyscf/9bhTtz7OaMw1CAhH8hE3S3pPQ68dPaNT4S7sCeG+ CXqydga84osOZK/1FI5KAT/DhrSD+25h6txFiV4lpMsxS7oZjPcfkY10k4bvv5Fc3aeS 0A3kaCbrKOWSbkqCwVsB6hh9fVOBcEIx06RnhfvCkE8Q+7F1SmWbqqgdo58h4QPrTtZe auQFdHE6Ffnk8xzMsnpojBhOjtKE9KGWxHe3kvfa2AZk7FRLhUz+47+eJuQoswrwMHzY KSRQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=MCF5Gbp2; spf=pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=willy@infradead.org Received: from bombadil.infradead.org (bombadil.infradead.org. [2607:7c80:54:e::133]) by mx.google.com with ESMTPS id s66si6022964pgs.115.2019.02.15.09.16.21 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 15 Feb 2019 09:16:21 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=MCF5Gbp2; spf=pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=willy@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=ooGmETeAMfU5WngSU05Ee1Ynx92AHDeGIIebdL4CHw0=; b=MCF5Gbp2jwQST1+kskq7BCogZ yLJ04gp3VEiMQK5dNfjFJzV5Il16yADz8CfgwZlbi4tFduPzcyOpCByjun9FojEiNArJiTjErZdXQ gH5HF3YWG5E/2GT7PnyXmTjuLz26bF+GIOsZ9kv84p+RQsZSe4BW0o7YAcilSiMJGjjxIsQDge9cz fmd4rAxHh9FZFxzpB85JSvHZVbc0fQOutDIHDrbXHIV9Tq853kzjgrLNK6zQXOND1xAvTseyLAB7R XyZfjNEV3pCHZrncBG2pqy7TNEPcOuM5GBw2cmKlw/9x5DMSDM+OFMuhAKBeTez27HuK8p5g+iNuw +DZVLTgng==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1guh63-0004um-DE; Fri, 15 Feb 2019 17:16:19 +0000 Date: Fri, 15 Feb 2019 09:16:19 -0800 From: Matthew Wilcox To: Dave Watson Cc: "lsf-pc@lists.linux-foundation.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , Maged Michael , "linux-kernel@vger.kernel.org" Subject: Re: [LSF/MM TOPIC] Improve performance of fget/fput Message-ID: <20190215171619.GI12668@bombadil.infradead.org> References: <20190215163852.6ls6bchssazma6bm@davejwatson-mba.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190215163852.6ls6bchssazma6bm@davejwatson-mba.local> User-Agent: Mutt/1.9.2 (2017-12-15) 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 Fri, Feb 15, 2019 at 04:38:05PM +0000, Dave Watson wrote: > There might also be ways to rearrange the file* struct or fd table so > that we're not taking so many cache misses for sockfd_lookup_light, > since for sockets we don't use most of the file* struct at all. I don't think there's too much opportunity to rearrange the fd table. We go from task_struct->files_struct->fdtable->fd[i]. I have a plan to use the Maple Tree data structure I'm currently working on to change that to task_struct->files_struct->maple_node->fd[i], but it'll be the same number of cache misses.