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=unavailable 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 37FDDC43381 for ; Fri, 15 Feb 2019 17:16:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04A2D2190C for ; Fri, 15 Feb 2019 17:16:26 +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" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727559AbfBORQV (ORCPT ); Fri, 15 Feb 2019 12:16:21 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:39692 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726028AbfBORQU (ORCPT ); Fri, 15 Feb 2019 12:16:20 -0500 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) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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.