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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0798C433EF for ; Tue, 26 Oct 2021 18:11:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 57B2960C4B for ; Tue, 26 Oct 2021 18:11:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 57B2960C4B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id EBD43940008; Tue, 26 Oct 2021 14:11:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E6C37940007; Tue, 26 Oct 2021 14:11:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D3460940008; Tue, 26 Oct 2021 14:11:20 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0102.hostedemail.com [216.40.44.102]) by kanga.kvack.org (Postfix) with ESMTP id C0586940007 for ; Tue, 26 Oct 2021 14:11:20 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 7A351184952EC for ; Tue, 26 Oct 2021 18:11:20 +0000 (UTC) X-FDA: 78739380720.09.E2F52EF Received: from mail-il1-f177.google.com (mail-il1-f177.google.com [209.85.166.177]) by imf11.hostedemail.com (Postfix) with ESMTP id D56E6F0000BE for ; Tue, 26 Oct 2021 18:11:19 +0000 (UTC) Received: by mail-il1-f177.google.com with SMTP id l7so166001iln.8 for ; Tue, 26 Oct 2021 11:11:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=Ec0ioldJ1MBK4OIaEodzymVJ5K5JCkhpNEzS0/+6PX8=; b=XENdqGEOI6q/3fTuCm1zORtXhArpH26Og19ebJ3o0efUBrBil9QnMWHr6RsFUMQXoG Ik/7XiVDMxBMnNFacFpI/9OqPplMtgo0KQXhADaZpkyaUCpwpJSNBmDkp5MHASD37jeZ YTOcehkIllzDGzkRAwoiIlVBbZ9JahIrAS5bZ+YI5kvFQ3RppxwOhHXUaehovNOtZKUE fBpZLw3qbczqBYD0gK8VziXzoXzBpM0lQzmV7ulpaqLyA+2G9kwzW/CDJu47L2AcNzU0 ovWQWPO1Zd2xj/jmkuR7jmV0i3hhtDFbk/fXZKFx7LDVNUAJn00Q962bsC3KRK4OLmwY nL9g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Ec0ioldJ1MBK4OIaEodzymVJ5K5JCkhpNEzS0/+6PX8=; b=JYP9aFeVmclu8usdwgY3Oy6TjDHi5tX+uW3oG5TsdigBcb5rHBO0PYyzVtGe5DEyeU liOmrhA7qvFPszV/VcsjfmtHgzDiEbxzKbh60DPrpJ1bP/0wCJXxZGNsM18ooPCHqAqd Nadj5CT9QEst21Q/KdFFyXqwogFiOA4PviTwi6Z3TtBMtMAW9eFMIIeWbHJHdnukAS4N uBnb+YmkQl/Wk8+jStaHb3gHwQ+YMVT6QqbrZSQzpemBJWCEA2HDCNseL/9r/oihn1bE seyyiIZilBqVv6L58xgJvBWWpGsuAKR3fYWAg6JFzgdphd/SRPB8jttVad36d5cC7zNM CX+A== X-Gm-Message-State: AOAM532v7fnHCACSMTBC0YCBms8JZE/Qk8w6Z9yI6NzjHHUPrX+pkEG+ pxGpYRNHodGpNsVfGSwZebViPQ== X-Google-Smtp-Source: ABdhPJyBBRZz81aeo9jQ0KExdvISBeYDtg0EGuoaiipzzQglxYC3kuSjoUIy9vVK3zvin+lcCvoTpA== X-Received: by 2002:a05:6e02:18cf:: with SMTP id s15mr10944331ilu.198.1635271879075; Tue, 26 Oct 2021 11:11:19 -0700 (PDT) Received: from [192.168.1.30] ([207.135.234.126]) by smtp.gmail.com with ESMTPSA id g13sm10272017ilc.54.2021.10.26.11.11.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 26 Oct 2021 11:11:18 -0700 (PDT) Subject: Re: [PATCH] mm: move more expensive part of XA setup out of mapping check To: Matthew Wilcox Cc: Andrew Morton , Linux Memory Management List , LKML References: <49f67983-b802-8929-edab-d807f745c9ca@kernel.dk> From: Jens Axboe Message-ID: <6a9e41c1-0608-1ba8-788e-8aa402d8a0cb@kernel.dk> Date: Tue, 26 Oct 2021 12:11:18 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: D56E6F0000BE X-Stat-Signature: 4so6c9ph1oqot93igr63kru8fjyadk7m Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=kernel-dk.20210112.gappssmtp.com header.s=20210112 header.b=XENdqGEO; dmarc=none; spf=pass (imf11.hostedemail.com: domain of axboe@kernel.dk designates 209.85.166.177 as permitted sender) smtp.mailfrom=axboe@kernel.dk X-HE-Tag: 1635271879-816832 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 10/26/21 12:08 PM, Matthew Wilcox wrote: > On Tue, Oct 26, 2021 at 10:01:20AM -0600, Jens Axboe wrote: >> The fast path here is not needing any writeback, yet we spend time setting >> up the xarray lookup data upfront. Move the part that actually needs to >> iterate the address space mapping into a separate helper, saving ~30% of >> the time here. > > No objection to this patch, but it did remind me that I never saw an answer to > https://lore.kernel.org/all/CAHk-=wg_-EwefQ_3Osz4iJxTrTk3tfrV53Z7-jaGg=tm9i5TXg@mail.gmail.com/ > (and nor did lore) Totally missed that, and yes there could be cases where that lookup is going to be way too slow. I'll take a look. -- Jens Axboe