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 378DBD6552F for ; Tue, 26 Nov 2024 17:26:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BD5956B0082; Tue, 26 Nov 2024 12:26:22 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B855B6B0085; Tue, 26 Nov 2024 12:26:22 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A4D296B009F; Tue, 26 Nov 2024 12:26:22 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 854456B0082 for ; Tue, 26 Nov 2024 12:26:22 -0500 (EST) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 0F863C07B6 for ; Tue, 26 Nov 2024 17:26:22 +0000 (UTC) X-FDA: 82828924878.04.32BA64E Received: from mail-lf1-f43.google.com (mail-lf1-f43.google.com [209.85.167.43]) by imf10.hostedemail.com (Postfix) with ESMTP id E17B7C0003 for ; Tue, 26 Nov 2024 17:26:17 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=fXvzooP7; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf10.hostedemail.com: domain of anders.blomdell@gmail.com designates 209.85.167.43 as permitted sender) smtp.mailfrom=anders.blomdell@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1732641976; a=rsa-sha256; cv=none; b=r2P8e3QUYzd3h9MHrdSIQVdqrzWchKQzsDMuNhNpXow+rPcTrarhztmZitrxvFH3xflDvP Cpzr1/rFhmdb8hvDei0kHG/N+jFY0S/qDose4Zu00wK1sB0ANEn/J80Wun1fziXh6fmj5t dAf1AfV7EEWhWgA9C5o17+QfNu5TNdg= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=fXvzooP7; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf10.hostedemail.com: domain of anders.blomdell@gmail.com designates 209.85.167.43 as permitted sender) smtp.mailfrom=anders.blomdell@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1732641976; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=mbotIOfnAlUpiXN0cwY6JBmQStHByFNUpy3SVfR48QQ=; b=edLeK9ObsSaZ9mxT2oHQYiRoKWhQZZ3MaobG7h2mw8yomMgl57Q7MDxxLghsXcpJKM8h7x QcNOMXDbxDweRq3QvGnI8hXRgVaWrdS/Y7zW2ycIrYK8o0AeMsmUxZaNUHPBUl2KqoqGHc /pkG/cXwP554t/GT/CXVbQFFTZYZzSE= Received: by mail-lf1-f43.google.com with SMTP id 2adb3069b0e04-53dee56edceso751732e87.1 for ; Tue, 26 Nov 2024 09:26:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1732641978; x=1733246778; darn=kvack.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=mbotIOfnAlUpiXN0cwY6JBmQStHByFNUpy3SVfR48QQ=; b=fXvzooP7dWrvqtpCCZvcQ69KAVTh7cenkGzZXkr40MDlqN1X09uchpAA0c5v//5tMF NA7AJmbxHqFlvc3ZxuWsGAJlVEEi0xXaCsKUoC+ZrA1rNqoILHIMKieoD/iwginePm6C UueUhRaYh8I+qssj9EvHmHsHLWPBCQM5pp78+QPaUfK3C1wHknOHphrCYbR0DHsLdBdI ByawSlmLaf+ioudO7JcbaSOOK6BQKlsJ9sJHSjDxO1X1sYVDwUe0s5rHK1glV3NQVClS m2zPa8hLWC1Cs7M7OUsiLxDjUvutKPDVHOKhAjox00o5+eq+mpEP4d+XFdDF1rHZuhgB Fu1g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1732641978; x=1733246778; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=mbotIOfnAlUpiXN0cwY6JBmQStHByFNUpy3SVfR48QQ=; b=jkDczCgz5MqkaGq5+VP5GQVzIwAq79CeeWojZ3bKn6wcyJWRcnRdqCHVN16RYvG1gS EDD5rbnLgNmBixTFptpJLkpR1KzDDA8jiXESwXHCWX3xuHrdLmn2lfrN4alr6NkKDee3 1wh7LWLzZhnCo447N9rKbxidNxW5aqYh9+3bQUSdV7Z4D2A2IwtZi6VmR5O7Vs61Stzj cS4rxjMHDGnGlia+QikKuUK81ux+LlJHcd921Fw2WKZeGKNRoT6T7GE+YuFLPjE3N/0G m9f2kNU6niw+ODy/ARktbkLWIuAZcyVcQJd6TEGzHbZwFAVBe8W7olObTaNOepqS80HV 2LYg== X-Forwarded-Encrypted: i=1; AJvYcCVYS6Y+StlWrrpzAFwtTlcCr0g5mmd5siP5zp2yBYpXkbJLz8lz5vs7ZF4zMiFhN/6CX4CsuvqjZA==@kvack.org X-Gm-Message-State: AOJu0Yyd0udvUJD2WRX/wMcXNxWtLI+jTM81FKbU6VQSA/JOt1GsvBTH ZTSvkVWZGBTYWa/W2MXyC27qKP+7EQLa3uHlQ290AWBh8gyIv38R X-Gm-Gg: ASbGncuolWxT9aH0CuHha4+P8wkZjTWQ/Tl4Eva4teIvC69ftU5GLisIlrZaeZerj6m l3xmjHykHdwnVqqmhMbGaWqCjYdppJxKl0ydf60oof+ckcXTIS7qySbsW7PUQswPkA9t02VorBO mYuRXm79M8YNaPPRpVc5vDS6ldT+zbfQYW+HpdHdCwe5PmL7/ZpCDZnAFVRnm3nVDjLZwQJWjqY NIu4IGYyV096hBEzuvfqQn9VlCSLjWSDQAJqG1P1HZ4XHkdW3Dwa+9+DThpkBRlXo1GAlefNcfe DgQLMbBb6ZuIP+wtrD8PWQd3 X-Google-Smtp-Source: AGHT+IEtv4oFJfiSacSbN3zNtp7opyl3x9b+XbgiIuNfyCw+fad4RwfteGd/8dhj4mLs9xnvqQ2raQ== X-Received: by 2002:a05:6512:3052:b0:53d:edf6:96e2 with SMTP id 2adb3069b0e04-53dedf697d4mr903126e87.11.1732641978019; Tue, 26 Nov 2024 09:26:18 -0800 (PST) Received: from ?IPV6:2a00:801:2f0:b124:4cc6:80e8:d57e:220? ([2a00:801:2f0:b124:4cc6:80e8:d57e:220]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-53dd2451a3csm2052062e87.82.2024.11.26.09.26.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 26 Nov 2024 09:26:16 -0800 (PST) Message-ID: <569d0df0-71d5-4227-aa28-e57cd60bc9f1@gmail.com> Date: Tue, 26 Nov 2024 18:26:13 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Regression in NFS probably due to very large amounts of readahead To: Matthew Wilcox Cc: Jan Kara , Philippe Troin , Andrew Morton , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, NeilBrown References: <49648605-d800-4859-be49-624bbe60519d@gmail.com> <3b1d4265b384424688711a9259f98dec44c77848.camel@fifi.org> <4bb8bfe1-5de6-4b5d-af90-ab24848c772b@gmail.com> <20241126103719.bvd2umwarh26pmb3@quack3> <20241126150613.a4b57y2qmolapsuc@quack3> Content-Language: en-US From: Anders Blomdell In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: E17B7C0003 X-Stat-Signature: hdrdqtzrxtya3bd3kqkm14rpkmi6i7gy X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1732641977-946307 X-HE-Meta: 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 Blh7XnG7 3CD2sWWbWmece1lm/+KugmLnC3vleseTeJMEtvf4zkazPSYbQclOMlIZszMb7nCYAcFYccrWbLzHw4NKAU4/DuS1gw9DR33OM7S9xNjH8CIr7dW5ex2OCP7Np6ddFoBLPocGPRuoVhuJiMLFXo8jFC+ClVgvtr6Z7DZ/e9MVb34XO+baN88ufDBt9blH1en2k5+jIbYuKl5O35qSSzv99z5sIZi97h3uxbtegcKWBc9Y4xyDELg0zS1/gDhddK2mdmZBk/n/oMRKhml1bsjKe4X/vmyoYN5wJGyc+D0KnCne7DtN253N4akVJ2ix+HvPFqCWd7gQBojlT6T1QBY8MNfAlxOf5W52R5cad/yyWlRbU9q120WEgPyt1pQkac8uI+EsoBZd4n73zv0oJX2yr/KpilDjY3bpITFH5ShkRFEynG+dV/XOVL6xA+bXpvMfeBLML0vrppNjKNguYlQWt+y3MLKlqcUBt09SE X-Bogosity: Ham, tests=bogofilter, spamicity=0.003989, 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 2024-11-26 17:55, Matthew Wilcox wrote: > On Tue, Nov 26, 2024 at 04:28:04PM +0100, Anders Blomdell wrote: >> On 2024-11-26 16:06, Jan Kara wrote: >>> Hum, checking the history the update of ra->size has been added by Neil two >>> years ago in 9fd472af84ab ("mm: improve cleanup when ->readpages doesn't >>> process all pages"). Neil, the changelog seems as there was some real >>> motivation behind updating of ra->size in read_pages(). What was it? Now I >>> somewhat disagree with reducing ra->size in read_pages() because it seems >>> like a wrong place to do that and if we do need something like that, >>> readahead window sizing logic should rather be changed to take that into >>> account? But it all depends on what was the real rationale behind reducing >>> ra->size in read_pages()... >> >> My (rather limited) understanding of the patch is that it was intended to read those pages >> that didn't get read because the allocation of a bigger folio failed, while not redoing what >> readpages already did; how it was actually going to accomplish that is still unclear to me, >> but I even don't even quite understand the comment... >> >> /* >> * If there were already pages in the page cache, then we may have >> * left some gaps. Let the regular readahead code take care of this >> * situation. >> */ >> >> the reason for an unchanged async_size is also beyond my understanding. > > This isn't because we couldn't allocate a folio, this is when we > allocated folios, tried to read them and we failed to submit the I/O. > This is a pretty rare occurrence under normal conditions. I beg to differ, the code is reached when there is no folio support or ra->size < 4 (not considered in this discussion) or falling throug when !err, err is set by: err = ra_alloc_folio(ractl, index, mark, order, gfp); if (err) break; isn't the reading done by: read_pages(ractl); which does not set err! /Anders