From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f176.google.com (mail-ie0-f176.google.com [209.85.223.176]) by kanga.kvack.org (Postfix) with ESMTP id B49246B0035 for ; Thu, 3 Jul 2014 14:42:34 -0400 (EDT) Received: by mail-ie0-f176.google.com with SMTP id at1so687457iec.35 for ; Thu, 03 Jul 2014 11:42:34 -0700 (PDT) Received: from e28smtp02.in.ibm.com (e28smtp02.in.ibm.com. [122.248.162.2]) by mx.google.com with ESMTPS id e9si8354443ict.95.2014.07.03.11.42.32 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Thu, 03 Jul 2014 11:42:33 -0700 (PDT) Received: from /spool/local by e28smtp02.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 4 Jul 2014 00:12:11 +0530 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 15E79E0045 for ; Fri, 4 Jul 2014 00:13:30 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s63IgPYs61407302 for ; Fri, 4 Jul 2014 00:12:25 +0530 Received: from d28av05.in.ibm.com (localhost [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s63Ig8te031046 for ; Fri, 4 Jul 2014 00:12:08 +0530 Message-ID: <53B5A343.4090402@linux.vnet.ibm.com> Date: Fri, 04 Jul 2014 00:08:59 +0530 From: Raghavendra K T MIME-Version: 1.0 Subject: Re: [PATCH] mm readahead: Fix sys_readahead breakage by reverting 2MB limit (bug 79111) References: <1404392547-11648-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> <53B59CB5.9060004@linux.vnet.ibm.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Linus Torvalds Cc: Andrew Morton , Fengguang Wu , David Cohen , Al Viro , Damien Ramonda , Jan Kara , David Rientjes , Nishanth Aravamudan , linux-mm , Linux Kernel Mailing List On 07/03/2014 11:59 PM, Linus Torvalds wrote: > On Thu, Jul 3, 2014 at 11:22 AM, Linus Torvalds > wrote: >> >> So the bugzilla entry worries me a bit - we definitely do not want to >> regress in case somebody really relied on timing - but without more >> specific information I still think the real bug is just in the >> man-page. > > Side note: the 2MB limit may be too small. 2M is peanuts on modern > machines, even for fairly slow IO, and there are lots of files (like > glibc etc) that people might want to read-ahead during boot. We > already do bigger read-ahead if people just do "read()" system calls. > So I could certainly imagine that we should increase it. > > I do *not* think we should bow down to insane man-pages that have > always been wrong, though, and I don't think we should increase it to > "let's just read-ahead a whole ISO image" kind of sizes.. Okay, how about something like 256MB? I would be happy to send a patch for that change. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org