Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759479AbaGCS3l (ORCPT ); Thu, 3 Jul 2014 14:29:41 -0400 Received: from mail-vc0-f175.google.com ([209.85.220.175]:47491 "EHLO mail-vc0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753459AbaGCS3j (ORCPT ); Thu, 3 Jul 2014 14:29:39 -0400 MIME-Version: 1.0 In-Reply-To: References: <1404392547-11648-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> <53B59CB5.9060004@linux.vnet.ibm.com> Date: Thu, 3 Jul 2014 11:29:38 -0700 X-Google-Sender-Auth: vZNh72p28rPzNmErqC8FTEDqBuY Message-ID: Subject: Re: [PATCH] mm readahead: Fix sys_readahead breakage by reverting 2MB limit (bug 79111) From: Linus Torvalds To: Raghavendra K T Cc: Andrew Morton , Fengguang Wu , David Cohen , Al Viro , Damien Ramonda , Jan Kara , David Rientjes , Nishanth Aravamudan , linux-mm , Linux Kernel Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/