From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f176.google.com (mail-pd0-f176.google.com [209.85.192.176]) by kanga.kvack.org (Postfix) with ESMTP id 52BCE6B00E8 for ; Tue, 18 Mar 2014 03:08:01 -0400 (EDT) Received: by mail-pd0-f176.google.com with SMTP id r10so6676165pdi.35 for ; Tue, 18 Mar 2014 00:08:01 -0700 (PDT) Received: from e23smtp02.au.ibm.com (e23smtp02.au.ibm.com. [202.81.31.144]) by mx.google.com with ESMTPS id f1si17016280pbn.76.2014.03.18.00.07.59 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 18 Mar 2014 00:08:00 -0700 (PDT) Received: from /spool/local by e23smtp02.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 18 Mar 2014 17:07:56 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 6BBB72BB0056 for ; Tue, 18 Mar 2014 18:07:53 +1100 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s2I6lgut20185216 for ; Tue, 18 Mar 2014 17:47:44 +1100 Received: from d23av03.au.ibm.com (localhost [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s2I77pKU004889 for ; Tue, 18 Mar 2014 18:07:51 +1100 Message-ID: <5327F218.1000506@linux.vnet.ibm.com> Date: Tue, 18 Mar 2014 12:43:28 +0530 From: Raghavendra K T MIME-Version: 1.0 Subject: Re: [PATCH V6 ] mm readahead: Fix readahead fail for memoryless cpu and limit readahead pages References: <1392708338-19685-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> <20140218094920.GB29660@quack.suse.cz> <53034C66.90707@linux.vnet.ibm.com> <871ty1zig4.fsf@redhat.com> In-Reply-To: <871ty1zig4.fsf@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Madper Xie Cc: Jan Kara , Andrew Morton , Fengguang Wu , David Cohen , Al Viro , Damien Ramonda , rientjes@google.com, Linus , nacc@linux.vnet.ibm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org On 03/17/2014 07:37 AM, Madper Xie wrote: > > Raghavendra K T writes: > >> On 02/18/2014 03:19 PM, Jan Kara wrote: >>> On Tue 18-02-14 12:55:38, Raghavendra K T wrote: > Hi. Just a concern. Will the performance reduce on some special storage > backend? E.g. tape. > The existent applications may using readahead for userspace I/O schedule > to decrease seeking time. I have not tested the patch on such systems yet unfortunately :(. Sequential read with huge file has not suffered on disk based system, but I think, I should be honest enough not to guess the effect on tape. -- 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