From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yh0-f43.google.com (mail-yh0-f43.google.com [209.85.213.43]) by kanga.kvack.org (Postfix) with ESMTP id B604A6B0035 for ; Wed, 8 Jan 2014 06:50:31 -0500 (EST) Received: by mail-yh0-f43.google.com with SMTP id a41so344150yho.2 for ; Wed, 08 Jan 2014 03:50:31 -0800 (PST) Received: from e28smtp03.in.ibm.com (e28smtp03.in.ibm.com. [122.248.162.3]) by mx.google.com with ESMTPS id o28si604675yhd.216.2014.01.08.03.50.25 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 08 Jan 2014 03:50:30 -0800 (PST) Received: from /spool/local by e28smtp03.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 8 Jan 2014 17:20:13 +0530 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id A06091258059 for ; Wed, 8 Jan 2014 17:21:39 +0530 (IST) Received: from d28av03.in.ibm.com (d28av03.in.ibm.com [9.184.220.65]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s08Bo4Xw43581678 for ; Wed, 8 Jan 2014 17:20:07 +0530 Received: from d28av03.in.ibm.com (localhost [127.0.0.1]) by d28av03.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s08Bo6PW015125 for ; Wed, 8 Jan 2014 17:20:06 +0530 Message-ID: <52CD3D36.1010706@linux.vnet.ibm.com> Date: Wed, 08 Jan 2014 17:27:42 +0530 From: Raghavendra K T MIME-Version: 1.0 Subject: Re: [RFC PATCH V3] mm readahead: Fix the readahead fail in case of empty numa node References: <1389003715-29733-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> <20140106141300.4e1c950d45c614d6c29bdd8f@linux-foundation.org> <52CD1113.2070003@linux.vnet.ibm.com> <20140108104713.GB8256@quack.suse.cz> In-Reply-To: <20140108104713.GB8256@quack.suse.cz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Jan Kara Cc: Andrew Morton , Fengguang Wu , David Cohen , Al Viro , Damien Ramonda , Linus , linux-mm@kvack.org, linux-kernel@vger.kernel.org On 01/08/2014 04:17 PM, Jan Kara wrote: > On Wed 08-01-14 14:19:23, Raghavendra K T wrote: >> On 01/07/2014 03:43 AM, Andrew Morton wrote: >>> On Mon, 6 Jan 2014 15:51:55 +0530 Raghavendra K T wrote: [...] >> But having said that I am not able to get an idea of sane implementation >> to solve this readahead failure bug overcoming the anomaly you pointed >> :(. hints/ideas.. ?? please let me know. > So if we would be happy with just fixing corner cases like this, we might > use total node memory size to detect them, can't we? If total node memory > size is 0, we can use 16 MB (or global number of free pages / 2 if we would > be uneasy with fixed 16 MB limit) as an upperbound... > Thanks Honza. This seems to be more sensible option, I 'll send the patch with that change (including 16MB limit if nobody disagrees). -- 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