From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id 4A6448D0039 for ; Fri, 28 Jan 2011 13:04:18 -0500 (EST) Message-ID: <4D430506.2070502@redhat.com> Date: Fri, 28 Jan 2011 13:03:50 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: too big min_free_kbytes References: <20110127134057.GA32039@csn.ul.ie> <20110127152755.GB30919@random.random> <20110127160301.GA29291@csn.ul.ie> <20110127185215.GE16981@random.random> <20110127213106.GA25933@csn.ul.ie> <4D41FD2F.3050006@redhat.com> <20110128103539.GA14669@csn.ul.ie> <20110128162831.GH16981@random.random> <20110128164624.GA23905@csn.ul.ie> <4D42F9E3.2010605@redhat.com> <20110128174644.GM16981@random.random> In-Reply-To: <20110128174644.GM16981@random.random> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Andrea Arcangeli Cc: Mel Gorman , Shaohua Li , Andrew Morton , linux-mm , "Chen, Tim C" List-ID: On 01/28/2011 12:46 PM, Andrea Arcangeli wrote: > My whole point in claiming it can't affect the balancing of the lrus, > is that the real lru rotation is entirely controlled by the > allocator. It doesn't matter if kswapd stops at high or high+gap, for > any zone at any time, as long as the allocator only allocates from one > zone or the other. And if the allocator allocates from all zones in a > perfectly balanced way, again kswapd will shrink in a perfectly > balanced way over time regardless of high or high+gap. My point is, the behaviour you describe would be WRONG :) The reason is that the different zones can contain data that is either heavily used or rarely used, often some mixture of the two, but sometimes the zones are out of balance in how much the data in memory gets touched. We need to reclaim and reuse the lightly used memory a little faster than the heavily used memory, to even out the memory pressure between zones. -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org