From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx141.postini.com [74.125.245.141]) by kanga.kvack.org (Postfix) with SMTP id 2F1DE6B0006 for ; Tue, 12 Mar 2013 21:31:36 -0400 (EDT) Received: by mail-ob0-f170.google.com with SMTP id wc20so518714obb.29 for ; Tue, 12 Mar 2013 18:31:35 -0700 (PDT) Message-ID: <513FD6F2.5060804@gmail.com> Date: Wed, 13 Mar 2013 09:31:30 +0800 From: Will Huck MIME-Version: 1.0 Subject: Re: Swap defragging References: <20130308023511.GD23767@cmpxchg.org> <513A97C5.7020008@gmail.com> <20130312165247.GB1953@cmpxchg.org> In-Reply-To: <20130312165247.GB1953@cmpxchg.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Raymond Jennings , Linux Memory Management List Hi Johannes, On 03/13/2013 12:52 AM, Johannes Weiner wrote: > On Sat, Mar 09, 2013 at 10:00:37AM +0800, Will Huck wrote: >> Hi Johannes, >> On 03/08/2013 10:35 AM, Johannes Weiner wrote: >>> On Thu, Mar 07, 2013 at 06:07:23PM -0800, Raymond Jennings wrote: >>>> Just a two cent question, but is there any merit to having the kernel >>>> defragment swap space? >>> That is a good question. >>> >>> Swap does fragment quite a bit, and there are several reasons for >>> that. >> Are there any tools to test and monitor swap subsystem and page >> reclaim subsystem? pgscan_kswapd_dma 0 pgscan_kswapd_dma32 0 pgscan_kswapd_normal 0 pgscan_kswapd_movable 0 pgscan_direct_dma 0 pgscan_direct_dma32 0 pgscan_direct_normal 0 pgscan_direct_movable 0 pgscan_direct_throttle 0 zone_reclaim_failed 0 pginodesteal 0 slabs_scanned 328704 slab cache is scaned but file-backed/swap-backed pages are not scanned, why? > seekwatcher is great to see the IO patterns. Anything that uses > anonymous memory can test swap: a java job, multiplying matrixes, > kernel builds etc. I mostly log /proc/vmstat by taking snapshots at a > regular interval during the workload, then plot and visually correlate > the swapin/swapout counters with the individual LRU sizes, page fault > rate, what have you, to get a feeling for what it's doing. -- 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