From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753211Ab0CXAQL (ORCPT ); Tue, 23 Mar 2010 20:16:11 -0400 Received: from mail-pv0-f174.google.com ([74.125.83.174]:41519 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751406Ab0CXAQJ convert rfc822-to-8bit (ORCPT ); Tue, 23 Mar 2010 20:16:09 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=C3eay8QLGtfi7nirKeLVDI6tBtXvYk0/VXsG1MYRx1Iz0/Sf/GEbYtjFWyEJdzYkVz Rm3EN3INlR9Lt3OFDVb9aAHR1tenpqLC+bDhczDmyMjNxFBTyu77XW54qjdPQ0LJcigA T9f1JDIOBXdu07Sa6FZZ5Kc1jOs9EHEaEDlQQ= MIME-Version: 1.0 In-Reply-To: <20100324090312.4e1cc725.kamezawa.hiroyu@jp.fujitsu.com> References: <1269347146-7461-1-git-send-email-mel@csn.ul.ie> <1269347146-7461-6-git-send-email-mel@csn.ul.ie> <20100324090312.4e1cc725.kamezawa.hiroyu@jp.fujitsu.com> Date: Wed, 24 Mar 2010 09:16:07 +0900 Message-ID: <28c262361003231716k54ca1ae8u92793be7f2fdf374@mail.gmail.com> Subject: Re: [PATCH 05/11] Export unusable free space index via /proc/unusable_index From: Minchan Kim To: KAMEZAWA Hiroyuki Cc: Mel Gorman , Andrew Morton , Andrea Arcangeli , Christoph Lameter , Adam Litke , Avi Kivity , David Rientjes , KOSAKI Motohiro , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Kame. On Wed, Mar 24, 2010 at 9:03 AM, KAMEZAWA Hiroyuki wrote: > On Tue, 23 Mar 2010 12:25:40 +0000 > Mel Gorman wrote: > >> Unusable free space index is a measure of external fragmentation that >> takes the allocation size into account. For the most part, the huge page >> size will be the size of interest but not necessarily so it is exported >> on a per-order and per-zone basis via /proc/unusable_index. >> >> The index is a value between 0 and 1. It can be expressed as a >> percentage by multiplying by 100 as documented in >> Documentation/filesystems/proc.txt. >> >> Signed-off-by: Mel Gorman >> Reviewed-by: Minchan Kim >> Reviewed-by: KOSAKI Motohiro >> Acked-by: Rik van Riel >> --- >>  Documentation/filesystems/proc.txt |   13 ++++- >>  mm/vmstat.c                        |  120 +++++++++++++++++++++++++++++++++ >>  2 files changed, 132 insertions(+), 1 deletions(-) >> >> diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt >> index 5e132b5..5c4b0fb 100644 >> --- a/Documentation/filesystems/proc.txt >> +++ b/Documentation/filesystems/proc.txt >> @@ -452,6 +452,7 @@ Table 1-5: Kernel info in /proc >>   sys         See chapter 2 >>   sysvipc     Info of SysVIPC Resources (msg, sem, shm)               (2.4) >>   tty      Info of tty drivers >> + unusable_index Additional page allocator information (see text)(2.5) >>   uptime      System uptime >>   version     Kernel version >>   video            bttv info of video resources                       (2.4) >> @@ -609,7 +610,7 @@ ZONE_DMA, 4 chunks of 2^1*PAGE_SIZE in ZONE_DMA, 101 chunks of 2^4*PAGE_SIZE >>  available in ZONE_NORMAL, etc... >> >>  More information relevant to external fragmentation can be found in >> -pagetypeinfo. >> +pagetypeinfo and unusable_index >> >>  > cat /proc/pagetypeinfo >>  Page block order: 9 >> @@ -650,6 +651,16 @@ unless memory has been mlock()'d. Some of the Reclaimable blocks should >>  also be allocatable although a lot of filesystem metadata may have to be >>  reclaimed to achieve this. >> >> +> cat /proc/unusable_index >> +Node 0, zone      DMA 0.000 0.000 0.000 0.001 0.005 0.013 0.021 0.037 0.037 0.101 0.230 >> +Node 0, zone   Normal 0.000 0.000 0.000 0.001 0.002 0.002 0.005 0.015 0.028 0.028 0.054 >> + >> +The unusable free space index measures how much of the available free >> +memory cannot be used to satisfy an allocation of a given size and is a >> +value between 0 and 1. The higher the value, the more of free memory is >> +unusable and by implication, the worse the external fragmentation is. This >> +can be expressed as a percentage by multiplying by 100. >> + >>  .............................................................................. >> >>  meminfo: >> diff --git a/mm/vmstat.c b/mm/vmstat.c >> index 7f760cb..ca42e10 100644 >> --- a/mm/vmstat.c >> +++ b/mm/vmstat.c >> @@ -453,6 +453,106 @@ static int frag_show(struct seq_file *m, void *arg) >>       return 0; >>  } >> >> + >> +struct contig_page_info { >> +     unsigned long free_pages; >> +     unsigned long free_blocks_total; >> +     unsigned long free_blocks_suitable; >> +}; >> + >> +/* >> + * Calculate the number of free pages in a zone, how many contiguous >> + * pages are free and how many are large enough to satisfy an allocation of >> + * the target size. Note that this function makes to attempt to estimate >> + * how many suitable free blocks there *might* be if MOVABLE pages were >> + * migrated. Calculating that is possible, but expensive and can be >> + * figured out from userspace >> + */ >> +static void fill_contig_page_info(struct zone *zone, >> +                             unsigned int suitable_order, >> +                             struct contig_page_info *info) >> +{ >> +     unsigned int order; >> + >> +     info->free_pages = 0; >> +     info->free_blocks_total = 0; >> +     info->free_blocks_suitable = 0; >> + >> +     for (order = 0; order < MAX_ORDER; order++) { >> +             unsigned long blocks; >> + >> +             /* Count number of free blocks */ >> +             blocks = zone->free_area[order].nr_free; >> +             info->free_blocks_total += blocks; > > ....for what this free_blocks_total is ? It's used by fragmentation_index in [06/11]. > > Thanks, > -Kame > > -- Kind regards, Minchan Kim