From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753258Ab0CXAG6 (ORCPT ); Tue, 23 Mar 2010 20:06:58 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:47655 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752200Ab0CXAG4 (ORCPT ); Tue, 23 Mar 2010 20:06:56 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Wed, 24 Mar 2010 09:03:12 +0900 From: KAMEZAWA Hiroyuki To: Mel Gorman Cc: Andrew Morton , Andrea Arcangeli , Christoph Lameter , Adam Litke , Avi Kivity , David Rientjes , Minchan Kim , KOSAKI Motohiro , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 05/11] Export unusable free space index via /proc/unusable_index Message-Id: <20100324090312.4e1cc725.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <1269347146-7461-6-git-send-email-mel@csn.ul.ie> References: <1269347146-7461-1-git-send-email-mel@csn.ul.ie> <1269347146-7461-6-git-send-email-mel@csn.ul.ie> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 3.0.1 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 ? Thanks, -Kame