From: Mel Gorman <mel@csn.ul.ie> To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Andrea Arcangeli <aarcange@redhat.com>, Christoph Lameter <cl@linux-foundation.org>, Adam Litke <agl@us.ibm.com>, Avi Kivity <avi@redhat.com>, David Rientjes <rientjes@google.com>, Rik van Riel <riel@redhat.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 06/11] Export fragmentation index via /proc/extfrag_index Date: Tue, 23 Mar 2010 12:03:30 +0000 [thread overview] Message-ID: <20100323120329.GE9590@csn.ul.ie> (raw) In-Reply-To: <20100323050910.A473.A69D9226@jp.fujitsu.com> On Tue, Mar 23, 2010 at 09:22:04AM +0900, KOSAKI Motohiro wrote: > > > > + /* > > > > + * Index is between 0 and 1 so return within 3 decimal places > > > > + * > > > > + * 0 => allocation would fail due to lack of memory > > > > + * 1 => allocation would fail due to fragmentation > > > > + */ > > > > + return 1000 - ( (1000+(info->free_pages * 1000 / requested)) / info->free_blocks_total); > > > > +} > > > > > > Dumb question. > > > your paper (http://portal.acm.org/citation.cfm?id=1375634.1375641) says > > > fragmentation_index = 1 - (TotalFree/SizeRequested)/BlocksFree > > > but your code have extra '1000+'. Why? > > > > To get an approximation to three decimal places. > > Do you mean this is poor man's round up logic? Not exactly. The intention is to have a value of 968 instead of 0.968231. i.e. instead of a value between 0 and 1, it'll be a value between 0 and 1000 that matches the first three digits after the decimal place. > Why don't you use DIV_ROUND_UP? likes following, > > return 1000 - (DIV_ROUND_UP(info->free_pages * 1000 / requested) / info->free_blocks_total); > Because it's not doing the same thing unless I missed something. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mel@csn.ul.ie> To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Andrea Arcangeli <aarcange@redhat.com>, Christoph Lameter <cl@linux-foundation.org>, Adam Litke <agl@us.ibm.com>, Avi Kivity <avi@redhat.com>, David Rientjes <rientjes@google.com>, Rik van Riel <riel@redhat.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 06/11] Export fragmentation index via /proc/extfrag_index Date: Tue, 23 Mar 2010 12:03:30 +0000 [thread overview] Message-ID: <20100323120329.GE9590@csn.ul.ie> (raw) In-Reply-To: <20100323050910.A473.A69D9226@jp.fujitsu.com> On Tue, Mar 23, 2010 at 09:22:04AM +0900, KOSAKI Motohiro wrote: > > > > + /* > > > > + * Index is between 0 and 1 so return within 3 decimal places > > > > + * > > > > + * 0 => allocation would fail due to lack of memory > > > > + * 1 => allocation would fail due to fragmentation > > > > + */ > > > > + return 1000 - ( (1000+(info->free_pages * 1000 / requested)) / info->free_blocks_total); > > > > +} > > > > > > Dumb question. > > > your paper (http://portal.acm.org/citation.cfm?id=1375634.1375641) says > > > fragmentation_index = 1 - (TotalFree/SizeRequested)/BlocksFree > > > but your code have extra '1000+'. Why? > > > > To get an approximation to three decimal places. > > Do you mean this is poor man's round up logic? Not exactly. The intention is to have a value of 968 instead of 0.968231. i.e. instead of a value between 0 and 1, it'll be a value between 0 and 1000 that matches the first three digits after the decimal place. > Why don't you use DIV_ROUND_UP? likes following, > > return 1000 - (DIV_ROUND_UP(info->free_pages * 1000 / requested) / info->free_blocks_total); > Because it's not doing the same thing unless I missed something. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2010-03-23 12:03 UTC|newest] Thread overview: 216+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-03-12 16:41 [PATCH 0/11] Memory Compaction v4 Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-12 16:41 ` [PATCH 01/11] mm,migration: Take a reference to the anon_vma before migrating Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-14 15:01 ` Minchan Kim 2010-03-14 15:01 ` Minchan Kim 2010-03-15 5:06 ` KAMEZAWA Hiroyuki 2010-03-15 5:06 ` KAMEZAWA Hiroyuki 2010-03-17 1:44 ` KOSAKI Motohiro 2010-03-17 1:44 ` KOSAKI Motohiro 2010-03-17 11:45 ` Mel Gorman 2010-03-17 11:45 ` Mel Gorman 2010-03-17 16:38 ` Christoph Lameter 2010-03-17 16:38 ` Christoph Lameter 2010-03-18 11:12 ` Mel Gorman 2010-03-18 11:12 ` Mel Gorman 2010-03-18 16:31 ` Christoph Lameter 2010-03-18 16:31 ` Christoph Lameter 2010-03-12 16:41 ` [PATCH 02/11] mm,migration: Do not try to migrate unmapped anonymous pages Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-15 0:28 ` Minchan Kim 2010-03-15 0:28 ` Minchan Kim 2010-03-15 5:34 ` KAMEZAWA Hiroyuki 2010-03-15 5:34 ` KAMEZAWA Hiroyuki 2010-03-15 6:28 ` Minchan Kim 2010-03-15 6:28 ` Minchan Kim 2010-03-15 6:44 ` KAMEZAWA Hiroyuki 2010-03-15 6:44 ` KAMEZAWA Hiroyuki 2010-03-15 7:09 ` KAMEZAWA Hiroyuki 2010-03-15 7:09 ` KAMEZAWA Hiroyuki 2010-03-15 13:48 ` Minchan Kim 2010-03-15 13:48 ` Minchan Kim 2010-03-15 7:11 ` Minchan Kim 2010-03-15 7:11 ` Minchan Kim 2010-03-15 11:28 ` Mel Gorman 2010-03-15 11:28 ` Mel Gorman 2010-03-15 12:48 ` Minchan Kim 2010-03-15 12:48 ` Minchan Kim 2010-03-15 14:21 ` Mel Gorman 2010-03-15 14:21 ` Mel Gorman 2010-03-15 14:33 ` Minchan Kim 2010-03-15 14:33 ` Minchan Kim 2010-03-15 23:49 ` KAMEZAWA Hiroyuki 2010-03-15 23:49 ` KAMEZAWA Hiroyuki 2010-03-17 2:12 ` KAMEZAWA Hiroyuki 2010-03-17 2:12 ` KAMEZAWA Hiroyuki 2010-03-17 3:00 ` Minchan Kim 2010-03-17 3:00 ` Minchan Kim 2010-03-17 3:15 ` KAMEZAWA Hiroyuki 2010-03-17 3:15 ` KAMEZAWA Hiroyuki 2010-03-17 4:15 ` Minchan Kim 2010-03-17 4:15 ` Minchan Kim 2010-03-17 4:19 ` KAMEZAWA Hiroyuki 2010-03-17 4:19 ` KAMEZAWA Hiroyuki 2010-03-17 16:41 ` Christoph Lameter 2010-03-17 16:41 ` Christoph Lameter 2010-03-18 0:30 ` KAMEZAWA Hiroyuki 2010-03-18 0:30 ` KAMEZAWA Hiroyuki 2010-03-17 12:07 ` Mel Gorman 2010-03-17 12:07 ` Mel Gorman 2010-03-17 2:03 ` KOSAKI Motohiro 2010-03-17 2:03 ` KOSAKI Motohiro 2010-03-17 11:51 ` Mel Gorman 2010-03-17 11:51 ` Mel Gorman 2010-03-18 0:48 ` KOSAKI Motohiro 2010-03-18 0:48 ` KOSAKI Motohiro 2010-03-18 11:14 ` Mel Gorman 2010-03-18 11:14 ` Mel Gorman 2010-03-19 6:21 ` KOSAKI Motohiro 2010-03-19 6:21 ` KOSAKI Motohiro 2010-03-19 8:59 ` Mel Gorman 2010-03-19 8:59 ` Mel Gorman 2010-03-25 2:49 ` KOSAKI Motohiro 2010-03-25 2:49 ` KOSAKI Motohiro 2010-03-25 8:32 ` Mel Gorman 2010-03-25 8:32 ` Mel Gorman 2010-03-25 8:56 ` KOSAKI Motohiro 2010-03-25 8:56 ` KOSAKI Motohiro 2010-03-25 9:18 ` Mel Gorman 2010-03-25 9:18 ` Mel Gorman 2010-03-25 9:02 ` KAMEZAWA Hiroyuki 2010-03-25 9:02 ` KAMEZAWA Hiroyuki 2010-03-25 9:09 ` KOSAKI Motohiro 2010-03-25 9:09 ` KOSAKI Motohiro 2010-03-25 9:08 ` KAMEZAWA Hiroyuki 2010-03-25 9:08 ` KAMEZAWA Hiroyuki 2010-03-25 9:21 ` Mel Gorman 2010-03-25 9:21 ` Mel Gorman 2010-03-25 9:41 ` KAMEZAWA Hiroyuki 2010-03-25 9:41 ` KAMEZAWA Hiroyuki 2010-03-25 9:59 ` KOSAKI Motohiro 2010-03-25 9:59 ` KOSAKI Motohiro 2010-03-25 10:12 ` KAMEZAWA Hiroyuki 2010-03-25 10:12 ` KAMEZAWA Hiroyuki 2010-03-25 13:39 ` Mel Gorman 2010-03-25 13:39 ` Mel Gorman 2010-03-26 3:07 ` KOSAKI Motohiro 2010-03-26 3:07 ` KOSAKI Motohiro 2010-03-26 13:49 ` Mel Gorman 2010-03-26 13:49 ` Mel Gorman 2010-03-25 15:29 ` Minchan Kim 2010-03-25 15:29 ` Minchan Kim 2010-03-26 0:58 ` KAMEZAWA Hiroyuki 2010-03-26 0:58 ` KAMEZAWA Hiroyuki 2010-03-26 1:39 ` Minchan Kim 2010-03-26 1:39 ` Minchan Kim 2010-03-25 14:35 ` Christoph Lameter 2010-03-25 14:35 ` Christoph Lameter 2010-03-25 16:16 ` Minchan Kim 2010-03-25 16:16 ` Minchan Kim 2010-03-12 16:41 ` [PATCH 03/11] mm: Share the anon_vma ref counts between KSM and page migration Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-12 17:14 ` Rik van Riel 2010-03-12 17:14 ` Rik van Riel 2010-03-15 5:35 ` KAMEZAWA Hiroyuki 2010-03-15 5:35 ` KAMEZAWA Hiroyuki 2010-03-17 2:06 ` KOSAKI Motohiro 2010-03-17 2:06 ` KOSAKI Motohiro 2010-03-12 16:41 ` [PATCH 04/11] Allow CONFIG_MIGRATION to be set without CONFIG_NUMA or memory hot-remove Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-17 2:28 ` KOSAKI Motohiro 2010-03-17 2:28 ` KOSAKI Motohiro 2010-03-17 11:32 ` Mel Gorman 2010-03-17 11:32 ` Mel Gorman 2010-03-17 16:37 ` Christoph Lameter 2010-03-17 16:37 ` Christoph Lameter 2010-03-17 23:56 ` KOSAKI Motohiro 2010-03-17 23:56 ` KOSAKI Motohiro 2010-03-18 11:24 ` Mel Gorman 2010-03-18 11:24 ` Mel Gorman 2010-03-19 6:21 ` KOSAKI Motohiro 2010-03-19 6:21 ` KOSAKI Motohiro 2010-03-19 10:16 ` Mel Gorman 2010-03-19 10:16 ` Mel Gorman 2010-03-25 3:28 ` KOSAKI Motohiro 2010-03-25 3:28 ` KOSAKI Motohiro 2010-03-12 16:41 ` [PATCH 05/11] Export unusable free space index via /proc/unusable_index Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-15 5:41 ` KAMEZAWA Hiroyuki 2010-03-15 5:41 ` KAMEZAWA Hiroyuki 2010-03-15 9:48 ` Mel Gorman 2010-03-15 9:48 ` Mel Gorman 2010-03-17 2:42 ` KOSAKI Motohiro 2010-03-17 2:42 ` KOSAKI Motohiro 2010-03-12 16:41 ` [PATCH 06/11] Export fragmentation index via /proc/extfrag_index Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-17 2:49 ` KOSAKI Motohiro 2010-03-17 2:49 ` KOSAKI Motohiro 2010-03-17 11:33 ` Mel Gorman 2010-03-17 11:33 ` Mel Gorman 2010-03-23 0:22 ` KOSAKI Motohiro 2010-03-23 0:22 ` KOSAKI Motohiro 2010-03-23 12:03 ` Mel Gorman [this message] 2010-03-23 12:03 ` Mel Gorman 2010-03-25 2:47 ` KOSAKI Motohiro 2010-03-25 2:47 ` KOSAKI Motohiro 2010-03-25 8:47 ` Mel Gorman 2010-03-25 8:47 ` Mel Gorman 2010-03-25 11:20 ` KOSAKI Motohiro 2010-03-25 11:20 ` KOSAKI Motohiro 2010-03-25 14:11 ` Mel Gorman 2010-03-25 14:11 ` Mel Gorman 2010-03-26 3:10 ` KOSAKI Motohiro 2010-03-26 3:10 ` KOSAKI Motohiro 2010-03-12 16:41 ` [PATCH 07/11] Memory compaction core Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-15 13:44 ` Minchan Kim 2010-03-15 13:44 ` Minchan Kim 2010-03-15 14:41 ` Mel Gorman 2010-03-15 14:41 ` Mel Gorman 2010-03-17 10:31 ` KOSAKI Motohiro 2010-03-17 10:31 ` KOSAKI Motohiro 2010-03-17 11:40 ` Mel Gorman 2010-03-17 11:40 ` Mel Gorman 2010-03-18 2:35 ` KOSAKI Motohiro 2010-03-18 2:35 ` KOSAKI Motohiro 2010-03-18 11:43 ` Mel Gorman 2010-03-18 11:43 ` Mel Gorman 2010-03-19 6:21 ` KOSAKI Motohiro 2010-03-19 6:21 ` KOSAKI Motohiro 2010-03-18 17:08 ` Mel Gorman 2010-03-18 17:08 ` Mel Gorman 2010-03-12 16:41 ` [PATCH 08/11] Add /proc trigger for memory compaction Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-17 3:18 ` KOSAKI Motohiro 2010-03-17 3:18 ` KOSAKI Motohiro 2010-03-12 16:41 ` [PATCH 09/11] Add /sys trigger for per-node " Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-17 3:18 ` KOSAKI Motohiro 2010-03-17 3:18 ` KOSAKI Motohiro 2010-03-12 16:41 ` [PATCH 10/11] Direct compact when a high-order allocation fails Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-16 2:47 ` Minchan Kim 2010-03-16 2:47 ` Minchan Kim 2010-03-19 6:21 ` KOSAKI Motohiro 2010-03-19 6:21 ` KOSAKI Motohiro 2010-03-19 6:31 ` KOSAKI Motohiro 2010-03-19 6:31 ` KOSAKI Motohiro 2010-03-19 10:10 ` Mel Gorman 2010-03-19 10:10 ` Mel Gorman 2010-03-25 11:22 ` KOSAKI Motohiro 2010-03-25 11:22 ` KOSAKI Motohiro 2010-03-19 10:09 ` Mel Gorman 2010-03-19 10:09 ` Mel Gorman 2010-03-25 11:08 ` KOSAKI Motohiro 2010-03-25 11:08 ` KOSAKI Motohiro 2010-03-25 15:11 ` Mel Gorman 2010-03-25 15:11 ` Mel Gorman 2010-03-26 6:01 ` KOSAKI Motohiro 2010-03-26 6:01 ` KOSAKI Motohiro 2010-03-12 16:41 ` [PATCH 11/11] Do not compact within a preferred zone after a compaction failure Mel Gorman 2010-03-12 16:41 ` Mel Gorman 2010-03-23 12:25 [PATCH 0/11] Memory Compaction v5 Mel Gorman 2010-03-23 12:25 ` [PATCH 06/11] Export fragmentation index via /proc/extfrag_index Mel Gorman 2010-03-23 12:25 ` Mel Gorman 2010-03-23 17:37 ` Christoph Lameter 2010-03-23 17:37 ` Christoph Lameter
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