Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752071Ab0DMMng (ORCPT ); Tue, 13 Apr 2010 08:43:36 -0400 Received: from gir.skynet.ie ([193.1.99.77]:49067 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751726Ab0DMMnf (ORCPT ); Tue, 13 Apr 2010 08:43:35 -0400 Date: Tue, 13 Apr 2010 13:43:15 +0100 From: Mel Gorman To: Andrew Morton Cc: Andrea Arcangeli , Christoph Lameter , Adam Litke , Avi Kivity , David Rientjes , Minchan Kim , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 06/14] Export fragmentation index via /proc/extfrag_index Message-ID: <20100413124315.GW25756@csn.ul.ie> References: <1270224168-14775-1-git-send-email-mel@csn.ul.ie> <1270224168-14775-7-git-send-email-mel@csn.ul.ie> <20100406170542.fe9b9f33.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20100406170542.fe9b9f33.akpm@linux-foundation.org> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7777 Lines: 230 On Tue, Apr 06, 2010 at 05:05:42PM -0700, Andrew Morton wrote: > On Fri, 2 Apr 2010 17:02:40 +0100 > > Fragmentation index is a value that makes sense when an allocation of a > > given size would fail. The index indicates whether an allocation failure is > > due to a lack of memory (values towards 0) or due to external fragmentation > > (value towards 1). 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/extfrag_index > > (/proc/sys/vm?) > > Like unusable_index, this seems awfully specialised. Perhaps we could > hide it under CONFIG_MEL, or even put it in debugfs with the intention > of removing it in 6 or 12 months time. > ==== CUT HERE ==== mm,compaction: Move extfrag_index to debugfs extfrag_index can be worked out from userspace but for debugging and tuning compaction, it'd be best for all users to have the same information. This patch moves extfrag_index to debugfs where it is both easier to configure out and remove at some future date. This is a fix to the patch "Export fragmentation index via /proc/extfrag_index". When merged, it'll collide with the patch "Direct compact when a high-order allocation fails" but the resolution is relatively straight forward - preserve the fragmentation_index functions and delete the proc-related functions as they are now at the bottom of the file under ifdef CONFIG_DEBUG_FS. Signed-off-by: Mel Gorman --- Documentation/filesystems/proc.txt | 14 +---- mm/vmstat.c | 110 ++++++++++++++++++------------------ 2 files changed, 57 insertions(+), 67 deletions(-) diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 66ebc11..74d2605 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -422,7 +422,6 @@ Table 1-5: Kernel info in /proc filesystems Supported filesystems driver Various drivers grouped here, currently rtc (2.4) execdomains Execdomains, related to security (2.4) - extfrag_index Additional page allocator information (see text) (2.5) fb Frame Buffer devices (2.4) fs File system parameters, currently nfs/exports (2.4) ide Directory containing info about the IDE subsystem @@ -611,7 +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 and extfrag_index. +pagetypeinfo. > cat /proc/pagetypeinfo Page block order: 9 @@ -652,17 +651,6 @@ 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/extfrag_index -Node 0, zone DMA -1.000 -1.000 -1.000 -1.000 -1.000 -1.000 -1.000 -1.00 -Node 0, zone Normal -1.000 -1.000 -1.000 -1.000 -1.000 -1.000 -1.000 0.954 - -The external fragmentation index, is only meaningful if an allocation -would fail and indicates what the failure is due to. A value of -1 such as -in many of the examples above states that the allocation would succeed. -If it would fail, the value is between 0 and 1. A value tending towards -0 implies the allocation failed due to a lack of memory. A value tending -towards 1 implies it failed due to external fragmentation. - .............................................................................. meminfo: diff --git a/mm/vmstat.c b/mm/vmstat.c index 582dc77..f70da05 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -522,40 +522,6 @@ int fragmentation_index(unsigned int order, struct contig_page_info *info) return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total); } - -static void extfrag_show_print(struct seq_file *m, - pg_data_t *pgdat, struct zone *zone) -{ - unsigned int order; - int index; - - /* Alloc on stack as interrupts are disabled for zone walk */ - struct contig_page_info info; - - seq_printf(m, "Node %d, zone %8s ", - pgdat->node_id, - zone->name); - for (order = 0; order < MAX_ORDER; ++order) { - fill_contig_page_info(zone, order, &info); - index = fragmentation_index(order, &info); - seq_printf(m, "%d.%03d ", index / 1000, index % 1000); - } - - seq_putc(m, '\n'); -} - -/* - * Display fragmentation index for orders that allocations would fail for - */ -static int extfrag_show(struct seq_file *m, void *arg) -{ - pg_data_t *pgdat = (pg_data_t *)arg; - - walk_zones_in_node(m, pgdat, extfrag_show_print); - - return 0; -} - static void pagetypeinfo_showfree_print(struct seq_file *m, pg_data_t *pgdat, struct zone *zone) { @@ -706,25 +672,6 @@ static const struct file_operations pagetypeinfo_file_ops = { .release = seq_release, }; -static const struct seq_operations extfrag_op = { - .start = frag_start, - .next = frag_next, - .stop = frag_stop, - .show = extfrag_show, -}; - -static int extfrag_open(struct inode *inode, struct file *file) -{ - return seq_open(file, &extfrag_op); -} - -static const struct file_operations extfrag_file_ops = { - .open = extfrag_open, - .read = seq_read, - .llseek = seq_lseek, - .release = seq_release, -}; - #ifdef CONFIG_ZONE_DMA #define TEXT_FOR_DMA(xx) xx "_dma", #else @@ -1069,7 +1016,6 @@ static int __init setup_vmstat(void) #ifdef CONFIG_PROC_FS proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations); proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops); - proc_create("extfrag_index", S_IRUGO, NULL, &extfrag_file_ops); proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations); proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations); #endif @@ -1165,6 +1111,58 @@ static const struct file_operations unusable_file_ops = { .release = seq_release, }; +static void extfrag_show_print(struct seq_file *m, + pg_data_t *pgdat, struct zone *zone) +{ + unsigned int order; + int index; + + /* Alloc on stack as interrupts are disabled for zone walk */ + struct contig_page_info info; + + seq_printf(m, "Node %d, zone %8s ", + pgdat->node_id, + zone->name); + for (order = 0; order < MAX_ORDER; ++order) { + fill_contig_page_info(zone, order, &info); + index = fragmentation_index(order, &info); + seq_printf(m, "%d.%03d ", index / 1000, index % 1000); + } + + seq_putc(m, '\n'); +} + +/* + * Display fragmentation index for orders that allocations would fail for + */ +static int extfrag_show(struct seq_file *m, void *arg) +{ + pg_data_t *pgdat = (pg_data_t *)arg; + + walk_zones_in_node(m, pgdat, extfrag_show_print); + + return 0; +} + +static const struct seq_operations extfrag_op = { + .start = frag_start, + .next = frag_next, + .stop = frag_stop, + .show = extfrag_show, +}; + +static int extfrag_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &extfrag_op); +} + +static const struct file_operations extfrag_file_ops = { + .open = extfrag_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + static int __init extfrag_debug_init(void) { extfrag_debug_root = debugfs_create_dir("extfrag", NULL); @@ -1175,6 +1173,10 @@ static int __init extfrag_debug_init(void) extfrag_debug_root, NULL, &unusable_file_ops)) return -ENOMEM; + if (!debugfs_create_file("extfrag_index", 0444, + extfrag_debug_root, NULL, &extfrag_file_ops)) + return -ENOMEM; + return 0; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/