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Date: Tue, 13 Apr 2010 13:42:26 +0100
From: Mel Gorman <mel@....ul.ie>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Andrea Arcangeli <aarcange@...hat.com>,
Christoph Lameter <cl@...ux-foundation.org>,
Adam Litke <agl@...ibm.com>, Avi Kivity <avi@...hat.com>,
David Rientjes <rientjes@...gle.com>,
Minchan Kim <minchan.kim@...il.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
Rik van Riel <riel@...hat.com>, linux-kernel@...r.kernel.org,
linux-mm@...ck.org
Subject: Re: [PATCH 05/14] Export unusable free space index via
/proc/unusable_index
On Tue, Apr 06, 2010 at 05:05:37PM -0700, Andrew Morton wrote:
> <SNIP>
>
> All this code will be bloat for most people, I suspect. Can we find a
> suitable #ifdef wrapper to keep my cellphone happy?
>
==== CUT HERE ====
mm,compaction: Move unusable_index to debugfs
unusable_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 unusable free space index via
/proc/unusable_index"
Signed-off-by: Mel Gorman <mel@....ul.ie>
---
Documentation/filesystems/proc.txt | 13 +---
mm/vmstat.c | 183 ++++++++++++++++++++----------------
2 files changed, 105 insertions(+), 91 deletions(-)
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index e87775a..74d2605 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -453,7 +453,6 @@ 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)
@@ -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 unusable_index
+pagetypeinfo.
> cat /proc/pagetypeinfo
Page block order: 9
@@ -652,16 +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/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 2fb4986..0dcf08d 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -453,7 +453,6 @@ 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;
@@ -495,64 +494,6 @@ static void fill_contig_page_info(struct zone *zone,
}
}
-/*
- * Return an index indicating how much of the available free memory is
- * unusable for an allocation of the requested size.
- */
-static int unusable_free_index(unsigned int order,
- struct contig_page_info *info)
-{
- /* No free memory is interpreted as all free memory is unusable */
- if (info->free_pages == 0)
- return 1000;
-
- /*
- * Index should be a value between 0 and 1. Return a value to 3
- * decimal places.
- *
- * 0 => no fragmentation
- * 1 => high fragmentation
- */
- return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
-
-}
-
-static void unusable_show_print(struct seq_file *m,
- pg_data_t *pgdat, struct zone *zone)
-{
- unsigned int order;
- int index;
- 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 = unusable_free_index(order, &info);
- seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
- }
-
- seq_putc(m, '\n');
-}
-
-/*
- * Display unusable free space index
- * XXX: Could be a lot more efficient, but it's not a critical path
- */
-static int unusable_show(struct seq_file *m, void *arg)
-{
- pg_data_t *pgdat = (pg_data_t *)arg;
-
- /* check memoryless node */
- if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
- return 0;
-
- walk_zones_in_node(m, pgdat, unusable_show_print);
-
- return 0;
-}
-
static void pagetypeinfo_showfree_print(struct seq_file *m,
pg_data_t *pgdat, struct zone *zone)
{
@@ -703,25 +644,6 @@ static const struct file_operations pagetypeinfo_file_ops = {
.release = seq_release,
};
-static const struct seq_operations unusable_op = {
- .start = frag_start,
- .next = frag_next,
- .stop = frag_stop,
- .show = unusable_show,
-};
-
-static int unusable_open(struct inode *inode, struct file *file)
-{
- return seq_open(file, &unusable_op);
-}
-
-static const struct file_operations unusable_file_ops = {
- .open = unusable_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = seq_release,
-};
-
#ifdef CONFIG_ZONE_DMA
#define TEXT_FOR_DMA(xx) xx "_dma",
#else
@@ -1066,10 +988,113 @@ 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("unusable_index", S_IRUGO, NULL, &unusable_file_ops);
proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
#endif
return 0;
}
module_init(setup_vmstat)
+
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+static struct dentry *extfrag_debug_root;
+
+/*
+ * Return an index indicating how much of the available free memory is
+ * unusable for an allocation of the requested size.
+ */
+static int unusable_free_index(unsigned int order,
+ struct contig_page_info *info)
+{
+ /* No free memory is interpreted as all free memory is unusable */
+ if (info->free_pages == 0)
+ return 1000;
+
+ /*
+ * Index should be a value between 0 and 1. Return a value to 3
+ * decimal places.
+ *
+ * 0 => no fragmentation
+ * 1 => high fragmentation
+ */
+ return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
+
+}
+
+static void unusable_show_print(struct seq_file *m,
+ pg_data_t *pgdat, struct zone *zone)
+{
+ unsigned int order;
+ int index;
+ 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 = unusable_free_index(order, &info);
+ seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
+ }
+
+ seq_putc(m, '\n');
+}
+
+/*
+ * Display unusable free space index
+ *
+ * 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.
+ */
+static int unusable_show(struct seq_file *m, void *arg)
+{
+ pg_data_t *pgdat = (pg_data_t *)arg;
+
+ /* check memoryless node */
+ if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
+ return 0;
+
+ walk_zones_in_node(m, pgdat, unusable_show_print);
+
+ return 0;
+}
+
+static const struct seq_operations unusable_op = {
+ .start = frag_start,
+ .next = frag_next,
+ .stop = frag_stop,
+ .show = unusable_show,
+};
+
+static int unusable_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &unusable_op);
+}
+
+static const struct file_operations unusable_file_ops = {
+ .open = unusable_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);
+ if (!extfrag_debug_root)
+ return -ENOMEM;
+
+ if (!debugfs_create_file("unusable_index", 0444,
+ extfrag_debug_root, NULL, &unusable_file_ops))
+ return -ENOMEM;
+
+ return 0;
+}
+
+module_init(extfrag_debug_init);
+#endif
--
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