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authorMichael Rubin <mrubin@google.com>2010-10-26 14:21:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-26 16:52:06 -0700
commit79da826aee6a10902ef411bc65864bd02102fa83 (patch)
tree9cc3602fc53f889d9b7394663d4fdaa94d13a213 /mm/vmstat.c
parent2ac390370aac4aaa49cab17f328b478cbd5b3d8d (diff)
downloadvexpress-lsk-79da826aee6a10902ef411bc65864bd02102fa83.tar.gz
writeback: report dirty thresholds in /proc/vmstat
The kernel already exposes the user desired thresholds in /proc/sys/vm with dirty_background_ratio and background_ratio. But the kernel may alter the number requested without giving the user any indication that is the case. Knowing the actual ratios the kernel is honoring can help app developers understand how their buffered IO will be sent to the disk. $ grep threshold /proc/vmstat nr_dirty_threshold 409111 nr_dirty_background_threshold 818223 Signed-off-by: Michael Rubin <mrubin@google.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmstat.c')
-rw-r--r--mm/vmstat.c39
1 files changed, 25 insertions, 14 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 44e7ac0fdb6..baa4ab387db 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -17,6 +17,7 @@
#include <linux/vmstat.h>
#include <linux/sched.h>
#include <linux/math64.h>
+#include <linux/writeback.h>
#ifdef CONFIG_VM_EVENT_COUNTERS
DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
@@ -747,6 +748,8 @@ static const char * const vmstat_text[] = {
"nr_shmem",
"nr_dirtied",
"nr_written",
+ "nr_dirty_threshold",
+ "nr_dirty_background_threshold",
#ifdef CONFIG_NUMA
"numa_hit",
@@ -907,36 +910,44 @@ static const struct file_operations proc_zoneinfo_file_operations = {
.release = seq_release,
};
+enum writeback_stat_item {
+ NR_DIRTY_THRESHOLD,
+ NR_DIRTY_BG_THRESHOLD,
+ NR_VM_WRITEBACK_STAT_ITEMS,
+};
+
static void *vmstat_start(struct seq_file *m, loff_t *pos)
{
unsigned long *v;
-#ifdef CONFIG_VM_EVENT_COUNTERS
- unsigned long *e;
-#endif
- int i;
+ int i, stat_items_size;
if (*pos >= ARRAY_SIZE(vmstat_text))
return NULL;
+ stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
+ NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
#ifdef CONFIG_VM_EVENT_COUNTERS
- v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long)
- + sizeof(struct vm_event_state), GFP_KERNEL);
-#else
- v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long),
- GFP_KERNEL);
+ stat_items_size += sizeof(struct vm_event_state);
#endif
+
+ v = kmalloc(stat_items_size, GFP_KERNEL);
m->private = v;
if (!v)
return ERR_PTR(-ENOMEM);
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
v[i] = global_page_state(i);
+ v += NR_VM_ZONE_STAT_ITEMS;
+
+ global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
+ v + NR_DIRTY_THRESHOLD);
+ v += NR_VM_WRITEBACK_STAT_ITEMS;
+
#ifdef CONFIG_VM_EVENT_COUNTERS
- e = v + NR_VM_ZONE_STAT_ITEMS;
- all_vm_events(e);
- e[PGPGIN] /= 2; /* sectors -> kbytes */
- e[PGPGOUT] /= 2;
+ all_vm_events(v);
+ v[PGPGIN] /= 2; /* sectors -> kbytes */
+ v[PGPGOUT] /= 2;
#endif
- return v + *pos;
+ return m->private + *pos;
}
static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)