[PATCH 4/4] writeback: Reporting dirty thresholds in /proc/vmstat

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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@xxxxxxxxxx>
---
 include/linux/mmzone.h |    3 +++
 mm/vmstat.c            |    5 +++++
 2 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index fe4e6dd..c2243d0 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -106,6 +106,9 @@ enum zone_stat_item {
 	NR_SHMEM,		/* shmem pages (included tmpfs/GEM pages) */
 	NR_FILE_PAGES_DIRTIED,	/* number of times pages get dirtied */
 	NR_PAGES_ENTERED_WRITEBACK, /* number of times pages enter writeback */
+	NR_DIRTY_THRESHOLD,	/* writeback threshold */
+	NR_DIRTY_BG_THRESHOLD,	/* bg writeback threshold */
+
 #ifdef CONFIG_NUMA
 	NUMA_HIT,		/* allocated in intended node */
 	NUMA_MISS,		/* allocated in non intended node */
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 073a496..c755d71 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}};
@@ -734,6 +735,8 @@ static const char * const vmstat_text[] = {
 	"nr_shmem",
 	"nr_dirtied",
 	"nr_entered_writeback",
+	"nr_dirty_threshold",
+	"nr_dirty_background_threshold",
 
 #ifdef CONFIG_NUMA
 	"numa_hit",
@@ -917,6 +920,8 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
 		return ERR_PTR(-ENOMEM);
 	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 		v[i] = global_page_state(i);
+
+	global_dirty_limits(v + NR_DIRTY_THRESHOLD, v + NR_DIRTY_BG_THRESHOLD);
 #ifdef CONFIG_VM_EVENT_COUNTERS
 	e = v + NR_VM_ZONE_STAT_ITEMS;
 	all_vm_events(e);
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux