Re: [PATCH 3/3] writeback: Reporting dirty thresholds in /proc/vmstat
From: Wu Fengguang <hidden>
Date: 2010-08-20 03:16:48
Also in:
linux-fsdevel, lkml
On Thu, Aug 19, 2010 at 01:57:27PM -0700, Michael Rubin wrote:
The kernel already exposes the desired thresholds in /proc/sys/vm with dirty_background_ratio and background_ratio. Instead the kernel may alter the number requested without giving the user any indication that is the case.
You mean the 5% lower bound in global_dirty_limits()? Let's rip it :)
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_pages_dirty_threshold 409111 nr_pages_dirty_background_threshold 818223
It's redundant to have _pages in the names. /proc/vmstat has the tradition to use nr_dirty instead of nr_pages_dirty. They do look like useful counters to export, especially when we do dynamic dirty limits in future.
quoted hunk ↗ jump to hunk
Signed-off-by: Michael Rubin <redacted> --- include/linux/mmzone.h | 2 ++ mm/vmstat.c | 8 ++++++++ 2 files changed, 10 insertions(+), 0 deletions(-)diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index f160481..7c4a3bf 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h@@ -114,6 +114,8 @@ enum zone_stat_item { #endif NR_PAGES_ENTERED_WRITEBACK, /* number of times pages enter writeback */ NR_FILE_PAGES_DIRTIED, /* number of times pages get dirtied */ + NR_PAGES_DIRTY_THRESHOLD, /* writeback threshold */ + NR_PAGES_DIRTY_BG_THRESHOLD,/* bg writeback threshold */
s/_PAGES//
quoted hunk ↗ jump to hunk
NR_VM_ZONE_STAT_ITEMS }; /*diff --git a/mm/vmstat.c b/mm/vmstat.c index e177a40..8b5bc78 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}};@@ -742,6 +743,8 @@ static const char * const vmstat_text[] = { #endif "nr_pages_entered_writeback", "nr_file_pages_dirtied", + "nr_pages_dirty_threshold", + "nr_pages_dirty_background_threshold",
s/_pages//
quoted hunk ↗ jump to hunk
#ifdef CONFIG_VM_EVENT_COUNTERS "pgpgin",@@ -901,6 +904,7 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos) #ifdef CONFIG_VM_EVENT_COUNTERS unsigned long *e; #endif + unsigned long dirty_thresh, dirty_bg_thresh; int i; if (*pos >= ARRAY_SIZE(vmstat_text))@@ -918,6 +922,10 @@ 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); + + get_dirty_limits(&dirty_thresh, &dirty_bg_thresh, NULL, NULL);
2.6.36-rc1 will need this:
global_dirty_limits(v + NR_DIRTY_THRESHOLD, v + NR_DIRTY_BG_THRESHOLD);
Thanks,
Fengguang
+ v[NR_PAGES_DIRTY_THRESHOLD] = dirty_thresh; + v[NR_PAGES_DIRTY_BG_THRESHOLD] = dirty_bg_thresh; #ifdef CONFIG_VM_EVENT_COUNTERS e = v + NR_VM_ZONE_STAT_ITEMS; all_vm_events(e); -- 1.7.1 -- 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>
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