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Currently, kswapd() function has deeper nest and it slightly harder to
read. cleanup it.
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
mm/vmscan.c | 71 +++++++++++++++++++++++++++++++---------------------------
1 files changed, 38 insertions(+), 33 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8cc90d5..82ffe5f 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2364,6 +2364,42 @@ out:
return sc.nr_reclaimed;
}
+void kswapd_try_to_sleep(pg_data_t *pgdat, int order)
+{
+ long remaining = 0;
+ DEFINE_WAIT(wait);
+
+ if (freezing(current) || kthread_should_stop())
+ return;
+
+ prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
+
+ /* Try to sleep for a short interval */
+ if (!sleeping_prematurely(pgdat, order, remaining)) {
+ remaining = schedule_timeout(HZ/10);
+ finish_wait(&pgdat->kswapd_wait, &wait);
+ prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
+ }
+
+ /*
+ * After a short sleep, check if it was a
+ * premature sleep. If not, then go fully
+ * to sleep until explicitly woken up
+ */
+ if (!sleeping_prematurely(pgdat, order, remaining)) {
+ trace_mm_vmscan_kswapd_sleep(pgdat->node_id);
+ set_pgdat_percpu_threshold(pgdat, calculate_normal_threshold);
+ schedule();
+ set_pgdat_percpu_threshold(pgdat, calculate_pressure_threshold);
+ } else {
+ if (remaining)
+ count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY);
+ else
+ count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY);
+ }
+ finish_wait(&pgdat->kswapd_wait, &wait);
+}
+
/*
* The background pageout daemon, started as a kernel thread
* from the init process.
@@ -2382,7 +2418,7 @@ static int kswapd(void *p)
unsigned long order;
pg_data_t *pgdat = (pg_data_t*)p;
struct task_struct *tsk = current;
- DEFINE_WAIT(wait);
+
struct reclaim_state reclaim_state = {
.reclaimed_slab = 0,
};
@@ -2414,7 +2450,6 @@ static int kswapd(void *p)
unsigned long new_order;
int ...Shouldn't this be static void kswapd_try_to_sleep(pg_data_t *pgdat, int order) ?? -- Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/ Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please. --
Right. thank you. I'll respin. --
Done.
From a29f0f5b780170fc26eb9210df03ed974aad8362 Mon Sep 17 00:00:00 2001
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Date: Fri, 3 Dec 2010 10:48:41 +0900
Subject: [PATCH] factor out kswapd sleeping logic from kswapd()
Currently, kswapd() function has deeper nest and it slightly harder to
read. cleanup it.
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
mm/vmscan.c | 71 +++++++++++++++++++++++++++++++---------------------------
1 files changed, 38 insertions(+), 33 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8cc90d5..3ee33a8 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2364,6 +2364,42 @@ out:
return sc.nr_reclaimed;
}
+static void kswapd_try_to_sleep(pg_data_t *pgdat, int order)
+{
+ long remaining = 0;
+ DEFINE_WAIT(wait);
+
+ if (freezing(current) || kthread_should_stop())
+ return;
+
+ prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
+
+ /* Try to sleep for a short interval */
+ if (!sleeping_prematurely(pgdat, order, remaining)) {
+ remaining = schedule_timeout(HZ/10);
+ finish_wait(&pgdat->kswapd_wait, &wait);
+ prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
+ }
+
+ /*
+ * After a short sleep, check if it was a
+ * premature sleep. If not, then go fully
+ * to sleep until explicitly woken up
+ */
+ if (!sleeping_prematurely(pgdat, order, remaining)) {
+ trace_mm_vmscan_kswapd_sleep(pgdat->node_id);
+ set_pgdat_percpu_threshold(pgdat, calculate_normal_threshold);
+ schedule();
+ set_pgdat_percpu_threshold(pgdat, calculate_pressure_threshold);
+ } else {
+ if (remaining)
+ count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY);
+ else
+ count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY);
+ }
+ finish_wait(&pgdat->kswapd_wait, &wait);
+}
+
/*
* The background pageout daemon, started as a kernel thread
* from the init process.
@@ -2382,7 +2418,7 @@ static int kswapd(void *p)
unsigned long order;
...I posted a patch adding a comment on why set_pgdat_percpu_threshold() is called. I do not believe it has been picked up by Andrew but it if is, the patches will conflict. The resolution will be obvious but you may need to respin this patch if the comment patch gets picked up in mmotm. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab --
OK, I've rebased the patch on top your comment patch.
From 1bd232713d55f033676f80cc7451ff83d4483884 Mon Sep 17 00:00:00 2001
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Date: Mon, 6 Dec 2010 20:44:27 +0900
Subject: [PATCH] factor out kswapd sleeping logic from kswapd()
Currently, kswapd() function has deeper nest and it slightly harder to
read. cleanup it.
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
mm/vmscan.c | 92 +++++++++++++++++++++++++++++-----------------------------
1 files changed, 46 insertions(+), 46 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 33994b7..cd07b97 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2364,6 +2364,50 @@ out:
return sc.nr_reclaimed;
}
+static void kswapd_try_to_sleep(pg_data_t *pgdat, int order)
+{
+ long remaining = 0;
+ DEFINE_WAIT(wait);
+
+ if (freezing(current) || kthread_should_stop())
+ return;
+
+ prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
+
+ /* Try to sleep for a short interval */
+ if (!sleeping_prematurely(pgdat, order, remaining)) {
+ remaining = schedule_timeout(HZ/10);
+ finish_wait(&pgdat->kswapd_wait, &wait);
+ prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
+ }
+
+ /*
+ * After a short sleep, check if it was a premature sleep. If not, then
+ * go fully to sleep until explicitly woken up.
+ */
+ if (!sleeping_prematurely(pgdat, order, remaining)) {
+ trace_mm_vmscan_kswapd_sleep(pgdat->node_id);
+
+ /*
+ * vmstat counters are not perfectly accurate and the estimated
+ * value for counters such as NR_FREE_PAGES can deviate from the
+ * true value by nr_online_cpus * threshold. To avoid the zone
+ * watermarks being breached while under pressure, we reduce the
+ * per-cpu vmstat threshold while kswapd is awake and restore
+ * them before going back to sleep.
+ */
+ set_pgdat_percpu_threshold(pgdat, ...Acked-by: Mel Gorman <mel@csn.ul.ie> -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab --
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