vmstats: add cond_resched() to refresh_cpu_vm_stats()

Dimitri Sivanich · torvalds · commit 468fd62ed909 · 2008-04-28T08:58:26.000-07:00
We've found that it can take quite a bit of time (100's of usec) to get
through the zone loop in refresh_cpu_vm_stats().

Adding a cond_resched() to allow other threads to run in the non-preemptive
case.

Signed-off-by: Dimitri Sivanich &lt;sivanich@sgi.com&gt;
Acked-by: Christoph Lameter &lt;clameter@sgi.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
diff --git a/mm/vmstat.c b/mm/vmstat.c
@@ -322,6 +322,7 @@ void refresh_cpu_vm_stats(int cpu)
 				p->expire = 3;
 #endif
 			}
+		cond_resched();
 #ifdef CONFIG_NUMA
 		/*
 		 * Deal with draining the remote pageset of this

Original file line number	Diff line number	Diff line change
`@@ -322,6 +322,7 @@ void refresh_cpu_vm_stats(int cpu)`
`322`	`322`	`p->expire = 3;`
`323`	`323`	`#endif`
`324`	`324`	`}`
	`325`	`+ cond_resched();`
`325`	`326`	`#ifdef CONFIG_NUMA`
`326`	`327`	`/*`
`327`	`328`	`* Deal with draining the remote pageset of this`