From: Christoph Lameter Date: Fri, 11 May 2007 05:22:21 +0000 (-0700) Subject: VM statistics: Make timer deferrable X-Git-Url: http://drtracing.org/?a=commitdiff_plain;ds=sidebyside;h=39bf6270f524bbe2682b56f2a979703abf937dd1;hp=45222b9e02fb282eb0a8007a3d992dd229ec2410;p=deliverable%2Flinux.git VM statistics: Make timer deferrable VM statistics updates do not matter if the kernel is in idle powersaving mode. So allow the timer to be deferred. It would be better though if we could switch the timer between deferrable and nondeferrable based on differentials present. The timer would start out nondeferrable and if we find that there were no updates in the last statistics interval then we would switch the timer to deferrable. If the timer later finds again that there are differentials then go to nondeferrable again. And yet another way would be to run the timer shortly before going to idle? The solution here means that the VM counters may be slightly off during idle since differentials may be still pending while the timer is deferred. Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/vmstat.c b/mm/vmstat.c index 9832d9a41d8c..8faf27e5aa98 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -698,7 +698,7 @@ static void __devinit start_cpu_timer(int cpu) { struct delayed_work *vmstat_work = &per_cpu(vmstat_work, cpu); - INIT_DELAYED_WORK(vmstat_work, vmstat_update); + INIT_DELAYED_WORK_DEFERRABLE(vmstat_work, vmstat_update); schedule_delayed_work_on(cpu, vmstat_work, HZ + cpu); }