From 3fc1f1e27a5b807791d72e5d992aa33b668a6626 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 6 May 2010 18:49:20 +0200 Subject: stop_machine: reimplement using cpu_stop Reimplement stop_machine using cpu_stop. As cpu stoppers are guaranteed to be available for all online cpus, stop_machine_create/destroy() are no longer necessary and removed. With resource management and synchronization handled by cpu_stop, the new implementation is much simpler. Asking the cpu_stop to execute the stop_cpu() state machine on all online cpus with cpu hotplug disabled is enough. stop_machine itself doesn't need to manage any global resources anymore, so all per-instance information is rolled into struct stop_machine_data and the mutex and all static data variables are removed. The previous implementation created and destroyed RT workqueues as necessary which made stop_machine() calls highly expensive on very large machines. According to Dimitri Sivanich, preventing the dynamic creation/destruction makes booting faster more than twice on very large machines. cpu_stop resources are preallocated for all online cpus and should have the same effect. Signed-off-by: Tejun Heo Acked-by: Rusty Russell Acked-by: Peter Zijlstra Cc: Oleg Nesterov Cc: Dimitri Sivanich --- arch/s390/kernel/time.c | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/s390/kernel') diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c index fba6dec..03d9656 100644 --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -390,7 +390,6 @@ static void __init time_init_wq(void) if (time_sync_wq) return; time_sync_wq = create_singlethread_workqueue("timesync"); - stop_machine_create(); } /* -- cgit v1.1