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authorTejun Heo <tj@kernel.org>2010-05-06 18:49:20 +0200
committerTejun Heo <tj@kernel.org>2010-05-06 18:49:20 +0200
commit3fc1f1e27a5b807791d72e5d992aa33b668a6626 (patch)
tree396c2f49909c506c3ad53fd6a9bdddf6c24f7860 /arch/s390/kernel/time.c
parent1142d810298e694754498dbb4983fcb6cb7fd884 (diff)
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 <tj@kernel.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Dimitri Sivanich <sivanich@sgi.com>
Diffstat (limited to 'arch/s390/kernel/time.c')
-rw-r--r--arch/s390/kernel/time.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index fba6dec156bf..03d96569f187 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();
}
/*