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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 /kernel/module.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 'kernel/module.c')
-rw-r--r--kernel/module.c14
1 files changed, 2 insertions, 12 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 1016b75b026a..0838246d8c94 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -723,16 +723,8 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
return -EFAULT;
name[MODULE_NAME_LEN-1] = '\0';
- /* Create stop_machine threads since free_module relies on
- * a non-failing stop_machine call. */
- ret = stop_machine_create();
- if (ret)
- return ret;
-
- if (mutex_lock_interruptible(&module_mutex) != 0) {
- ret = -EINTR;
- goto out_stop;
- }
+ if (mutex_lock_interruptible(&module_mutex) != 0)
+ return -EINTR;
mod = find_module(name);
if (!mod) {
@@ -792,8 +784,6 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
out:
mutex_unlock(&module_mutex);
-out_stop:
- stop_machine_destroy();
return ret;
}