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authorTejun Heo <tj@kernel.org>2010-05-06 12:49:20 -0400
committerTejun Heo <tj@kernel.org>2010-05-06 12:49:20 -0400
commit3fc1f1e27a5b807791d72e5d992aa33b668a6626 (patch)
tree396c2f49909c506c3ad53fd6a9bdddf6c24f7860 /drivers
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 'drivers')
-rw-r--r--drivers/xen/manage.c14
1 files changed, 2 insertions, 12 deletions
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index 2ac4440e7b08..8943b8ccee1a 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -80,12 +80,6 @@ static void do_suspend(void)
80 80
81 shutting_down = SHUTDOWN_SUSPEND; 81 shutting_down = SHUTDOWN_SUSPEND;
82 82
83 err = stop_machine_create();
84 if (err) {
85 printk(KERN_ERR "xen suspend: failed to setup stop_machine %d\n", err);
86 goto out;
87 }
88
89#ifdef CONFIG_PREEMPT 83#ifdef CONFIG_PREEMPT
90 /* If the kernel is preemptible, we need to freeze all the processes 84 /* If the kernel is preemptible, we need to freeze all the processes
91 to prevent them from being in the middle of a pagetable update 85 to prevent them from being in the middle of a pagetable update
@@ -93,7 +87,7 @@ static void do_suspend(void)
93 err = freeze_processes(); 87 err = freeze_processes();
94 if (err) { 88 if (err) {
95 printk(KERN_ERR "xen suspend: freeze failed %d\n", err); 89 printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
96 goto out_destroy_sm; 90 goto out;
97 } 91 }
98#endif 92#endif
99 93
@@ -136,12 +130,8 @@ out_resume:
136out_thaw: 130out_thaw:
137#ifdef CONFIG_PREEMPT 131#ifdef CONFIG_PREEMPT
138 thaw_processes(); 132 thaw_processes();
139
140out_destroy_sm:
141#endif
142 stop_machine_destroy();
143
144out: 133out:
134#endif
145 shutting_down = SHUTDOWN_INVALID; 135 shutting_down = SHUTDOWN_INVALID;
146} 136}
147#endif /* CONFIG_PM_SLEEP */ 137#endif /* CONFIG_PM_SLEEP */