path: root/kernel
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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-04-26 10:52:27 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-04-26 12:28:03 -0700
commit048a0e8f5e1d94c01a5fc70f5b2f2fd2f4527326 (patch)
tree3168a6b6b26942cc39113c434ae10f3f960b88d3 /kernel
parent6d8133919bac4270883b24328500875a49e71b36 (diff)
timer: Fix mod_timer_pinned() header comment
The mod_timer_pinned() header comment states that it prevents timers from being migrated to a different CPU. This is not the case, instead, it ensures that the timer is posted to the current CPU, but does nothing to prevent CPU-hotplug operations from migrating the timer. This commit therefore brings the comment header into alignment with reality. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/timer.c b/kernel/timer.c
index a297ffcf888..837c552fe83 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -861,7 +861,13 @@ EXPORT_SYMBOL(mod_timer);
* mod_timer_pinned() is a way to update the expire field of an
* active timer (if the timer is inactive it will be activated)
- * and not allow the timer to be migrated to a different CPU.
+ * and to ensure that the timer is scheduled on the current CPU.
+ *
+ * Note that this does not prevent the timer from being migrated
+ * when the current CPU goes offline. If this is a problem for
+ * you, use CPU-hotplug notifiers to handle it correctly, for
+ * example, cancelling the timer when the corresponding CPU goes
+ * offline.
* mod_timer_pinned(timer, expires) is equivalent to: