Commit-ID: 53370d2e8c0382e3e2aa76def93365ed674e7fc7
Gitweb: http://git.kernel.org/tip/53370d2e8c0382e3e2aa76def93365ed674e7fc7
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 10 Mar 2011 18:26:33 +0100
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 10 Mar 2011 19:15:58 +0100
hrtimer: Update hrtimer->state documentation
We changed some of the state bits and combinations thereof over time,
but never updated the documentation.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
include/linux/hrtimer.h | 16 +++++++++++-----
1 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 6bc1804..62f500c 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -54,11 +54,13 @@ enum hrtimer_restart {
* 0x00 inactive
* 0x01 enqueued into rbtree
* 0x02 callback function running
+ * 0x04 timer is migrated to another cpu
*
* Special cases:
* 0x03 callback function running and enqueued
* (was requeued on another CPU)
- * 0x09 timer was migrated on CPU hotunplug
+ * 0x05 timer was migrated on CPU hotunplug
+ *
* The "callback function running and enqueued" status is only possible on
* SMP. It happens for example when a posix timer expired and the callback
* queued a signal. Between dropping the lock which protects the posix timer
@@ -67,8 +69,11 @@ enum hrtimer_restart {
* as otherwise the timer could be removed before the softirq code finishes the
* the handling of the timer.
*
- * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state to
- * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario.
+ * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state
+ * to preserve the HRTIMER_STATE_CALLBACK in the above scenario. This
+ * also affects HRTIMER_STATE_MIGRATE where the preservation is not
+ * necessary. HRTIMER_STATE_MIGRATE is cleared after the timer is
+ * enqueued on the new cpu.
*
* All state transitions are protected by cpu_base->lock.
*/
@@ -376,8 +381,9 @@ extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
extern ktime_t hrtimer_get_next_event(void);
/*
- * A timer is active, when it is enqueued into the rbtree or the callback
- * function is running.
+ * A timer is active, when it is enqueued into the rbtree or the
+ * callback function is running or it's in the state of being migrated
+ * to another cpu.
*/
static inline int hrtimer_active(const struct hrtimer *timer)
{
--
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