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| author | John Stultz <johnstul@us.ibm.com> | 2012-07-17 13:33:52 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-07-19 08:58:37 -0700 |
| commit | 62b787f886e2d96cc7c5428aeee05dbe32a9531b (patch) | |
| tree | efde1d722f2151d394f693da0790afd16cf6dc1a /include | |
| parent | c7e2580578671c4d19a1a83e6fdb2482cc136283 (diff) | |
| download | lwn-62b787f886e2d96cc7c5428aeee05dbe32a9531b.tar.gz lwn-62b787f886e2d96cc7c5428aeee05dbe32a9531b.zip | |
hrtimer: Provide clock_was_set_delayed()
This is a backport of f55a6faa384304c89cfef162768e88374d3312cb
clock_was_set() cannot be called from hard interrupt context because
it calls on_each_cpu().
For fixing the widely reported leap seconds issue it is necessary to
call it from hard interrupt context, i.e. the timer tick code, which
does the timekeeping updates.
Provide a new function which denotes it in the hrtimer cpu base
structure of the cpu on which it is called and raise the hrtimer
softirq. We then execute the clock_was_set() notificiation from
softirq context in run_hrtimer_softirq(). The hrtimer softirq is
rarely used, so polling the flag there is not a performance issue.
[ tglx: Made it depend on CONFIG_HIGH_RES_TIMERS. We really should get
rid of all this ifdeffery ASAP ]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Reported-by: Jan Engelhardt <jengelh@inai.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1341960205-56738-2-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/hrtimer.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index fd0dc30c9f15..c9ec9400ee5b 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -165,6 +165,7 @@ enum hrtimer_base_type { * @lock: lock protecting the base and associated clock bases * and timers * @active_bases: Bitfield to mark bases with active timers + * @clock_was_set: Indicates that clock was set from irq context. * @expires_next: absolute time of the next event which was scheduled * via clock_set_next_event() * @hres_active: State of high resolution mode @@ -177,7 +178,8 @@ enum hrtimer_base_type { */ struct hrtimer_cpu_base { raw_spinlock_t lock; - unsigned long active_bases; + unsigned int active_bases; + unsigned int clock_was_set; #ifdef CONFIG_HIGH_RES_TIMERS ktime_t expires_next; int hres_active; @@ -286,6 +288,8 @@ extern void hrtimer_peek_ahead_timers(void); # define MONOTONIC_RES_NSEC HIGH_RES_NSEC # define KTIME_MONOTONIC_RES KTIME_HIGH_RES +extern void clock_was_set_delayed(void); + #else # define MONOTONIC_RES_NSEC LOW_RES_NSEC @@ -306,6 +310,9 @@ static inline int hrtimer_is_hres_active(struct hrtimer *timer) { return 0; } + +static inline void clock_was_set_delayed(void) { } + #endif extern void clock_was_set(void); |