From: Viresh Kumar <viresh.kumar@linaro.org>
To: tglx@linutronix.de
Cc: linaro-kernel@lists.linaro.org, linaro-networking@linaro.org,
linux-kernel@vger.kernel.org, fweisbec@gmail.com,
arvind.chauhan@arm.com, Viresh Kumar <viresh.kumar@linaro.org>
Subject: [PATCH Resend] hrtimer: call switch_hrtimer_base() after setting new expiry time
Date: Mon, 12 May 2014 13:42:29 +0530 [thread overview]
Message-ID: <81999e148745fc51bbcd0615823fbab9b2e87e23.1399882253.git.viresh.kumar@linaro.org> (raw)
In switch_hrtimer_base() we are calling hrtimer_check_target() which guarantees
this:
/*
* With HIGHRES=y we do not migrate the timer when it is expiring
* before the next event on the target cpu because we cannot reprogram
* the target cpu hardware and we would cause it to fire late.
*
* Called with cpu_base->lock of target cpu held.
*/
But switch_hrtimer_base() is only called from one place, i.e.
__hrtimer_start_range_ns() and at that point (where we call
switch_hrtimer_base()) expiration time is not yet known as we call this routine
later: hrtimer_set_expires_range_ns().
To fix this, we need to find the updated expiry time before calling
switch_hrtimer_base().
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
Rebased over: v3.15-rc5
kernel/hrtimer.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 6b715c0..e0501fe 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -990,11 +990,8 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
/* Remove an active timer from the queue: */
ret = remove_hrtimer(timer, base);
- /* Switch the timer base, if necessary: */
- new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
-
if (mode & HRTIMER_MODE_REL) {
- tim = ktime_add_safe(tim, new_base->get_time());
+ tim = ktime_add_safe(tim, base->get_time());
/*
* CONFIG_TIME_LOW_RES is a temporary way for architectures
* to signal that they simply return xtime in
@@ -1009,6 +1006,9 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
hrtimer_set_expires_range_ns(timer, tim, delta_ns);
+ /* Switch the timer base, if necessary: */
+ new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
+
timer_stats_hrtimer_set_start_info(timer);
leftmost = enqueue_hrtimer(timer, new_base);
--
2.0.0.rc2
next reply other threads:[~2014-05-12 8:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-12 8:12 Viresh Kumar [this message]
2014-05-12 8:51 ` [tip:timers/urgent] hrtimer: Set expiry time before switch_hrtimer_base() tip-bot for Viresh Kumar
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