* [PATCH 0/2] timers: Small fixes
@ 2022-04-05 19:17 Anna-Maria Behnsen
2022-04-05 19:17 ` [PATCH 1/2] timers: Initialize base::next_expiry_recalc during prepare cpu Anna-Maria Behnsen
2022-04-05 19:17 ` [PATCH 2/2] timers: Fix warning in __run_timers() Anna-Maria Behnsen
0 siblings, 2 replies; 7+ messages in thread
From: Anna-Maria Behnsen @ 2022-04-05 19:17 UTC (permalink / raw)
To: linux-kernel; +Cc: Thomas Gleixner, Peter Zijlstra, Frederic Weisbecker
This short queue fixes a missing initialization and a warning in timer
code.
Thanks,
Anna-Maria
Anna-Maria Behnsen (2):
timers: Initialize base::next_expiry_recalc during prepare cpu
timers: Fix warning in __run_timers()
kernel/time/timer.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
--
2.20.1
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH 1/2] timers: Initialize base::next_expiry_recalc during prepare cpu
2022-04-05 19:17 [PATCH 0/2] timers: Small fixes Anna-Maria Behnsen
@ 2022-04-05 19:17 ` Anna-Maria Behnsen
2022-04-05 21:51 ` Frederic Weisbecker
2022-04-09 20:22 ` [tip: timers/core] timers: Initialize base::next_expiry_recalc in timers_prepare_cpu() tip-bot2 for Anna-Maria Behnsen
2022-04-05 19:17 ` [PATCH 2/2] timers: Fix warning in __run_timers() Anna-Maria Behnsen
1 sibling, 2 replies; 7+ messages in thread
From: Anna-Maria Behnsen @ 2022-04-05 19:17 UTC (permalink / raw)
To: linux-kernel; +Cc: Thomas Gleixner, Peter Zijlstra, Frederic Weisbecker
When base::next_expiry_recalc is not initialized to false during cpu
bringup in HOTPLUG_CPU and is accidently true and no timer is queued in the
meantime, the loop through the wheel to find __next_timer_interrupt() might
be done for nothing.
Therefore initialize base::next_expiry_recalc to false in
timers_prepare_cpu().
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
---
kernel/time/timer.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 85f1021ad459..4af98e77cd78 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1950,6 +1950,7 @@ int timers_prepare_cpu(unsigned int cpu)
base = per_cpu_ptr(&timer_bases[b], cpu);
base->clk = jiffies;
base->next_expiry = base->clk + NEXT_TIMER_MAX_DELTA;
+ base->next_expiry_recalc = false;
base->timers_pending = false;
base->is_idle = false;
}
--
2.20.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] timers: Initialize base::next_expiry_recalc during prepare cpu
2022-04-05 19:17 ` [PATCH 1/2] timers: Initialize base::next_expiry_recalc during prepare cpu Anna-Maria Behnsen
@ 2022-04-05 21:51 ` Frederic Weisbecker
2022-04-09 20:22 ` [tip: timers/core] timers: Initialize base::next_expiry_recalc in timers_prepare_cpu() tip-bot2 for Anna-Maria Behnsen
1 sibling, 0 replies; 7+ messages in thread
From: Frederic Weisbecker @ 2022-04-05 21:51 UTC (permalink / raw)
To: Anna-Maria Behnsen; +Cc: linux-kernel, Thomas Gleixner, Peter Zijlstra
On Tue, Apr 05, 2022 at 09:17:31PM +0200, Anna-Maria Behnsen wrote:
> When base::next_expiry_recalc is not initialized to false during cpu
> bringup in HOTPLUG_CPU and is accidently true and no timer is queued in the
> meantime, the loop through the wheel to find __next_timer_interrupt() might
> be done for nothing.
>
> Therefore initialize base::next_expiry_recalc to false in
> timers_prepare_cpu().
>
> Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
^ permalink raw reply [flat|nested] 7+ messages in thread
* [tip: timers/core] timers: Initialize base::next_expiry_recalc in timers_prepare_cpu()
2022-04-05 19:17 ` [PATCH 1/2] timers: Initialize base::next_expiry_recalc during prepare cpu Anna-Maria Behnsen
2022-04-05 21:51 ` Frederic Weisbecker
@ 2022-04-09 20:22 ` tip-bot2 for Anna-Maria Behnsen
1 sibling, 0 replies; 7+ messages in thread
From: tip-bot2 for Anna-Maria Behnsen @ 2022-04-09 20:22 UTC (permalink / raw)
To: linux-tip-commits
Cc: Anna-Maria Behnsen, Thomas Gleixner, Frederic Weisbecker, x86,
linux-kernel
The following commit has been merged into the timers/core branch of tip:
Commit-ID: 2731aa7d65dbb31c6dad14347c37d522bb3bc7c6
Gitweb: https://git.kernel.org/tip/2731aa7d65dbb31c6dad14347c37d522bb3bc7c6
Author: Anna-Maria Behnsen <anna-maria@linutronix.de>
AuthorDate: Tue, 05 Apr 2022 21:17:31 +02:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sat, 09 Apr 2022 22:19:39 +02:00
timers: Initialize base::next_expiry_recalc in timers_prepare_cpu()
When base::next_expiry_recalc is not initialized to false during cpu
bringup in HOTPLUG_CPU and is accidently true and no timer is queued in the
meantime, the loop through the wheel to find __next_timer_interrupt() might
be done for nothing.
Therefore initialize base::next_expiry_recalc to false in
timers_prepare_cpu().
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20220405191732.7438-2-anna-maria@linutronix.de
---
kernel/time/timer.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 9dd2a39..204d6cd 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1953,6 +1953,7 @@ int timers_prepare_cpu(unsigned int cpu)
base = per_cpu_ptr(&timer_bases[b], cpu);
base->clk = jiffies;
base->next_expiry = base->clk + NEXT_TIMER_MAX_DELTA;
+ base->next_expiry_recalc = false;
base->timers_pending = false;
base->is_idle = false;
}
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/2] timers: Fix warning in __run_timers()
2022-04-05 19:17 [PATCH 0/2] timers: Small fixes Anna-Maria Behnsen
2022-04-05 19:17 ` [PATCH 1/2] timers: Initialize base::next_expiry_recalc during prepare cpu Anna-Maria Behnsen
@ 2022-04-05 19:17 ` Anna-Maria Behnsen
2022-04-05 21:43 ` Frederic Weisbecker
2022-04-09 20:22 ` [tip: timers/core] timers: Fix warning condition " tip-bot2 for Anna-Maria Behnsen
1 sibling, 2 replies; 7+ messages in thread
From: Anna-Maria Behnsen @ 2022-04-05 19:17 UTC (permalink / raw)
To: linux-kernel
Cc: Thomas Gleixner, Peter Zijlstra, Frederic Weisbecker, Johannes Berg
When the timer base is empty, base::next_expiry is set to base::clk +
NEXT_TIMER_MAX_DELTA and base::next_expiry_recalc is false. When no timer
is queued until jiffies reaches base::next_expiry value, the warning for
not finding any expired timer and base::next_expiry_recalc is false in
__run_timers() triggers.
To prevent triggering the warning in this valid scenario
base::timers_pending needs to be added to the warning condition.
Fixes: 31cd0e119d50 ("timers: Recalculate next timer interrupt only when necessary")
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
---
kernel/time/timer.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 4af98e77cd78..204d6cd83d0e 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1722,11 +1722,14 @@ static inline void __run_timers(struct timer_base *base)
time_after_eq(jiffies, base->next_expiry)) {
levels = collect_expired_timers(base, heads);
/*
- * The only possible reason for not finding any expired
- * timer at this clk is that all matching timers have been
- * dequeued.
+ * The two possible reasons for not finding any expired
+ * timer at this clk are that all matching timers have been
+ * dequeued or no timer has been queued since
+ * base::next_expiry was set to base::clk +
+ * NEXT_TIMER_MAX_DELTA.
*/
- WARN_ON_ONCE(!levels && !base->next_expiry_recalc);
+ WARN_ON_ONCE(!levels && !base->next_expiry_recalc
+ && base->timers_pending);
base->clk++;
base->next_expiry = __next_timer_interrupt(base);
--
2.20.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 2/2] timers: Fix warning in __run_timers()
2022-04-05 19:17 ` [PATCH 2/2] timers: Fix warning in __run_timers() Anna-Maria Behnsen
@ 2022-04-05 21:43 ` Frederic Weisbecker
2022-04-09 20:22 ` [tip: timers/core] timers: Fix warning condition " tip-bot2 for Anna-Maria Behnsen
1 sibling, 0 replies; 7+ messages in thread
From: Frederic Weisbecker @ 2022-04-05 21:43 UTC (permalink / raw)
To: Anna-Maria Behnsen
Cc: linux-kernel, Thomas Gleixner, Peter Zijlstra, Johannes Berg
On Tue, Apr 05, 2022 at 09:17:32PM +0200, Anna-Maria Behnsen wrote:
> When the timer base is empty, base::next_expiry is set to base::clk +
> NEXT_TIMER_MAX_DELTA and base::next_expiry_recalc is false. When no timer
> is queued until jiffies reaches base::next_expiry value, the warning for
> not finding any expired timer and base::next_expiry_recalc is false in
> __run_timers() triggers.
>
> To prevent triggering the warning in this valid scenario
> base::timers_pending needs to be added to the warning condition.
>
> Fixes: 31cd0e119d50 ("timers: Recalculate next timer interrupt only when necessary")
> Reported-by: Johannes Berg <johannes@sipsolutions.net>
> Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Thanks!
^ permalink raw reply [flat|nested] 7+ messages in thread
* [tip: timers/core] timers: Fix warning condition in __run_timers()
2022-04-05 19:17 ` [PATCH 2/2] timers: Fix warning in __run_timers() Anna-Maria Behnsen
2022-04-05 21:43 ` Frederic Weisbecker
@ 2022-04-09 20:22 ` tip-bot2 for Anna-Maria Behnsen
1 sibling, 0 replies; 7+ messages in thread
From: tip-bot2 for Anna-Maria Behnsen @ 2022-04-09 20:22 UTC (permalink / raw)
To: linux-tip-commits
Cc: Johannes Berg, Anna-Maria Behnsen, Thomas Gleixner,
Frederic Weisbecker, x86, linux-kernel
The following commit has been merged into the timers/core branch of tip:
Commit-ID: c54bc0fc84214b203f7a0ebfd1bd308ce2abe920
Gitweb: https://git.kernel.org/tip/c54bc0fc84214b203f7a0ebfd1bd308ce2abe920
Author: Anna-Maria Behnsen <anna-maria@linutronix.de>
AuthorDate: Tue, 05 Apr 2022 21:17:32 +02:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sat, 09 Apr 2022 22:17:47 +02:00
timers: Fix warning condition in __run_timers()
When the timer base is empty, base::next_expiry is set to base::clk +
NEXT_TIMER_MAX_DELTA and base::next_expiry_recalc is false. When no timer
is queued until jiffies reaches base::next_expiry value, the warning for
not finding any expired timer and base::next_expiry_recalc is false in
__run_timers() triggers.
To prevent triggering the warning in this valid scenario
base::timers_pending needs to be added to the warning condition.
Fixes: 31cd0e119d50 ("timers: Recalculate next timer interrupt only when necessary")
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20220405191732.7438-3-anna-maria@linutronix.de
---
kernel/time/timer.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 85f1021..9dd2a39 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1722,11 +1722,14 @@ static inline void __run_timers(struct timer_base *base)
time_after_eq(jiffies, base->next_expiry)) {
levels = collect_expired_timers(base, heads);
/*
- * The only possible reason for not finding any expired
- * timer at this clk is that all matching timers have been
- * dequeued.
+ * The two possible reasons for not finding any expired
+ * timer at this clk are that all matching timers have been
+ * dequeued or no timer has been queued since
+ * base::next_expiry was set to base::clk +
+ * NEXT_TIMER_MAX_DELTA.
*/
- WARN_ON_ONCE(!levels && !base->next_expiry_recalc);
+ WARN_ON_ONCE(!levels && !base->next_expiry_recalc
+ && base->timers_pending);
base->clk++;
base->next_expiry = __next_timer_interrupt(base);
^ permalink raw reply related [flat|nested] 7+ messages in thread
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Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2022-04-05 19:17 [PATCH 0/2] timers: Small fixes Anna-Maria Behnsen
2022-04-05 19:17 ` [PATCH 1/2] timers: Initialize base::next_expiry_recalc during prepare cpu Anna-Maria Behnsen
2022-04-05 21:51 ` Frederic Weisbecker
2022-04-09 20:22 ` [tip: timers/core] timers: Initialize base::next_expiry_recalc in timers_prepare_cpu() tip-bot2 for Anna-Maria Behnsen
2022-04-05 19:17 ` [PATCH 2/2] timers: Fix warning in __run_timers() Anna-Maria Behnsen
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2022-04-09 20:22 ` [tip: timers/core] timers: Fix warning condition " tip-bot2 for Anna-Maria Behnsen
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