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| author | Thomas Gleixner <tglx@linutronix.de> | 2016-12-15 11:44:28 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-01-14 11:29:43 +0100 |
| commit | 12907fbb1a691807bb0420a27126e15934cb7954 (patch) | |
| tree | 14ba1797a6e24d566513b368c59b13948130dc40 | |
| parent | cb42c9a3ebbbb23448c3f9a25417fae6309b1a92 (diff) | |
| download | linux-stable-12907fbb1a691807bb0420a27126e15934cb7954.tar.gz linux-stable-12907fbb1a691807bb0420a27126e15934cb7954.tar.bz2 linux-stable-12907fbb1a691807bb0420a27126e15934cb7954.zip | |
sched/clock, clocksource: Add optional cs::mark_unstable() method
PeterZ reported that we'd fail to mark the TSC unstable when the
clocksource watchdog finds it unsuitable.
Allow a clocksource to run a custom action when its being marked
unstable and hook up the TSC unstable code.
Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/kernel/tsc.c | 11 | ||||
| -rw-r--r-- | include/linux/clocksource.h | 3 | ||||
| -rw-r--r-- | kernel/time/clocksource.c | 4 |
3 files changed, 18 insertions, 0 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index be3a49ee0356..c8174c815d83 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1106,6 +1106,16 @@ static u64 read_tsc(struct clocksource *cs) return (u64)rdtsc_ordered(); } +static void tsc_cs_mark_unstable(struct clocksource *cs) +{ + if (tsc_unstable) + return; + tsc_unstable = 1; + clear_sched_clock_stable(); + disable_sched_clock_irqtime(); + pr_info("Marking TSC unstable due to clocksource watchdog\n"); +} + /* * .mask MUST be CLOCKSOURCE_MASK(64). See comment above read_tsc() */ @@ -1118,6 +1128,7 @@ static struct clocksource clocksource_tsc = { CLOCK_SOURCE_MUST_VERIFY, .archdata = { .vclock_mode = VCLOCK_TSC }, .resume = tsc_resume, + .mark_unstable = tsc_cs_mark_unstable, }; void mark_tsc_unstable(char *reason) diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index e315d04a2fd9..cfc75848a35d 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -62,6 +62,8 @@ struct module; * @archdata: arch-specific data * @suspend: suspend function for the clocksource, if necessary * @resume: resume function for the clocksource, if necessary + * @mark_unstable: Optional function to inform the clocksource driver that + * the watchdog marked the clocksource unstable * @owner: module reference, must be set by clocksource in modules * * Note: This struct is not used in hotpathes of the timekeeping code @@ -93,6 +95,7 @@ struct clocksource { unsigned long flags; void (*suspend)(struct clocksource *cs); void (*resume)(struct clocksource *cs); + void (*mark_unstable)(struct clocksource *cs); /* private: */ #ifdef CONFIG_CLOCKSOURCE_WATCHDOG diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 665985b0a89a..93621ae718d3 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -141,6 +141,10 @@ static void __clocksource_unstable(struct clocksource *cs) { cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG); cs->flags |= CLOCK_SOURCE_UNSTABLE; + + if (cs->mark_unstable) + cs->mark_unstable(cs); + if (finished_booting) schedule_work(&watchdog_work); } |