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authorThomas Gleixner <tglx@linutronix.de>2016-12-15 13:44:28 +0300
committerIngo Molnar <mingo@kernel.org>2017-01-14 13:29:43 +0300
commit12907fbb1a691807bb0420a27126e15934cb7954 (patch)
tree14ba1797a6e24d566513b368c59b13948130dc40 /arch/x86/kernel/tsc.c
parentcb42c9a3ebbbb23448c3f9a25417fae6309b1a92 (diff)
downloadlinux-12907fbb1a691807bb0420a27126e15934cb7954.tar.xz
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>
Diffstat (limited to 'arch/x86/kernel/tsc.c')
-rw-r--r--arch/x86/kernel/tsc.c11
1 files changed, 11 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)