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| author | Steven Rostedt <rostedt@goodmis.org> | 2013-05-10 17:12:28 -0400 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2013-06-20 01:15:51 +0200 |
| commit | e12d0271774fea9fddf1e2a7952a0bffb2ee8e8b (patch) | |
| tree | 6bd6a506cd535836ec419055cc4c20f0a6648224 /kernel | |
| parent | 7d132055814ef17a6c7b69f342244c410a5e000f (diff) | |
| download | blackbird-op-linux-e12d0271774fea9fddf1e2a7952a0bffb2ee8e8b.tar.gz blackbird-op-linux-e12d0271774fea9fddf1e2a7952a0bffb2ee8e8b.zip | |
nohz: Warn if the machine can not perform nohz_full
If the user configures NO_HZ_FULL and defines nohz_full=XXX on the
kernel command line, or enables NO_HZ_FULL_ALL, but nohz fails
due to the machine having a unstable clock, warn about it.
We do not want users thinking that they are getting the benefit
of nohz when their machine can not support it.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/tick-sched.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index f4208138fbf4..d87d22cb9bf2 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -178,6 +178,11 @@ static bool can_stop_full_tick(void) */ if (!sched_clock_stable) { trace_tick_stop(0, "unstable sched clock\n"); + /* + * Don't allow the user to think they can get + * full NO_HZ with this machine. + */ + WARN_ONCE(1, "NO_HZ FULL will not work with unstable sched clock"); return false; } #endif |
