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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2012-12-18 18:24:35 +0100 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2013-03-21 15:55:45 +0100 |
| commit | a382bf934449ddeb625167537ae81daa0211b477 (patch) | |
| tree | 6ee5becb6b01c952d8fb7d561e10c1e2967d7b99 /kernel/time/tick-broadcast.c | |
| parent | a831881be220358a1d28c5d95d69449fb6d623ca (diff) | |
| download | linux-a382bf934449ddeb625167537ae81daa0211b477.tar.gz linux-a382bf934449ddeb625167537ae81daa0211b477.tar.bz2 linux-a382bf934449ddeb625167537ae81daa0211b477.zip | |
nohz: Assign timekeeping duty to a CPU outside the full dynticks range
This way the full nohz CPUs can safely run with the tick
stopped with a guarantee that somebody else is taking
care of the jiffies and GTOD progression.
Once the duty is attributed to a CPU, it won't change. Also that
CPU can't enter into dyntick idle mode or be hot unplugged.
This may later be improved from a power consumption POV. At
least we should be able to share the duty amongst all CPUs
outside the full dynticks range. Then the duty could even be
shared with full dynticks CPUs when those can't stop their
tick for any reason.
But let's start with that very simple approach first.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
[fix have_nohz_full_mask offcase]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/time/tick-broadcast.c')
| -rw-r--r-- | kernel/time/tick-broadcast.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 2fb8cb88df8d..8a6875cc1879 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -573,7 +573,8 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc) bc->event_handler = tick_handle_oneshot_broadcast; /* Take the do_timer update */ - tick_do_timer_cpu = cpu; + if (!tick_nohz_extended_cpu(cpu)) + tick_do_timer_cpu = cpu; /* * We must be careful here. There might be other CPUs |