Commit-ID: f98823ac758ba1aa77c6e3f8ad4ef3ad84ee0a7c
Gitweb: http://git.kernel.org/tip/f98823ac758ba1aa77c6e3f8ad4ef3ad84ee0a7c
Author: Frederic Weisbecker <fweisbec@xxxxxxxxx>
AuthorDate: Wed, 27 Mar 2013 01:17:22 +0100
Committer: Frederic Weisbecker <fweisbec@xxxxxxxxx>
CommitDate: Fri, 19 Apr 2013 13:54:16 +0200
nohz: New option to default all CPUs in full dynticks range
Provide a new kernel config that defaults all CPUs to be part
of the full dynticks range, except the boot one for timekeeping.
This default setting is overriden by the nohz_full= boot option
if passed by the user.
This is helpful for those who don't need a finegrained range
of full dynticks CPU and also for automated testing.
Suggested-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Geoff Levand <geoff@xxxxxxxxxxxxx>
Cc: Gilad Ben Yossef <gilad@xxxxxxxxxxxxx>
Cc: Hakan Akkan <hakanakkan@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Kevin Hilman <khilman@xxxxxxxxxx>
Cc: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/time/Kconfig | 10 ++++++++++
kernel/time/tick-sched.c | 23 +++++++++++++++++++++--
2 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 358d601..99c3f13 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -128,6 +128,16 @@ config NO_HZ_FULL
endchoice
+config NO_HZ_FULL_ALL
+ bool "Full dynticks system on all CPUs by default"
+ depends on NO_HZ_FULL
+ help
+ If the user doesn't pass the nohz_full boot option to
+ define the range of full dynticks CPUs, consider that all
+ CPUs in the system are full dynticks by default.
+ Note the boot CPU will still be kept outside the range to
+ handle the timekeeping duty.
+
config NO_HZ
bool "Old Idle dynticks config"
depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index d71a5f2..a76e090 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -203,12 +203,31 @@ static int __cpuinit tick_nohz_cpu_down_callback(struct notifier_block *nfb,
*/
static char __initdata nohz_full_buf[NR_CPUS + 1];
+static int tick_nohz_init_all(void)
+{
+ int err = -1;
+
+#ifdef CONFIG_NO_HZ_FULL_ALL
+ if (!alloc_cpumask_var(&nohz_full_mask, GFP_KERNEL)) {
+ pr_err("NO_HZ: Can't allocate full dynticks cpumask\n");
+ return err;
+ }
+ err = 0;
+ cpumask_setall(nohz_full_mask);
+ cpumask_clear_cpu(smp_processor_id(), nohz_full_mask);
+ have_nohz_full_mask = true;
+#endif
+ return err;
+}
+
void __init tick_nohz_init(void)
{
int cpu;
- if (!have_nohz_full_mask)
- return;
+ if (!have_nohz_full_mask) {
+ if (tick_nohz_init_all() < 0)
+ return;
+ }
cpu_notifier(tick_nohz_cpu_down_callback, 0);
--
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