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| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2010-11-23 16:11:40 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2010-12-13 16:23:56 -0800 |
| commit | 3fb82d56ad003e804923185316236f26b30dfdd5 (patch) | |
| tree | 3ee08bef7cdc0f0ed3b69be5609b53c44299a229 /kernel/cpu.c | |
| parent | cf7d7e5a1980d1116ee152d25dac382b112b9c17 (diff) | |
| download | linux-3fb82d56ad003e804923185316236f26b30dfdd5.tar.gz linux-3fb82d56ad003e804923185316236f26b30dfdd5.tar.bz2 linux-3fb82d56ad003e804923185316236f26b30dfdd5.zip | |
x86, suspend: Avoid unnecessary smp alternatives switch during suspend/resume
During suspend, we disable all the non boot cpus. And during resume we bring
them all back again. So no need to do alternatives_smp_switch() in between.
On my core 2 based laptop, this speeds up the suspend path by 15msec and the
resume path by 5 msec (suspend/resume speed up differences can be attributed
to the different P-states that the cpu is in during suspend/resume).
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1290557500.4946.8.camel@sbsiddha-MOBL3.sc.intel.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index f6e726f18491..8ccc182069ec 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -386,6 +386,14 @@ out: #ifdef CONFIG_PM_SLEEP_SMP static cpumask_var_t frozen_cpus; +void __weak arch_disable_nonboot_cpus_begin(void) +{ +} + +void __weak arch_disable_nonboot_cpus_end(void) +{ +} + int disable_nonboot_cpus(void) { int cpu, first_cpu, error = 0; @@ -397,6 +405,7 @@ int disable_nonboot_cpus(void) * with the userspace trying to use the CPU hotplug at the same time */ cpumask_clear(frozen_cpus); + arch_disable_nonboot_cpus_begin(); printk("Disabling non-boot CPUs ...\n"); for_each_online_cpu(cpu) { @@ -412,6 +421,8 @@ int disable_nonboot_cpus(void) } } + arch_disable_nonboot_cpus_end(); + if (!error) { BUG_ON(num_online_cpus() > 1); /* Make sure the CPUs won't be enabled by someone else */ |