diff options
| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2010-11-24 01:11:40 +0100 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2010-12-14 01:23:56 +0100 |
| commit | 3fb82d56ad003e804923185316236f26b30dfdd5 (patch) | |
| tree | 3ee08bef7cdc0f0ed3b69be5609b53c44299a229 /arch | |
| parent | Linux 2.6.37-rc5 (diff) | |
| download | linux-3fb82d56ad003e804923185316236f26b30dfdd5.tar.xz 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 'arch')
| -rw-r--r-- | arch/x86/include/asm/alternative.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/alternative.c | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 14 |
3 files changed, 17 insertions, 1 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index 76561d20ea2f..01171f6c2c37 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -66,6 +66,7 @@ extern void alternatives_smp_module_add(struct module *mod, char *name, extern void alternatives_smp_module_del(struct module *mod); extern void alternatives_smp_switch(int smp); extern int alternatives_text_reserved(void *start, void *end); +extern bool skip_smp_alternatives; #else static inline void alternatives_smp_module_add(struct module *mod, char *name, void *locks, void *locks_end, diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 5079f24c955a..9f98eb400fef 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -353,6 +353,7 @@ void __init_or_module alternatives_smp_module_del(struct module *mod) mutex_unlock(&smp_alt); } +bool skip_smp_alternatives; void alternatives_smp_switch(int smp) { struct smp_alt_module *mod; @@ -368,7 +369,7 @@ void alternatives_smp_switch(int smp) printk("lockdep: fixing up alternatives.\n"); #endif - if (noreplace_smp || smp_alt_once) + if (noreplace_smp || smp_alt_once || skip_smp_alternatives) return; BUG_ON(!smp && (num_online_cpus() > 1)); diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 083e99d1b7df..837c81e99edf 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1166,6 +1166,20 @@ out: preempt_enable(); } +void arch_disable_nonboot_cpus_begin(void) +{ + /* + * Avoid the smp alternatives switch during the disable_nonboot_cpus(). + * In the suspend path, we will be back in the SMP mode shortly anyways. + */ + skip_smp_alternatives = true; +} + +void arch_disable_nonboot_cpus_end(void) +{ + skip_smp_alternatives = false; +} + void arch_enable_nonboot_cpus_begin(void) { set_mtrr_aps_delayed_init(); |