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author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-25 17:40:56 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-25 17:40:56 +0200 |
commit | 5e686019df425a4fd8003ce7f6eaccbe537331d8 (patch) | |
tree | cc78762bc0fb471562ca1b5f745834a983020623 /arch | |
parent | Merge branch 'upstream/core' of git://git.kernel.org/pub/scm/linux/kernel/git... (diff) | |
parent | x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states (diff) | |
download | linux-5e686019df425a4fd8003ce7f6eaccbe537331d8.tar.xz linux-5e686019df425a4fd8003ce7f6eaccbe537331d8.zip |
Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states
sched: Fix rq->clock synchronization when migrating tasks
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/include/asm/tsc.h | 2 | ||||
-rw-r--r-- | arch/x86/kernel/tsc.c | 38 | ||||
-rw-r--r-- | arch/x86/power/cpu.c | 2 |
3 files changed, 42 insertions, 0 deletions
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h index c0427295e8f5..1ca132fc0d03 100644 --- a/arch/x86/include/asm/tsc.h +++ b/arch/x86/include/asm/tsc.h @@ -59,5 +59,7 @@ extern void check_tsc_sync_source(int cpu); extern void check_tsc_sync_target(void); extern int notsc_setup(char *); +extern void save_sched_clock_state(void); +extern void restore_sched_clock_state(void); #endif /* _ASM_X86_TSC_H */ diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index ce8e50239332..d632934cb638 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -626,6 +626,44 @@ static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu) local_irq_restore(flags); } +static unsigned long long cyc2ns_suspend; + +void save_sched_clock_state(void) +{ + if (!sched_clock_stable) + return; + + cyc2ns_suspend = sched_clock(); +} + +/* + * Even on processors with invariant TSC, TSC gets reset in some the + * ACPI system sleep states. And in some systems BIOS seem to reinit TSC to + * arbitrary value (still sync'd across cpu's) during resume from such sleep + * states. To cope up with this, recompute the cyc2ns_offset for each cpu so + * that sched_clock() continues from the point where it was left off during + * suspend. + */ +void restore_sched_clock_state(void) +{ + unsigned long long offset; + unsigned long flags; + int cpu; + + if (!sched_clock_stable) + return; + + local_irq_save(flags); + + get_cpu_var(cyc2ns_offset) = 0; + offset = cyc2ns_suspend - sched_clock(); + + for_each_possible_cpu(cpu) + per_cpu(cyc2ns_offset, cpu) = offset; + + local_irq_restore(flags); +} + #ifdef CONFIG_CPU_FREQ /* Frequency scaling support. Adjust the TSC based timer when the cpu frequency diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index e7e8c5f54956..87bb35e34ef1 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -113,6 +113,7 @@ static void __save_processor_state(struct saved_context *ctxt) void save_processor_state(void) { __save_processor_state(&saved_context); + save_sched_clock_state(); } #ifdef CONFIG_X86_32 EXPORT_SYMBOL(save_processor_state); @@ -229,6 +230,7 @@ static void __restore_processor_state(struct saved_context *ctxt) void restore_processor_state(void) { __restore_processor_state(&saved_context); + restore_sched_clock_state(); } #ifdef CONFIG_X86_32 EXPORT_SYMBOL(restore_processor_state); |