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author | Ingo Molnar <mingo@elte.hu> | 2008-06-16 11:15:58 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-06-16 11:15:58 +0200 |
commit | e765ee90da62535ac7d7a97f2464f9646539d683 (patch) | |
tree | 7a9cecce5aab958938e9a3bf46c2302d6af1958c /arch/x86/lib | |
parent | a4500b84c51645bbc86be3ca84f2252b7ada060f (diff) | |
parent | 066519068ad2fbe98c7f45552b1f592903a9c8c8 (diff) | |
download | linux-e765ee90da62535ac7d7a97f2464f9646539d683.tar.gz linux-e765ee90da62535ac7d7a97f2464f9646539d683.tar.bz2 linux-e765ee90da62535ac7d7a97f2464f9646539d683.zip |
Merge branch 'linus' into tracing/ftrace
Diffstat (limited to 'arch/x86/lib')
-rw-r--r-- | arch/x86/lib/delay_32.c | 31 | ||||
-rw-r--r-- | arch/x86/lib/delay_64.c | 30 |
2 files changed, 53 insertions, 8 deletions
diff --git a/arch/x86/lib/delay_32.c b/arch/x86/lib/delay_32.c index 4535e6d147ad..d710f2d167bb 100644 --- a/arch/x86/lib/delay_32.c +++ b/arch/x86/lib/delay_32.c @@ -44,13 +44,36 @@ static void delay_loop(unsigned long loops) static void delay_tsc(unsigned long loops) { unsigned long bclock, now; + int cpu; - preempt_disable(); /* TSC's are per-cpu */ + preempt_disable(); + cpu = smp_processor_id(); rdtscl(bclock); - do { - rep_nop(); + for (;;) { rdtscl(now); - } while ((now-bclock) < loops); + if ((now - bclock) >= loops) + break; + + /* Allow RT tasks to run */ + preempt_enable(); + rep_nop(); + preempt_disable(); + + /* + * It is possible that we moved to another CPU, and + * since TSC's are per-cpu we need to calculate + * that. The delay must guarantee that we wait "at + * least" the amount of time. Being moved to another + * CPU could make the wait longer but we just need to + * make sure we waited long enough. Rebalance the + * counter for this CPU. + */ + if (unlikely(cpu != smp_processor_id())) { + loops -= (now - bclock); + cpu = smp_processor_id(); + rdtscl(bclock); + } + } preempt_enable(); } diff --git a/arch/x86/lib/delay_64.c b/arch/x86/lib/delay_64.c index bbc610518516..4c441be92641 100644 --- a/arch/x86/lib/delay_64.c +++ b/arch/x86/lib/delay_64.c @@ -31,14 +31,36 @@ int __devinit read_current_timer(unsigned long *timer_value) void __delay(unsigned long loops) { unsigned bclock, now; + int cpu; - preempt_disable(); /* TSC's are pre-cpu */ + preempt_disable(); + cpu = smp_processor_id(); rdtscl(bclock); - do { - rep_nop(); + for (;;) { rdtscl(now); + if ((now - bclock) >= loops) + break; + + /* Allow RT tasks to run */ + preempt_enable(); + rep_nop(); + preempt_disable(); + + /* + * It is possible that we moved to another CPU, and + * since TSC's are per-cpu we need to calculate + * that. The delay must guarantee that we wait "at + * least" the amount of time. Being moved to another + * CPU could make the wait longer but we just need to + * make sure we waited long enough. Rebalance the + * counter for this CPU. + */ + if (unlikely(cpu != smp_processor_id())) { + loops -= (now - bclock); + cpu = smp_processor_id(); + rdtscl(bclock); + } } - while ((now-bclock) < loops); preempt_enable(); } EXPORT_SYMBOL(__delay); |