diff options
Diffstat (limited to 'arch/x86/kernel/tsc_sync.c')
| -rw-r--r-- | arch/x86/kernel/tsc_sync.c | 45 |
1 files changed, 43 insertions, 2 deletions
diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c index 32a818764e03..9452dc9664b5 100644 --- a/arch/x86/kernel/tsc_sync.c +++ b/arch/x86/kernel/tsc_sync.c @@ -30,6 +30,7 @@ struct tsc_adjust { }; static DEFINE_PER_CPU(struct tsc_adjust, tsc_adjust); +static struct timer_list tsc_sync_check_timer; /* * TSC's on different sockets may be reset asynchronously. @@ -77,6 +78,46 @@ void tsc_verify_tsc_adjust(bool resume) } } +/* + * Normally the tsc_sync will be checked every time system enters idle + * state, but there is still caveat that a system won't enter idle, + * either because it's too busy or configured purposely to not enter + * idle. + * + * So setup a periodic timer (every 10 minutes) to make sure the check + * is always on. + */ + +#define SYNC_CHECK_INTERVAL (HZ * 600) + +static void tsc_sync_check_timer_fn(struct timer_list *unused) +{ + int next_cpu; + + tsc_verify_tsc_adjust(false); + + /* Run the check for all onlined CPUs in turn */ + next_cpu = cpumask_next(raw_smp_processor_id(), cpu_online_mask); + if (next_cpu >= nr_cpu_ids) + next_cpu = cpumask_first(cpu_online_mask); + + tsc_sync_check_timer.expires += SYNC_CHECK_INTERVAL; + add_timer_on(&tsc_sync_check_timer, next_cpu); +} + +static int __init start_sync_check_timer(void) +{ + if (!cpu_feature_enabled(X86_FEATURE_TSC_ADJUST) || tsc_clocksource_reliable) + return 0; + + timer_setup(&tsc_sync_check_timer, tsc_sync_check_timer_fn, 0); + tsc_sync_check_timer.expires = jiffies + SYNC_CHECK_INTERVAL; + add_timer(&tsc_sync_check_timer); + + return 0; +} +late_initcall(start_sync_check_timer); + static void tsc_sanitize_first_cpu(struct tsc_adjust *cur, s64 bootval, unsigned int cpu, bool bootcpu) { @@ -295,7 +336,7 @@ static cycles_t check_tsc_warp(unsigned int timeout) * But as the TSC is per-logical CPU and can potentially be modified wrongly * by the bios, TSC sync test for smaller duration should be able * to catch such errors. Also this will catch the condition where all the - * cores in the socket doesn't get reset at the same time. + * cores in the socket don't get reset at the same time. */ static inline unsigned int loop_timeout(int cpu) { @@ -472,7 +513,7 @@ retry: /* * Add the result to the previous adjustment value. * - * The adjustement value is slightly off by the overhead of the + * The adjustment value is slightly off by the overhead of the * sync mechanism (observed values are ~200 TSC cycles), but this * really depends on CPU, node distance and frequency. So * compensating for this is hard to get right. Experiments show |