diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace_hwlat.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c index 2f7b94e98317..3fe274b84f1c 100644 --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -102,9 +102,9 @@ struct hwlat_sample { /* keep the global state somewhere. */ static struct hwlat_data { - struct mutex lock; /* protect changes */ + struct mutex lock; /* protect changes */ - u64 count; /* total since reset */ + atomic64_t count; /* total since reset */ u64 sample_window; /* total sampling window (on+off) */ u64 sample_width; /* active sampling portion of window */ @@ -193,8 +193,7 @@ void trace_hwlat_callback(bool enter) * get_sample - sample the CPU TSC and look for likely hardware latencies * * Used to repeatedly capture the CPU TSC (or similar), looking for potential - * hardware-induced latency. Called with interrupts disabled and with - * hwlat_data.lock held. + * hardware-induced latency. Called with interrupts disabled. */ static int get_sample(void) { @@ -204,6 +203,7 @@ static int get_sample(void) time_type start, t1, t2, last_t2; s64 diff, outer_diff, total, last_total = 0; u64 sample = 0; + u64 sample_width = READ_ONCE(hwlat_data.sample_width); u64 thresh = tracing_thresh; u64 outer_sample = 0; int ret = -1; @@ -267,7 +267,7 @@ static int get_sample(void) if (diff > sample) sample = diff; /* only want highest value */ - } while (total <= hwlat_data.sample_width); + } while (total <= sample_width); barrier(); /* finish the above in the view for NMIs */ trace_hwlat_callback_enabled = false; @@ -285,8 +285,7 @@ static int get_sample(void) if (kdata->nmi_total_ts) do_div(kdata->nmi_total_ts, NSEC_PER_USEC); - hwlat_data.count++; - s.seqnum = hwlat_data.count; + s.seqnum = atomic64_inc_return(&hwlat_data.count); s.duration = sample; s.outer_duration = outer_sample; s.nmi_total_ts = kdata->nmi_total_ts; @@ -832,7 +831,7 @@ static int hwlat_tracer_init(struct trace_array *tr) hwlat_trace = tr; - hwlat_data.count = 0; + atomic64_set(&hwlat_data.count, 0); tr->max_latency = 0; save_tracing_thresh = tracing_thresh; |