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| author | Peter Zijlstra <peterz@infradead.org> | 2013-10-17 17:36:19 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-10-29 15:02:49 +0400 |
| commit | d9494cb4299da66541a3f3ab82c552889bee0606 (patch) | |
| tree | 5ffbb922c8eab879a582abd2b17335bde359634c /kernel/events/core.c | |
| parent | aac898548d04c7bff179b79f805874b0d6f87571 (diff) | |
| download | linux-d9494cb4299da66541a3f3ab82c552889bee0606.tar.xz | |
perf: Remove useless atomic_t
There's nothing atomic about atomic_set vs atomic_read; so remove the
atomic_t usage.
Also, make running_sample_length static as it really is (and should
be) local to this translation unit.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: eranian@google.com
Cc: Don Zickus <dzickus@redhat.com>
Cc: jmario@redhat.com
Cc: acme@infradead.org
Cc: dave.hansen@linux.intel.com
Link: http://lkml.kernel.org/n/tip-vw9lg588x1ic248whybjon0c@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events/core.c')
| -rw-r--r-- | kernel/events/core.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 5bd7fe43a7a2..028dad97760d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -175,8 +175,8 @@ int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; -static atomic_t perf_sample_allowed_ns __read_mostly = - ATOMIC_INIT( DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100); +static int perf_sample_allowed_ns __read_mostly = + DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; void update_perf_cpu_limits(void) { @@ -184,7 +184,7 @@ void update_perf_cpu_limits(void) tmp *= sysctl_perf_cpu_time_max_percent; do_div(tmp, 100); - atomic_set(&perf_sample_allowed_ns, tmp); + ACCESS_ONCE(perf_sample_allowed_ns) = tmp; } static int perf_rotate_context(struct perf_cpu_context *cpuctx); @@ -228,14 +228,15 @@ int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, * we detect that events are taking too long. */ #define NR_ACCUMULATED_SAMPLES 128 -DEFINE_PER_CPU(u64, running_sample_length); +static DEFINE_PER_CPU(u64, running_sample_length); void perf_sample_event_took(u64 sample_len_ns) { u64 avg_local_sample_len; u64 local_samples_len; + u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns); - if (atomic_read(&perf_sample_allowed_ns) == 0) + if (allowed_ns == 0) return; /* decay the counter by 1 average sample */ @@ -251,7 +252,7 @@ void perf_sample_event_took(u64 sample_len_ns) */ avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES; - if (avg_local_sample_len <= atomic_read(&perf_sample_allowed_ns)) + if (avg_local_sample_len <= allowed_ns) return; if (max_samples_per_tick <= 1) @@ -262,10 +263,9 @@ void perf_sample_event_took(u64 sample_len_ns) perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; printk_ratelimited(KERN_WARNING - "perf samples too long (%lld > %d), lowering " + "perf samples too long (%lld > %lld), lowering " "kernel.perf_event_max_sample_rate to %d\n", - avg_local_sample_len, - atomic_read(&perf_sample_allowed_ns), + avg_local_sample_len, allowed_ns, sysctl_perf_event_sample_rate); update_perf_cpu_limits(); |