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| author | Ingo Molnar <mingo@kernel.org> | 2015-02-04 07:53:17 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-02-04 07:53:17 +0100 |
| commit | 2622e849a1d3d3ef531d1cc33308bb7fd00eee40 (patch) | |
| tree | f2be9d9f08444cb93b3a8f87099fe4ff8ac3cd57 /arch/arm/kernel/perf_event.c | |
| parent | 996636ddae5cab8883bd76b996cd4f2ea9a152be (diff) | |
| parent | e36f014edff70fc02b3d3d79cead1d58f289332e (diff) | |
| download | kernel_replicant_linux-2622e849a1d3d3ef531d1cc33308bb7fd00eee40.tar.gz kernel_replicant_linux-2622e849a1d3d3ef531d1cc33308bb7fd00eee40.tar.bz2 kernel_replicant_linux-2622e849a1d3d3ef531d1cc33308bb7fd00eee40.zip | |
Merge tag 'v3.19-rc7' into locking/core, to refresh the branch before applying new changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/arm/kernel/perf_event.c')
| -rw-r--r-- | arch/arm/kernel/perf_event.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index f7c65adaa428..557e128e4df0 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -116,8 +116,14 @@ int armpmu_event_set_period(struct perf_event *event) ret = 1; } - if (left > (s64)armpmu->max_period) - left = armpmu->max_period; + /* + * Limit the maximum period to prevent the counter value + * from overtaking the one we are about to program. In + * effect we are reducing max_period to account for + * interrupt latency (and we are being very conservative). + */ + if (left > (armpmu->max_period >> 1)) + left = armpmu->max_period >> 1; local64_set(&hwc->prev_count, (u64)-left); |