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authorLike Xu2019-10-27 18:52:38 +0800
committerPaolo Bonzini2019-11-15 11:44:06 +0100
commit3ca270fc9edb258d5bfa271bcf851614e9e6e7d4 (patch)
tree4605da2cdbf886dac007befe055832134cf985e4 /include/linux/perf_event.h
parent02d496cfb88a4856b9d67ade32317077c510aebc (diff)
perf/core: Provide a kernel-internal interface to recalibrate event period
Currently, perf_event_period() is used by user tools via ioctl. Based on naming convention, exporting perf_event_period() for kernel users (such as KVM) who may recalibrate the event period for their assigned counter according to their requirements. The perf_event_period() is an external accessor, just like the perf_event_{en,dis}able() and should thus use perf_event_ctx_lock(). Suggested-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Like Xu <like.xu@linux.intel.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include/linux/perf_event.h')
-rw-r--r--include/linux/perf_event.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 61448c19a132..d601df36e671 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1336,6 +1336,7 @@ extern void perf_event_disable_local(struct perf_event *event);
extern void perf_event_disable_inatomic(struct perf_event *event);
extern void perf_event_task_tick(void);
extern int perf_event_account_interrupt(struct perf_event *event);
+extern int perf_event_period(struct perf_event *event, u64 value);
#else /* !CONFIG_PERF_EVENTS: */
static inline void *
perf_aux_output_begin(struct perf_output_handle *handle,
@@ -1415,6 +1416,10 @@ static inline void perf_event_disable(struct perf_event *event) { }
static inline int __perf_event_disable(void *info) { return -1; }
static inline void perf_event_task_tick(void) { }
static inline int perf_event_release_kernel(struct perf_event *event) { return 0; }
+static inline int perf_event_period(struct perf_event *event, u64 value)
+{
+ return -EINVAL;
+}
#endif
#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL)