[PATCH v3 1/4] perf/core,x86: introduce sync_task_ctx() method at struct pmu

From: Alexey Budankov
Date: Wed Oct 16 2019 - 10:25:28 EST



Declare sync_task_ctx() methods at the generic and x86 specific
pmu types to bridge calls to platform specific pmu code on optimized
context switch path between equivalent task perf event contexts.

Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
---
arch/x86/events/perf_event.h | 8 ++++++++
include/linux/perf_event.h | 7 +++++++
2 files changed, 15 insertions(+)

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index ecacfbf4ebc1..a25e6d7eb87b 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -682,6 +682,14 @@ struct x86_pmu {
*/
atomic_t lbr_exclusive[x86_lbr_exclusive_max];

+ /*
+ * perf task context (i.e. struct perf_event_context::task_ctx_data) switch helper
+ * to bridge calls from perf/core to perf/x86. See struct pmu::sync_task_ctx() usage
+ * for examples;
+ */
+ void (*sync_task_ctx)(struct x86_perf_task_context *one,
+ struct x86_perf_task_context *another);
+
/*
* AMD bits
*/
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 61448c19a132..60bf17af69f0 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -409,6 +409,13 @@ struct pmu {
*/
size_t task_ctx_size;

+ /*
+ * PMU specific parts of task perf event context (i.e. ctx->task_ctx_data)
+ * can be synchronized using this function. See Intel LBR callstack support
+ * implementation and Perf core context switch handling callbacks for usage
+ * examples.
+ */
+ void (*sync_task_ctx) (void *one, void *another);

/*
* Set up pmu-private data structures for an AUX area
--
2.20.1