perf/core, perf/x86: Introduce swap_task_ctx() method at 'struct pmu'

Declare swap_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@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/9a0aa84a-f062-9b64-3133-373658550c4b@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index ecacfbf..5384317 100644 (file)
--- 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::swap_task_ctx() usage for examples;
+        */
+       void            (*swap_task_ctx)(struct perf_event_context *prev,
+                                        struct perf_event_context *next);
+
        /*
         * AMD bits
         */

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 4f77b22..011dcbd 100644 (file)
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -410,6 +410,15 @@ 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 (*swap_task_ctx)           (struct perf_event_context *prev,
+                                        struct perf_event_context *next);
+                                       /* optional */
 
        /*
         * Set up pmu-private data structures for an AUX area