diff mbox series

[v5,03/12] perf/core: add PERF_PMU_CAP_NO_EXCLUDE for exclusion incapable PMUs

Message ID 1547128414-50693-4-git-send-email-andrew.murray@arm.com
State Not Applicable
Headers show
Series perf/core: Generalise event exclusion checking | expand


Context Check Description
snowpatch_ozlabs/checkpatch warning total: 0 errors, 0 warnings, 1 checks, 22 lines checked
snowpatch_ozlabs/apply_patch success next/apply_patch Successfully applied

Commit Message

Andrew Murray Jan. 10, 2019, 1:53 p.m. UTC
Many PMU drivers do not have the capability to exclude counting events
that occur in specific contexts such as idle, kernel, guest, etc. These
drivers indicate this by returning an error in their event_init upon
testing the events attribute flags. This approach is error prone and
often inconsistent.

Let's instead allow PMU drivers to advertise their inability to exclude
based on context via a new capability: PERF_PMU_CAP_NO_EXCLUDE. This
allows the perf core to reject requests for exclusion events where
there is no support in the PMU.

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
 include/linux/perf_event.h | 1 +
 kernel/events/core.c       | 9 +++++++++
 2 files changed, 10 insertions(+)
diff mbox series


diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 54a78d2..cec02dc 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -244,6 +244,7 @@  struct perf_event;
 #define PERF_PMU_CAP_EXCLUSIVE			0x10
 #define PERF_PMU_CAP_ITRACE			0x20
+#define PERF_PMU_CAP_NO_EXCLUDE			0x80
  * struct pmu - generic performance monitoring unit
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3cd13a3..fbe59b7 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9772,6 +9772,15 @@  static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
 	if (ctx)
 		perf_event_ctx_unlock(event->group_leader, ctx);
+	if (!ret) {
+		if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
+				event_has_any_exclude_flag(event)) {
+			if (event->destroy)
+				event->destroy(event);
+			ret = -EINVAL;
+		}
+	}
 	if (ret)