linux-kernel - [PATCH v2 6/7] perf: avoid double checking CPU and cgroup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 24 Jul 2019 15:37:45 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        linux-kernel@...r.kernel.org
Cc:     Kan Liang <kan.liang@...ux.intel.com>,
        Stephane Eranian <eranian@...gle.com>,
        Ian Rogers <irogers@...gle.com>
Subject: [PATCH v2 6/7] perf: avoid double checking CPU and cgroup

When ctx_groups_sched_in iterates the CPU and cgroup of events is known
to match the current task. Avoid double checking this with
event_filter_match by passing in an additional argument.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 kernel/events/core.c | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index c8b9c8611533..fb1027387e8e 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2077,10 +2077,12 @@ static inline int pmu_filter_match(struct perf_event *event)
 }
 
 static inline int
-event_filter_match(struct perf_event *event)
+event_filter_match(struct perf_event *event, bool check_cgroup_and_cpu)
 {
-	return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
-	       perf_cgroup_match(event) && pmu_filter_match(event);
+	return (!check_cgroup_and_cpu ||
+		((event->cpu == -1 || event->cpu == smp_processor_id()) &&
+		 perf_cgroup_match(event))) &&
+			pmu_filter_match(event);
 }
 
 static void
@@ -2801,7 +2803,7 @@ static void __perf_event_enable(struct perf_event *event,
 	if (!ctx->is_active)
 		return;
 
-	if (!event_filter_match(event)) {
+	if (!event_filter_match(event, /*check_cpu_and_cgroup=*/true)) {
 		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
 		return;
 	}
@@ -3578,7 +3580,10 @@ static int pinned_sched_in(struct perf_event_context *ctx,
 	if (event->state <= PERF_EVENT_STATE_OFF)
 		return 0;
 
-	if (!event_filter_match(event))
+	/* The caller already checked the CPU and cgroup before calling
+	 * pinned_sched_in.
+	 */
+	if (!event_filter_match(event, /*check_cpu_and_cgroup=*/false))
 		return 0;
 
 	if (group_can_go_on(event, cpuctx, 1)) {
@@ -3604,7 +3609,10 @@ static int flexible_sched_in(struct perf_event_context *ctx,
 	if (event->state <= PERF_EVENT_STATE_OFF)
 		return 0;
 
-	if (!event_filter_match(event))
+	/* The caller already checked the CPU and cgroup before calling
+	 * felxible_sched_in.
+	 */
+	if (!event_filter_match(event, /*check_cpu_and_cgroup=*/false))
 		return 0;
 
 	if (group_can_go_on(event, cpuctx, *can_add_hw)) {
@@ -3904,7 +3912,7 @@ static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
 		if (event->state != PERF_EVENT_STATE_ACTIVE)
 			continue;
 
-		if (!event_filter_match(event))
+		if (!event_filter_match(event, /*check_cpu_and_cgroup=*/true))
 			continue;
 
 		perf_pmu_disable(event->pmu);
@@ -6952,7 +6960,8 @@ perf_iterate_ctx(struct perf_event_context *ctx,
 		if (!all) {
 			if (event->state < PERF_EVENT_STATE_INACTIVE)
 				continue;
-			if (!event_filter_match(event))
+			if (!event_filter_match(event,
+						/*check_cpu_and_cgroup=*/true))
 				continue;
 		}
 
@@ -6976,7 +6985,7 @@ static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
 
 		if (event->state < PERF_EVENT_STATE_INACTIVE)
 			continue;
-		if (!event_filter_match(event))
+		if (!event_filter_match(event, /*check_cpu_and_cgroup=*/true))
 			continue;
 		output(event, data);
 	}
-- 
2.22.0.709.g102302147b-goog