linux-kernel - [PATCH 1/2] perf evsel: add per{cpu,thread} close helpers

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Date:   Fri, 28 Apr 2017 12:47:09 +0100
From:   Mark Rutland <mark.rutland@....com>
To:     linux-kernel@...r.kernel.org
Cc:     acme@...nel.org, alexander.shishkin@...ux.intel.com,
        ganapatrao.kulkarni@...ium.com, mark.rutland@....com
Subject: [PATCH 1/2] perf evsel: add per{cpu,thread} close helpers

We have perf_evsel__open_per_{cpu,thread}() helpers for opening events,
but we have no corresponding helpers for closing events.

This results in callers having to duplicate logic to determine the
number of cpus and threads when closing an event, and makes it harder
than necessary to determine whether open/close are correctly balanced.

This patch adds new perf_evsel__close_per_{cpu,thread}() helpers, which
can be paired with their open counterpart. A subsequent patch will make
use of these.

For consistency, the functions are shuffled in evsel.c so that the
per-{cpu,thread} variants of open/close immediately follow their
respective common implementation.

Signed-off-by: Mark Rutland <mark.rutland@....com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: linux-kernel@...r.kernel.org
---
 tools/perf/util/evsel.c | 26 ++++++++++++++++++++------
 tools/perf/util/evsel.h |  4 ++++
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 0e87909..27abed8 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1682,6 +1682,18 @@ int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
 	return err;
 }
 
+int perf_evsel__open_per_cpu(struct perf_evsel *evsel,
+			     struct cpu_map *cpus)
+{
+	return perf_evsel__open(evsel, cpus, NULL);
+}
+
+int perf_evsel__open_per_thread(struct perf_evsel *evsel,
+				struct thread_map *threads)
+{
+	return perf_evsel__open(evsel, NULL, threads);
+}
+
 void perf_evsel__close(struct perf_evsel *evsel, int ncpus, int nthreads)
 {
 	if (evsel->fd == NULL)
@@ -1691,16 +1703,18 @@ void perf_evsel__close(struct perf_evsel *evsel, int ncpus, int nthreads)
 	perf_evsel__free_fd(evsel);
 }
 
-int perf_evsel__open_per_cpu(struct perf_evsel *evsel,
-			     struct cpu_map *cpus)
+void perf_evsel__close_per_cpu(struct perf_evsel *evsel,
+			       struct cpu_map *cpus)
 {
-	return perf_evsel__open(evsel, cpus, NULL);
+	int ncpus = cpus ? cpus->nr : 1;
+	perf_evsel__close(evsel, ncpus, 1);
 }
 
-int perf_evsel__open_per_thread(struct perf_evsel *evsel,
-				struct thread_map *threads)
+void perf_evsel__close_per_thread(struct perf_evsel *evsel,
+				  struct thread_map *threads)
 {
-	return perf_evsel__open(evsel, NULL, threads);
+	int nthreads = threads ? threads->nr : 1;
+	perf_evsel__close(evsel, 1, nthreads);
 }
 
 static int perf_evsel__parse_id_sample(const struct perf_evsel *evsel,
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index d101695..6f61a49 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -257,6 +257,10 @@ int perf_evsel__open_per_thread(struct perf_evsel *evsel,
 				struct thread_map *threads);
 int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
 		     struct thread_map *threads);
+void perf_evsel__close_per_cpu(struct perf_evsel *evsel,
+			       struct cpu_map *cpus);
+void perf_evsel__close_per_thread(struct perf_evsel *evsel,
+				  struct thread_map *threads);
 void perf_evsel__close(struct perf_evsel *evsel, int ncpus, int nthreads);
 
 struct perf_sample;
-- 
1.9.1