libperf: Introduce perf_evlist__for_each_mmap()

Add the perf_evlist__for_each_mmap() function and export it in the
perf/evlist.h header, so that the user can iterate through 'struct
perf_mmap' objects.

Add a internal perf_mmap__link() function to do the actual linking.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20191017105918.20873-2-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 25 insertions, 1 deletions

diff --git a/tools/perf/lib/evlist.c b/tools/perf/lib/evlist.c
index 65045614c938..854efff1519d 100644
--- a/tools/perf/lib/evlist.c
+++ b/tools/perf/lib/evlist.c
@@ -347,6 +347,8 @@ static struct perf_mmap* perf_evlist__alloc_mmap(struct perf_evlist *evlist, boo
 		return NULL;
 
 	for (i = 0; i < evlist->nr_mmaps; i++) {
+		struct perf_mmap *prev = i ? &map[i - 1] : NULL;
+
 		/*
 		 * When the perf_mmap() call is made we grab one refcount, plus
 		 * one extra to let perf_mmap__consume() get the last
@@ -356,7 +358,7 @@ static struct perf_mmap* perf_evlist__alloc_mmap(struct perf_evlist *evlist, boo
 		 * Each PERF_EVENT_IOC_SET_OUTPUT points to this mmap and
 		 * thus does perf_mmap__get() on it.
 		 */
-		perf_mmap__init(&map[i], overwrite, NULL);
+		perf_mmap__init(&map[i], prev, overwrite, NULL);
 	}
 
 	return map;
@@ -405,6 +407,15 @@ perf_evlist__mmap_cb_mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
 	return perf_mmap__mmap(map, mp, output, cpu);
 }
 
+static void perf_evlist__set_mmap_first(struct perf_evlist *evlist, struct perf_mmap *map,
+					bool overwrite)
+{
+	if (overwrite)
+		evlist->mmap_ovw_first = map;
+	else
+		evlist->mmap_first = map;
+}
+
 static int
 mmap_per_evsel(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
 	       int idx, struct perf_mmap_param *mp, int cpu_idx,
@@ -460,6 +471,9 @@ mmap_per_evsel(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
 
 			if (ops->mmap(map, mp, *output, evlist_cpu) < 0)
 				return -1;
+
+			if (!idx)
+				perf_evlist__set_mmap_first(evlist, map, overwrite);
 		} else {
 			if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0)
 				return -1;
@@ -605,3 +619,13 @@ void perf_evlist__munmap(struct perf_evlist *evlist)
 	zfree(&evlist->mmap);
 	zfree(&evlist->mmap_ovw);
 }
+
+struct perf_mmap*
+perf_evlist__next_mmap(struct perf_evlist *evlist, struct perf_mmap *map,
+		       bool overwrite)
+{
+	if (map)
+		return map->next;
+
+	return overwrite ? evlist->mmap_ovw_first : evlist->mmap_first;
+}