perf mmap: Map data buffer for preserving collected data

The map->data buffer is used to preserve map->base profiling data for
writing to disk. AIO map->cblock is used to queue corresponding
map->data buffer for asynchronous writing.

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5fcda10c-6c63-68df-383a-c6d9e5d1f918@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 48 insertions, 1 deletions

diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index cdb95b3a1213..47cdc3ad6546 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -153,8 +153,55 @@ void __weak auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp __mayb
 {
 }
 
+#ifdef HAVE_AIO_SUPPORT
+static int perf_mmap__aio_mmap(struct perf_mmap *map, struct mmap_params *mp)
+{
+	int delta_max;
+
+	if (mp->nr_cblocks) {
+		map->aio.data = malloc(perf_mmap__mmap_len(map));
+		if (!map->aio.data) {
+			pr_debug2("failed to allocate data buffer, error %m\n");
+			return -1;
+		}
+		/*
+		 * Use cblock.aio_fildes value different from -1
+		 * to denote started aio write operation on the
+		 * cblock so it requires explicit record__aio_sync()
+		 * call prior the cblock may be reused again.
+		 */
+		map->aio.cblock.aio_fildes = -1;
+		/*
+		 * Allocate cblock with max priority delta to
+		 * have faster aio write system calls.
+		 */
+		delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX);
+		map->aio.cblock.aio_reqprio = delta_max;
+	}
+
+	return 0;
+}
+
+static void perf_mmap__aio_munmap(struct perf_mmap *map)
+{
+	if (map->aio.data)
+		zfree(&map->aio.data);
+}
+#else
+static int perf_mmap__aio_mmap(struct perf_mmap *map __maybe_unused,
+			       struct mmap_params *mp __maybe_unused)
+{
+	return 0;
+}
+
+static void perf_mmap__aio_munmap(struct perf_mmap *map __maybe_unused)
+{
+}
+#endif
+
 void perf_mmap__munmap(struct perf_mmap *map)
 {
+	perf_mmap__aio_munmap(map);
 	if (map->base != NULL) {
 		munmap(map->base, perf_mmap__mmap_len(map));
 		map->base = NULL;
@@ -197,7 +244,7 @@ int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int c
 				&mp->auxtrace_mp, map->base, fd))
 		return -1;
 
-	return 0;
+	return perf_mmap__aio_mmap(map, mp);
 }
 
 static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end)