The event copy in the mmap is used to have storage to a read
event. Not all users of mmaps read the events, such as perf record, so
switch the allocation to being on first read rather than being
embedded within the perf_mmap.
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
tools/lib/perf/include/internal/mmap.h | 2 +-
tools/lib/perf/mmap.c | 9 +++++++++
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/tools/lib/perf/include/internal/mmap.h b/tools/lib/perf/include/internal/mmap.h
index 5a062af8e9d8..b11aaf5ed645 100644
--- a/tools/lib/perf/include/internal/mmap.h
+++ b/tools/lib/perf/include/internal/mmap.h
@@ -33,7 +33,7 @@ struct perf_mmap {
bool overwrite;
u64 flush;
libperf_unmap_cb_t unmap_cb;
- char event_copy[PERF_SAMPLE_MAX_SIZE] __aligned(8);
+ void *event_copy;
struct perf_mmap *next;
};
diff --git a/tools/lib/perf/mmap.c b/tools/lib/perf/mmap.c
index 2184814b37dd..91ae46aac378 100644
--- a/tools/lib/perf/mmap.c
+++ b/tools/lib/perf/mmap.c
@@ -51,6 +51,8 @@ int perf_mmap__mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
void perf_mmap__munmap(struct perf_mmap *map)
{
+ free(map->event_copy);
+ map->event_copy = NULL;
if (map && map->base != NULL) {
munmap(map->base, perf_mmap__mmap_len(map));
map->base = NULL;
@@ -226,6 +228,13 @@ static union perf_event *perf_mmap__read(struct perf_mmap *map,
unsigned int len = min(sizeof(*event), size), cpy;
void *dst = map->event_copy;
+ if (!dst) {
+ dst = malloc(PERF_SAMPLE_MAX_SIZE);
+ if (!dst)
+ return NULL;
+ map->event_copy = dst;
+ }
+
do {
cpy = min(map->mask + 1 - (offset & map->mask), len);
memcpy(dst, &data[offset & map->mask], cpy);
--
2.42.0.609.gbb76f46606-goog
