perf evsel: Record fd into perf_mmap

Add a fd field into struct perf_mmap so that perf can track the mmap fd.

This feature will be used for toggling overwrite ring buffers.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1463762315-155689-3-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 7 insertions, 0 deletions

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index c4bfe11479a0..1a370db02a8c 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -881,6 +881,7 @@ static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx)
         if (evlist->mmap[idx].base != NULL) {
                 munmap(evlist->mmap[idx].base, evlist->mmap_len);
                 evlist->mmap[idx].base = NULL;
+                evlist->mmap[idx].fd = -1;
                 atomic_set(&evlist->mmap[idx].refcnt, 0);
         }
         auxtrace_mmap__munmap(&evlist->mmap[idx].auxtrace_mmap);
@@ -901,10 +902,14 @@ void perf_evlist__munmap(struct perf_evlist *evlist)
 
 static int perf_evlist__alloc_mmap(struct perf_evlist *evlist)
 {
+        int i;
+
         evlist->nr_mmaps = cpu_map__nr(evlist->cpus);
         if (cpu_map__empty(evlist->cpus))
                 evlist->nr_mmaps = thread_map__nr(evlist->threads);
         evlist->mmap = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
+        for (i = 0; i < evlist->nr_mmaps; i++)
+                evlist->mmap[i].fd = -1;
         return evlist->mmap != NULL ? 0 : -ENOMEM;
 }
 
@@ -941,6 +946,7 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
                 evlist->mmap[idx].base = NULL;
                 return -1;
         }
+        evlist->mmap[idx].fd = fd;
 
         if (auxtrace_mmap__mmap(&evlist->mmap[idx].auxtrace_mmap,
                                 &mp->auxtrace_mp, evlist->mmap[idx].base, fd))
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 85d1b59802e8..0d165b1d8f77 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -28,6 +28,7 @@ struct record_opts;
 struct perf_mmap {
         void             *base;
         int              mask;
+        int              fd;
         atomic_t         refcnt;
         u64              prev;
         struct auxtrace_mmap auxtrace_mmap;