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>

diff --git a/tools/perf/lib/evlist.c b/tools/perf/lib/evlist.c
index 6504561..854efff 100644 (file)
--- 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;
+}

diff --git a/tools/perf/lib/include/internal/evlist.h b/tools/perf/lib/include/internal/evlist.h
index be0b25a..20d90e2 100644 (file)
--- a/tools/perf/lib/include/internal/evlist.h
+++ b/tools/perf/lib/include/internal/evlist.h
@@ -25,6 +25,8 @@ struct perf_evlist {
        struct hlist_head        heads[PERF_EVLIST__HLIST_SIZE];
        struct perf_mmap        *mmap;
        struct perf_mmap        *mmap_ovw;
+       struct perf_mmap        *mmap_first;
+       struct perf_mmap        *mmap_ovw_first;
 };
 
 typedef void

diff --git a/tools/perf/lib/include/internal/mmap.h b/tools/perf/lib/include/internal/mmap.h
index ee536c4..be7556e 100644 (file)
--- a/tools/perf/lib/include/internal/mmap.h
+++ b/tools/perf/lib/include/internal/mmap.h
@@ -32,6 +32,7 @@ struct perf_mmap {
        u64                      flush;
        libperf_unmap_cb_t       unmap_cb;
        char                     event_copy[PERF_SAMPLE_MAX_SIZE] __aligned(8);
+       struct perf_mmap        *next;
 };
 
 struct perf_mmap_param {
@@ -41,8 +42,8 @@ struct perf_mmap_param {
 
 size_t perf_mmap__mmap_len(struct perf_mmap *map);
 
-void perf_mmap__init(struct perf_mmap *map, bool overwrite,
-                    libperf_unmap_cb_t unmap_cb);
+void perf_mmap__init(struct perf_mmap *map, struct perf_mmap *prev,
+                    bool overwrite, libperf_unmap_cb_t unmap_cb);
 int perf_mmap__mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
                    int fd, int cpu);
 void perf_mmap__munmap(struct perf_mmap *map);

diff --git a/tools/perf/lib/include/perf/evlist.h b/tools/perf/lib/include/perf/evlist.h
index 16f526e..8c4b3c2 100644 (file)
--- a/tools/perf/lib/include/perf/evlist.h
+++ b/tools/perf/lib/include/perf/evlist.h
@@ -3,6 +3,7 @@
 #define __LIBPERF_EVLIST_H
 
 #include <perf/core.h>
+#include <stdbool.h>
 
 struct perf_evlist;
 struct perf_evsel;
@@ -38,4 +39,12 @@ LIBPERF_API int perf_evlist__filter_pollfd(struct perf_evlist *evlist,
 LIBPERF_API int perf_evlist__mmap(struct perf_evlist *evlist, int pages);
 LIBPERF_API void perf_evlist__munmap(struct perf_evlist *evlist);
 
+LIBPERF_API struct perf_mmap *perf_evlist__next_mmap(struct perf_evlist *evlist,
+                                                    struct perf_mmap *map,
+                                                    bool overwrite);
+#define perf_evlist__for_each_mmap(evlist, pos, overwrite)             \
+       for ((pos) = perf_evlist__next_mmap((evlist), NULL, overwrite); \
+            (pos) != NULL;                                             \
+            (pos) = perf_evlist__next_mmap((evlist), (pos), overwrite))
+
 #endif /* __LIBPERF_EVLIST_H */

diff --git a/tools/perf/lib/libperf.map b/tools/perf/lib/libperf.map
index 2184aba..8be02af 100644 (file)
--- a/tools/perf/lib/libperf.map
+++ b/tools/perf/lib/libperf.map
@@ -43,6 +43,7 @@ LIBPERF_0.0.1 {
                perf_evlist__mmap;
                perf_evlist__munmap;
                perf_evlist__filter_pollfd;
+               perf_evlist__next_mmap;
                perf_mmap__consume;
                perf_mmap__read_init;
                perf_mmap__read_done;

diff --git a/tools/perf/lib/mmap.c b/tools/perf/lib/mmap.c
index 0752c19..79d5ed6 100644 (file)
--- a/tools/perf/lib/mmap.c
+++ b/tools/perf/lib/mmap.c
@@ -13,13 +13,15 @@
 #include <linux/kernel.h>
 #include "internal.h"
 
-void perf_mmap__init(struct perf_mmap *map, bool overwrite,
-                    libperf_unmap_cb_t unmap_cb)
+void perf_mmap__init(struct perf_mmap *map, struct perf_mmap *prev,
+                    bool overwrite, libperf_unmap_cb_t unmap_cb)
 {
        map->fd = -1;
        map->overwrite = overwrite;
        map->unmap_cb  = unmap_cb;
        refcount_set(&map->refcnt, 0);
+       if (prev)
+               prev->next = map;
 }
 
 size_t perf_mmap__mmap_len(struct perf_mmap *map)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 0f9cd70..6cda5a3 100644 (file)
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -607,6 +607,8 @@ static struct mmap *evlist__alloc_mmap(struct evlist *evlist,
                return NULL;
 
        for (i = 0; i < evlist->core.nr_mmaps; i++) {
+               struct perf_mmap *prev = i ? &map[i - 1].core : NULL;
+
                /*
                 * When the perf_mmap() call is made we grab one refcount, plus
                 * one extra to let perf_mmap__consume() get the last
@@ -616,7 +618,7 @@ static struct mmap *evlist__alloc_mmap(struct evlist *evlist,
                 * Each PERF_EVENT_IOC_SET_OUTPUT points to this mmap and
                 * thus does perf_mmap__get() on it.
                 */
-               perf_mmap__init(&map[i].core, overwrite, perf_mmap__unmap_cb);
+               perf_mmap__init(&map[i].core, prev, overwrite, perf_mmap__unmap_cb);
        }
 
        return map;