[PATCH 13/36] libperf: Add perf_evlist__mmap()/munmap() functions

Jiri Olsa
2019-10-07T12:54:20Z

Add libperf's version of perf_evlist__mmap()/munmap() functions and
exporting them in the perf/evlist.h header.

It's the backbone of what we have in perf code. The following changes
will add needed callbacks and then we'll finally switch the perf code to
use libperf's version.

Add mmap/mmap_ovw 'struct perf_mmap' object arrays to hold maps for
libperf's evlist.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lore.kernel.org/lkml/20190913132355.21634-53-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/lib/evlist.c | 236 +++++++++++++++++++++++
tools/perf/lib/include/internal/evlist.h | 2 +
tools/perf/lib/include/perf/evlist.h | 3 +
tools/perf/lib/libperf.map | 2 +
4 files changed, 243 insertions(+)

diff --git a/tools/perf/lib/evlist.c b/tools/perf/lib/evlist.c
index d1496fee810c..250ad5752589 100644
--- a/tools/perf/lib/evlist.c
+++ b/tools/perf/lib/evlist.c
@@ -8,13 +8,20 @@
#include <internal/evlist.h>
#include <internal/evsel.h>
#include <internal/xyarray.h>
+#include <internal/mmap.h>
+#include <internal/cpumap.h>
+#include <internal/threadmap.h>
+#include <internal/xyarray.h>
+#include <internal/lib.h>
#include <linux/zalloc.h>
+#include <sys/ioctl.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <poll.h>
+#include <sys/mman.h>
#include <perf/cpumap.h>
#include <perf/threadmap.h>
#include <api/fd/array.h>
@@ -103,6 +110,10 @@ perf_evlist__next(struct perf_evlist *evlist, struct perf_evsel *prev)

void perf_evlist__delete(struct perf_evlist *evlist)
{
+ if (evlist == NULL)
+ return;
+
+ perf_evlist__munmap(evlist);
free(evlist);
}

@@ -281,3 +292,228 @@ int perf_evlist__poll(struct perf_evlist *evlist, int timeout)
{
return fdarray__poll(&evlist->pollfd, timeout);
}
+
+static struct perf_mmap* perf_evlist__alloc_mmap(struct perf_evlist *evlist, bool overwrite)
+{
+ int i;
+ struct perf_mmap *map;
+
+ evlist->nr_mmaps = perf_cpu_map__nr(evlist->cpus);
+ if (perf_cpu_map__empty(evlist->cpus))
+ evlist->nr_mmaps = perf_thread_map__nr(evlist->threads);
+
+ map = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
+ if (!map)
+ return NULL;
+
+ for (i = 0; i < evlist->nr_mmaps; i++) {
+ /*
+ * When the perf_mmap() call is made we grab one refcount, plus
+ * one extra to let perf_mmap__consume() get the last
+ * events after all real references (perf_mmap__get()) are
+ * dropped.
+ *
+ * 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);
+ }
+
+ return map;
+}
+
+static void perf_evlist__set_sid_idx(struct perf_evlist *evlist,
+ struct perf_evsel *evsel, int idx, int cpu,
+ int thread)
+{
+ struct perf_sample_id *sid = SID(evsel, cpu, thread);
+
+ sid->idx = idx;
+ if (evlist->cpus && cpu >= 0)
+ sid->cpu = evlist->cpus->map[cpu];
+ else
+ sid->cpu = -1;
+ if (!evsel->system_wide && evlist->threads && thread >= 0)
+ sid->tid = perf_thread_map__pid(evlist->threads, thread);
+ else
+ sid->tid = -1;
+}
+
+static struct perf_mmap*
+perf_evlist__map_get(struct perf_evlist *evlist, bool overwrite, int idx)
+{
+ struct perf_mmap *map = &evlist->mmap[idx];
+
+ if (overwrite) {
+ if (!evlist->mmap_ovw) {
+ evlist->mmap_ovw = perf_evlist__alloc_mmap(evlist, true);
+ if (!evlist->mmap_ovw)
+ return NULL;
+ }
+ map = &evlist->mmap_ovw[idx];
+ }
+
+ return map;
+}
+
+#define FD(e, x, y) (*(int *) xyarray__entry(e->fd, x, y))
+
+static int
+mmap_per_evsel(struct perf_evlist *evlist, int idx,
+ struct perf_mmap_param *mp, int cpu_idx,
+ int thread, int *_output, int *_output_overwrite)
+{
+ int evlist_cpu = perf_cpu_map__cpu(evlist->cpus, cpu_idx);
+ struct perf_evsel *evsel;
+ int revent;
+
+ perf_evlist__for_each_entry(evlist, evsel) {
+ bool overwrite = evsel->attr.write_backward;
+ struct perf_mmap *map;
+ int *output, fd, cpu;
+
+ if (evsel->system_wide && thread)
+ continue;
+
+ cpu = perf_cpu_map__idx(evsel->cpus, evlist_cpu);
+ if (cpu == -1)
+ continue;
+
+ map = perf_evlist__map_get(evlist, overwrite, idx);
+ if (map == NULL)
+ return -ENOMEM;
+
+ if (overwrite) {
+ mp->prot = PROT_READ;
+ output = _output_overwrite;
+ } else {
+ mp->prot = PROT_READ | PROT_WRITE;
+ output = _output;
+ }
+
+ fd = FD(evsel, cpu, thread);
+
+ if (*output == -1) {
+ *output = fd;
+
+ if (perf_mmap__mmap(map, mp, *output, evlist_cpu) < 0)
+ return -1;
+ } else {
+ if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0)
+ return -1;
+
+ perf_mmap__get(map);
+ }
+
+ revent = !overwrite ? POLLIN : 0;
+
+ if (!evsel->system_wide &&
+ perf_evlist__add_pollfd(evlist, fd, map, revent) < 0) {
+ perf_mmap__put(map);
+ return -1;
+ }
+
+ if (evsel->attr.read_format & PERF_FORMAT_ID) {
+ if (perf_evlist__id_add_fd(evlist, evsel, cpu, thread,
+ fd) < 0)
+ return -1;
+ perf_evlist__set_sid_idx(evlist, evsel, idx, cpu,
+ thread);
+ }
+ }
+
+ return 0;
+}
+
+static int
+mmap_per_thread(struct perf_evlist *evlist, struct perf_mmap_param *mp)
+{
+ int thread;
+ int nr_threads = perf_thread_map__nr(evlist->threads);
+
+ for (thread = 0; thread < nr_threads; thread++) {
+ int output = -1;
+ int output_overwrite = -1;
+
+ if (mmap_per_evsel(evlist, thread, mp, 0, thread,
+ &output, &output_overwrite))
+ goto out_unmap;
+ }
+
+ return 0;
+
+out_unmap:
+ perf_evlist__munmap(evlist);
+ return -1;
+}
+
+static int
+mmap_per_cpu(struct perf_evlist *evlist, struct perf_mmap_param *mp)
+{
+ int nr_threads = perf_thread_map__nr(evlist->threads);
+ int nr_cpus = perf_cpu_map__nr(evlist->cpus);
+ int cpu, thread;
+
+ for (cpu = 0; cpu < nr_cpus; cpu++) {
+ int output = -1;
+ int output_overwrite = -1;
+
+ for (thread = 0; thread < nr_threads; thread++) {
+ if (mmap_per_evsel(evlist, cpu, mp, cpu,
+ thread, &output, &output_overwrite))
+ goto out_unmap;
+ }
+ }
+
+ return 0;
+
+out_unmap:
+ perf_evlist__munmap(evlist);
+ return -1;
+}
+
+int perf_evlist__mmap(struct perf_evlist *evlist, int pages)
+{
+ struct perf_evsel *evsel;
+ const struct perf_cpu_map *cpus = evlist->cpus;
+ const struct perf_thread_map *threads = evlist->threads;
+ struct perf_mmap_param mp;
+
+ if (!evlist->mmap)
+ evlist->mmap = perf_evlist__alloc_mmap(evlist, false);
+ if (!evlist->mmap)
+ return -ENOMEM;
+
+ perf_evlist__for_each_entry(evlist, evsel) {
+ if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
+ evsel->sample_id == NULL &&
+ perf_evsel__alloc_id(evsel, perf_cpu_map__nr(cpus), threads->nr) < 0)
+ return -ENOMEM;
+ }
+
+ evlist->mmap_len = (pages + 1) * page_size;
+ mp.mask = evlist->mmap_len - page_size - 1;
+
+ if (perf_cpu_map__empty(cpus))
+ return mmap_per_thread(evlist, &mp);
+
+ return mmap_per_cpu(evlist, &mp);
+}
+
+void perf_evlist__munmap(struct perf_evlist *evlist)
+{
+ int i;
+
+ if (evlist->mmap) {
+ for (i = 0; i < evlist->nr_mmaps; i++)
+ perf_mmap__munmap(&evlist->mmap[i]);
+ }
+
+ if (evlist->mmap_ovw) {
+ for (i = 0; i < evlist->nr_mmaps; i++)
+ perf_mmap__munmap(&evlist->mmap_ovw[i]);
+ }
+
+ zfree(&evlist->mmap);
+ zfree(&evlist->mmap_ovw);
+}
diff --git a/tools/perf/lib/include/internal/evlist.h b/tools/perf/lib/include/internal/evlist.h
index 9f440ab12b76..4438a19ceba3 100644
--- a/tools/perf/lib/include/internal/evlist.h
+++ b/tools/perf/lib/include/internal/evlist.h
@@ -22,6 +22,8 @@ struct perf_evlist {
size_t mmap_len;
struct fdarray pollfd;
struct hlist_head heads[PERF_EVLIST__HLIST_SIZE];
+ struct perf_mmap *mmap;
+ struct perf_mmap *mmap_ovw;
};

int perf_evlist__alloc_pollfd(struct perf_evlist *evlist);
diff --git a/tools/perf/lib/include/perf/evlist.h b/tools/perf/lib/include/perf/evlist.h
index 8a2ce0757ab2..28b6a12a8a2b 100644
--- a/tools/perf/lib/include/perf/evlist.h
+++ b/tools/perf/lib/include/perf/evlist.h
@@ -33,4 +33,7 @@ LIBPERF_API void perf_evlist__set_maps(struct perf_evlist *evlist,
struct perf_thread_map *threads);
LIBPERF_API int perf_evlist__poll(struct perf_evlist *evlist, int timeout);

+LIBPERF_API int perf_evlist__mmap(struct perf_evlist *evlist, int pages);
+LIBPERF_API void perf_evlist__munmap(struct perf_evlist *evlist);
+
#endif /* __LIBPERF_EVLIST_H */
diff --git a/tools/perf/lib/libperf.map b/tools/perf/lib/libperf.map
index 8bb0d73e0c6c..5a18fd1aacf2 100644
--- a/tools/perf/lib/libperf.map
+++ b/tools/perf/lib/libperf.map
@@ -40,6 +40,8 @@ LIBPERF_0.0.1 {
perf_evlist__next;
perf_evlist__set_maps;
perf_evlist__poll;
+ perf_evlist__mmap;
+ perf_evlist__munmap;
perf_mmap__consume;
perf_mmap__read_init;
perf_mmap__read_done;
--
2.21.0