perf bpf: Clone bpf stdout events in multiple bpf scripts

This patch allows cloning bpf-output event configuration among multiple
bpf scripts. If there exist a map named '__bpf_output__' and not
configured using 'map:__bpf_output__.event=', this patch clones the
configuration of another '__bpf_stdout__' map. For example, following
command:

  # perf trace --ev bpf-output/no-inherit,name=evt/ \
               --ev ./test_bpf_trace.c/map:__bpf_stdout__.event=evt/ \
               --ev ./test_bpf_trace2.c usleep 100000

equals to:

  # perf trace --ev bpf-output/no-inherit,name=evt/ \
               --ev ./test_bpf_trace.c/map:__bpf_stdout__.event=evt/  \
               --ev ./test_bpf_trace2.c/map:__bpf_stdout__.event=evt/ \
               usleep 100000

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1460128045-97310-4-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 410035c..e64bd1e 100644 (file)
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1276,6 +1276,14 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
        if (err)
                return err;
 
+       err = bpf__setup_stdout(rec->evlist);
+       if (err) {
+               bpf__strerror_setup_stdout(rec->evlist, err, errbuf, sizeof(errbuf));
+               pr_err("ERROR: Setup BPF stdout failed: %s\n",
+                        errbuf);
+               return err;
+       }
+
        err = -ENOMEM;
 
        symbol__init(NULL);

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 11290b5..27d9870 100644 (file)
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -3273,6 +3273,13 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
        argc = parse_options_subcommand(argc, argv, trace_options, trace_subcommands,
                                 trace_usage, PARSE_OPT_STOP_AT_NON_OPTION);
 
+       err = bpf__setup_stdout(trace.evlist);
+       if (err) {
+               bpf__strerror_setup_stdout(trace.evlist, err, bf, sizeof(bf));
+               pr_err("ERROR: Setup BPF stdout failed: %s\n", bf);
+               goto out;
+       }
+
        if (trace.trace_pgfaults) {
                trace.opts.sample_address = true;
                trace.opts.sample_time = true;

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 0967ce6..67f61a9 100644 (file)
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -842,6 +842,58 @@ bpf_map_op__new(struct parse_events_term *term)
        return op;
 }
 
+static struct bpf_map_op *
+bpf_map_op__clone(struct bpf_map_op *op)
+{
+       struct bpf_map_op *newop;
+
+       newop = memdup(op, sizeof(*op));
+       if (!newop) {
+               pr_debug("Failed to alloc bpf_map_op\n");
+               return NULL;
+       }
+
+       INIT_LIST_HEAD(&newop->list);
+       if (op->key_type == BPF_MAP_KEY_RANGES) {
+               size_t memsz = op->k.array.nr_ranges *
+                              sizeof(op->k.array.ranges[0]);
+
+               newop->k.array.ranges = memdup(op->k.array.ranges, memsz);
+               if (!newop->k.array.ranges) {
+                       pr_debug("Failed to alloc indices for map\n");
+                       free(newop);
+                       return NULL;
+               }
+       }
+
+       return newop;
+}
+
+static struct bpf_map_priv *
+bpf_map_priv__clone(struct bpf_map_priv *priv)
+{
+       struct bpf_map_priv *newpriv;
+       struct bpf_map_op *pos, *newop;
+
+       newpriv = zalloc(sizeof(*newpriv));
+       if (!newpriv) {
+               pr_debug("No enough memory to alloc map private\n");
+               return NULL;
+       }
+       INIT_LIST_HEAD(&newpriv->ops_list);
+
+       list_for_each_entry(pos, &priv->ops_list, list) {
+               newop = bpf_map_op__clone(pos);
+               if (!newop) {
+                       bpf_map_priv__purge(newpriv);
+                       return NULL;
+               }
+               list_add_tail(&newop->list, &newpriv->ops_list);
+       }
+
+       return newpriv;
+}
+
 static int
 bpf_map__add_op(struct bpf_map *map, struct bpf_map_op *op)
 {
@@ -1417,6 +1469,70 @@ int bpf__apply_obj_config(void)
        return 0;
 }
 
+#define bpf__for_each_map(pos, obj, objtmp)    \
+       bpf_object__for_each_safe(obj, objtmp)  \
+               bpf_map__for_each(pos, obj)
+
+#define bpf__for_each_stdout_map(pos, obj, objtmp)     \
+       bpf__for_each_map(pos, obj, objtmp)             \
+               if (bpf_map__get_name(pos) &&           \
+                       (strcmp("__bpf_stdout__",       \
+                               bpf_map__get_name(pos)) == 0))
+
+int bpf__setup_stdout(struct perf_evlist *evlist __maybe_unused)
+{
+       struct bpf_map_priv *tmpl_priv = NULL;
+       struct bpf_object *obj, *tmp;
+       struct bpf_map *map;
+       int err;
+       bool need_init = false;
+
+       bpf__for_each_stdout_map(map, obj, tmp) {
+               struct bpf_map_priv *priv;
+
+               err = bpf_map__get_private(map, (void **)&priv);
+               if (err)
+                       return -BPF_LOADER_ERRNO__INTERNAL;
+
+               /*
+                * No need to check map type: type should have been
+                * verified by kernel.
+                */
+               if (!need_init && !priv)
+                       need_init = !priv;
+               if (!tmpl_priv && priv)
+                       tmpl_priv = priv;
+       }
+
+       if (!need_init)
+               return 0;
+
+       if (!tmpl_priv)
+               return 0;
+
+       bpf__for_each_stdout_map(map, obj, tmp) {
+               struct bpf_map_priv *priv;
+
+               err = bpf_map__get_private(map, (void **)&priv);
+               if (err)
+                       return -BPF_LOADER_ERRNO__INTERNAL;
+               if (priv)
+                       continue;
+
+               priv = bpf_map_priv__clone(tmpl_priv);
+               if (!priv)
+                       return -ENOMEM;
+
+               err = bpf_map__set_private(map, priv, bpf_map_priv__clear);
+               if (err) {
+                       bpf_map_priv__clear(map, priv);
+                       return err;
+               }
+       }
+
+       return 0;
+}
+
 #define ERRNO_OFFSET(e)                ((e) - __BPF_LOADER_ERRNO__START)
 #define ERRCODE_OFFSET(c)      ERRNO_OFFSET(BPF_LOADER_ERRNO__##c)
 #define NR_ERRNO       (__BPF_LOADER_ERRNO__END - __BPF_LOADER_ERRNO__START)
@@ -1590,3 +1706,11 @@ int bpf__strerror_apply_obj_config(int err, char *buf, size_t size)
        bpf__strerror_end(buf, size);
        return 0;
 }
+
+int bpf__strerror_setup_stdout(struct perf_evlist *evlist __maybe_unused,
+                              int err, char *buf, size_t size)
+{
+       bpf__strerror_head(err, buf, size);
+       bpf__strerror_end(buf, size);
+       return 0;
+}

diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index be43119..941e172 100644 (file)
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -79,6 +79,11 @@ int bpf__strerror_config_obj(struct bpf_object *obj,
                             size_t size);
 int bpf__apply_obj_config(void);
 int bpf__strerror_apply_obj_config(int err, char *buf, size_t size);
+
+int bpf__setup_stdout(struct perf_evlist *evlist);
+int bpf__strerror_setup_stdout(struct perf_evlist *evlist, int err,
+                              char *buf, size_t size);
+
 #else
 static inline struct bpf_object *
 bpf__prepare_load(const char *filename __maybe_unused,
@@ -125,6 +130,12 @@ bpf__apply_obj_config(void)
 }
 
 static inline int
+bpf__setup_stdout(struct perf_evlist *evlist __maybe_unused)
+{
+       return 0;
+}
+
+static inline int
 __bpf_strerror(char *buf, size_t size)
 {
        if (!size)
@@ -177,5 +188,13 @@ bpf__strerror_apply_obj_config(int err __maybe_unused,
 {
        return __bpf_strerror(buf, size);
 }
+
+static inline int
+bpf__strerror_setup_stdout(struct perf_evlist *evlist __maybe_unused,
+                          int err __maybe_unused, char *buf,
+                          size_t size)
+{
+       return __bpf_strerror(buf, size);
+}
 #endif
 #endif