[RFC PATCH 5/7] perf tools: Support setting different slots in a BPF map separately

[Wang Nan]

This patch introduces basic facilities to support config different
slots in a BPF map one by one.

nr_indics and indics are introduced into 'struct parse_events_term',
where indics is an array of indics which will be configured by this
config term, nr_indics is the size of the array. The array is passed
to 'struct bpf_map_priv'. To indicate the new type of configuration,
BPF_MAP_PRIV_KEY_INDICS is added as a new key type.
bpf_map_config_foreach_key() is extended to iterate over those indics
instead of all possible keys.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Cc: Brendan Gregg <brendan.d.gregg@xxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kaixu Xia <xiakaixu@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
---
 tools/perf/util/bpf-loader.c   | 68 +++++++++++++++++++++++++++++++++++++++++-
 tools/perf/util/parse-events.c |  4 ++-
 tools/perf/util/parse-events.h |  2 ++
 3 files changed, 72 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 15cf27a..023fc12 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -638,6 +638,7 @@ int bpf__foreach_tev(struct bpf_object *obj,
 
 enum bpf_map_priv_key_type {
 	BPF_MAP_PRIV_KEY_ALL,
+	BPF_MAP_PRIV_KEY_INDICS,
 };
 
 enum bpf_map_priv_value_type {
@@ -647,6 +648,12 @@ enum bpf_map_priv_value_type {
 struct bpf_map_priv {
 	struct {
 		enum bpf_map_priv_key_type type;
+		union {
+			struct {
+				size_t nr_indics;
+				u64 *indics;
+			} indics;
+		};
 	} key;
 
 	struct {
@@ -663,6 +670,8 @@ bpf_map_priv__clear(struct bpf_map *map __maybe_unused,
 {
 	struct bpf_map_priv *priv = _priv;
 
+	if (priv->key.type == BPF_MAP_PRIV_KEY_INDICS)
+		zfree(&priv->key.indics.indics);
 	free(priv);
 }
 
@@ -718,6 +727,20 @@ bpf_map_config_foreach_key(struct bpf_map *map,
 				}
 			}
 			return 0;
+		case BPF_MAP_PRIV_KEY_INDICS:
+			for (i = 0; i < priv->key.indics.nr_indics; i++) {
+				u64 _idx = priv->key.indics.indics[i];
+				unsigned int idx = (unsigned int)(_idx);
+
+				err = (*func)(name, map_fd, &def,
+					      priv, &idx, arg);
+				if (err) {
+					pr_debug("ERROR: failed to insert value to %s[%u]\n",
+						 name, idx);
+					return err;
+				}
+			}
+			return 0;
 		default:
 			pr_debug("ERROR: keytype for map '%s' invalid\n", name);
 			return -EINVAL;
@@ -728,6 +751,28 @@ bpf_map_config_foreach_key(struct bpf_map *map,
 	}
 }
 
+static int
+bpf_map_priv_setkey(struct bpf_map_priv *priv,
+		    struct parse_events_term *term,
+		    const char *map_name)
+{
+	if (!term->nr_indics)
+		priv->key.type = BPF_MAP_PRIV_KEY_ALL;
+	else {
+		size_t memsz = term->nr_indics * sizeof(term->indics[0]);
+
+		priv->key.indics.indics = malloc(memsz);
+		if (!priv->key.indics.indics) {
+			pr_debug("No enough memory to alloc indics for %s\n",
+				 map_name);
+			return -ENOMEM;
+		}
+		memcpy(priv->key.indics.indics, term->indics, memsz);
+		priv->key.type = BPF_MAP_PRIV_KEY_INDICS;
+		priv->key.indics.nr_indics = term->nr_indics;
+	}
+	return 0;
+}
 
 static int
 bpf__config_obj_map_array_value(struct bpf_map *map,
@@ -773,7 +818,9 @@ bpf__config_obj_map_array_value(struct bpf_map *map,
 		return -ENOMEM;
 	}
 
-	priv->key.type = BPF_MAP_PRIV_KEY_ALL;
+	err = bpf_map_priv_setkey(priv, term, map_name);
+	if (err)
+		return err;
 	priv->value.type = BPF_MAP_PRIV_VAL_VALUE;
 	priv->value.val = term->val.num;
 	return bpf_map__set_private(map, priv, bpf_map_priv__clear);
@@ -834,6 +881,24 @@ bpf__config_obj_map(struct bpf_object *obj,
 		goto out;
 	}
 
+	if (term->nr_indics) {
+		struct bpf_map_def def;
+
+		err = bpf_map__get_def(map, &def);
+		if (err) {
+			pr_debug("ERROR: Unable to get map definition from '%s'\n",
+				 map_name);
+			goto out;
+		}
+		for (i = 0; i < term->nr_indics; i++)
+			if (term->indics[i] >= def.max_entries) {
+				pr_debug("ERROR: index %d too large\n",
+					 (int)term->indics[i]);
+				err = -E2BIG;
+				goto out;
+			}
+	}
+
 	for (i = 0; i < ARRAY_SIZE(bpf_config_map_funcs); i++) {
 		struct bpf_config_map_func *func = &bpf_config_map_funcs[i];
 
@@ -1004,6 +1069,7 @@ int bpf__strerror_config_obj(struct bpf_object *obj __maybe_unused,
 {
 	bpf__strerror_head(err, buf, size);
 	bpf__strerror_entry(ENODEV, "Invalid config option: '%s'", term->config)
+	bpf__strerror_entry(E2BIG,  "Index in '%s' too big", term->config)
 	bpf__strerror_entry(ENOENT, "Config target in '%s' is invalid", term->config)
 	bpf__strerror_entry(EBADF,  "Map type mismatch in '%s'", term->config)
 	bpf__strerror_entry(EINVAL, "Invalid config value")
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 9f081a1..42ac1cb 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -2123,8 +2123,10 @@ void parse_events__free_terms(struct list_head *terms)
 {
 	struct parse_events_term *term, *h;
 
-	list_for_each_entry_safe(term, h, terms, list)
+	list_for_each_entry_safe(term, h, terms, list) {
+		free(term->indics);
 		free(term);
+	}
 }
 
 void parse_events_evlist_error(struct parse_events_evlist *data,
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index d4aa88e..5ba1d3e 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -71,6 +71,8 @@ enum {
 
 struct parse_events_term {
 	char *config;
+	size_t nr_indics;
+	u64 *indics;
 	union {
 		char *str;
 		u64  num;
-- 
1.8.3.4

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