On 2015/10/17 18:48, Wang Nan wrote:
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 <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Brendan Gregg <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: David Ahern <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kaixu Xia <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Zefan Li <[email protected]>
Cc: [email protected]
---
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;
+ }
+ }
This for-loop has a potential problem that, if perf's user want to
set a very big array using indices, for example:
# perf record -e
mybpf.c/maps:mymap:values[1,2,3,10-100000,200000-400000]=3/
mybpf.c/maps:mymap:values[100000-200000]=3/ ...
Perf would alloc nearly 300000 slots for indices array, consume too much
memory.
I will fix this problem by reinterprete indices array, makes negative
value represent range start and use next slot to store range size. For
example, the above perf cmdline can be converted to:
{1,2,3,-10, 99991,-200000,200001} and {-100000,100001}.
Thank you.
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