perf cpumap: More cpu map reuse by merge.

perf_cpu_map__merge() will reuse one of its arguments if they are equal or
the other argument is NULL.

The arguments could be reused if it is known one set of values is a
subset of the other.

For example, a map of 0-1 and a map of just 0 when merged yields the map
of 0-1.

Currently a new map is created rather than adding a reference count to
the original 0-1 map.

Signed-off-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Antonov <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Alexey Bayduraev <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: German Gomez <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Fastabend <[email protected]>
Cc: John Garry <[email protected]>
Cc: KP Singh <[email protected]>
Cc: Kajol Jain <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Mathieu Poirier <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Riccardo Mancini <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Suzuki Poulouse <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yonghong Song <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
index 23701024e0c0ebe171af7469c9c2266da13ede13..384d5e076ee436ac2905c6572dbbdd0164bc2eb8 100644 (file)
--- a/tools/lib/perf/cpumap.c
+++ b/tools/lib/perf/cpumap.c
@@ -355,17 +355,12 @@ struct perf_cpu_map *perf_cpu_map__merge(struct perf_cpu_map *orig,
        int i, j, k;
        struct perf_cpu_map *merged;
 
-       if (!orig && !other)
-               return NULL;
-       if (!orig) {
-               perf_cpu_map__get(other);
-               return other;
-       }
-       if (!other)
-               return orig;
-       if (orig->nr == other->nr &&
-           !memcmp(orig->map, other->map, orig->nr * sizeof(struct perf_cpu)))
+       if (perf_cpu_map__is_subset(orig, other))
                return orig;
+       if (perf_cpu_map__is_subset(other, orig)) {
+               perf_cpu_map__put(orig);
+               return perf_cpu_map__get(other);
+       }
 
        tmp_len = orig->nr + other->nr;
        tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));