linux-kernel - [PATCH v1 3/4] perf cpumap: Add "any" CPU handling to cpu_map__snprint

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Message-ID: <20251201230904.290733-3-irogers@google.com>
Date: Mon,  1 Dec 2025 15:09:03 -0800
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	James Clark <james.clark@...aro.org>, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: [PATCH v1 3/4] perf cpumap: Add "any" CPU handling to cpu_map__snprint_mask

If the perf_cpu_map is empty or is just the any CPU value, then early
return. Don't process the "any" CPU when creating the bitmap.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/cpumap.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index 89570397a4b3..a80845038a5e 100644
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -684,16 +684,21 @@ size_t cpu_map__snprint_mask(struct perf_cpu_map *map, char *buf, size_t size)
 	unsigned char *bitmap;
 	struct perf_cpu c, last_cpu = perf_cpu_map__max(map);
 
-	if (buf == NULL)
+	if (buf == NULL || size == 0)
 		return 0;
 
+	if (last_cpu.cpu < 0) {
+		buf[0] = '\0';
+		return 0;
+	}
+
 	bitmap = zalloc(last_cpu.cpu / 8 + 1);
 	if (bitmap == NULL) {
 		buf[0] = '\0';
 		return 0;
 	}
 
-	perf_cpu_map__for_each_cpu(c, idx, map)
+	perf_cpu_map__for_each_cpu_skip_any(c, idx, map)
 		bitmap[c.cpu / 8] |= 1 << (c.cpu % 8);
 
 	for (int cpu = last_cpu.cpu / 4 * 4; cpu >= 0; cpu -= 4) {
-- 
2.52.0.158.g65b55ccf14-goog