libperf cpumap: Grow array of read CPUs in smaller increments

JIRA: https://issues.redhat.com/browse/RHEL-73893

upstream
========
commit bfb9467
Author: Ian Rogers <irogers@google.com>
Date: Thu Dec 5 20:40:35 2024 -0800

description
===========
Instead of growing the array by 2048, grow by the larger of the current
range or 16.

As ranges are typical for things like the online CPUs this will mean a
single allocation happens.

While uncore CPU maps will grow 16 at a time which is a value that is
generous except say on large servers.

    Reviewed-by: Leo Yan <leo.yan@arm.com>
    Signed-off-by: Ian Rogers <irogers@google.com>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: Ben Gainey <ben.gainey@arm.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: James Clark <james.clark@linaro.org>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: Kan Liang <kan.liang@linux.intel.com>
    Cc: Kyle Meyer <kyle.meyer@hpe.com>
    Cc: Mark Rutland <mark.rutland@arm.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Link: https://lore.kernel.org/r/20241206044035.1062032-9-irogers@google.com
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Michael Petlan <mpetlan@redhat.com>

Author: rfmvh

tools/lib/perf/cpumap.c

@@ -212,7 +212,7 @@ struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list)
 					goto invalid;
 
 			if (nr_cpus == max_entries) {
-				max_entries += MAX_NR_CPUS;
+				max_entries += max(end_cpu - start_cpu + 1, 16UL);
 				tmp = realloc(tmp_cpus, max_entries * sizeof(struct perf_cpu));
 				if (tmp == NULL)
 					goto invalid;
@@ -226,14 +226,15 @@ struct perf_cpu_map *perf_cpu_map__new(const char *cpu_list)
 		cpu_list = p;
 	}
 
-	if (nr_cpus > 0)
+	if (nr_cpus > 0) {
 		cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
-	else if (*cpu_list != '\0') {
+	} else if (*cpu_list != '\0') {
 		pr_warning("Unexpected characters at end of cpu list ('%s'), using online CPUs.",
 			   cpu_list);
 		cpus = perf_cpu_map__new_online_cpus();
-	} else
+	} else {
 		cpus = perf_cpu_map__new_any_cpu();
+	}
 invalid:
 	free(tmp_cpus);
 out: