linux-kernel - [PATCH v4 5/7] perf/util/machine: Replace MAX_NR_CPUS with nr_cpus

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Message-Id: <20190827214352.94272-6-meyerk@stormcage.eag.rdlabs.hpecorp.net>
Date:   Tue, 27 Aug 2019 16:43:50 -0500
From:   Kyle Meyer <meyerk@....com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Kyle Meyer <meyerk@....com>, Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        linux-kernel@...r.kernel.org,
        Russ Anderson <russ.anderson@....com>,
        Kyle Meyer <kyle.meyer@....com>
Subject: [PATCH v4 5/7] perf/util/machine: Replace MAX_NR_CPUS with nr_cpus_online

nr_cpus, the number of CPUs online during a record session bound by
MAX_NR_CPUS, can be used as a dynamic alternative for MAX_NR_CPUS in
__machine__synthesize_threads and machine__set_current_tid.

Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: linux-kernel@...r.kernel.org
Cc: Russ Anderson <russ.anderson@....com>
Signed-off-by: Kyle Meyer <kyle.meyer@....com>
---
 tools/perf/util/machine.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 5734460fc89e..194b9ec5f88b 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2616,7 +2616,9 @@ int __machine__synthesize_threads(struct machine *machine, struct perf_tool *too
 
 pid_t machine__get_current_tid(struct machine *machine, int cpu)
 {
-	if (cpu < 0 || cpu >= MAX_NR_CPUS || !machine->current_tid)
+	int nr_cpus = min(machine->env->nr_cpus_online, MAX_NR_CPUS);
+
+	if (cpu < 0 || cpu >= nr_cpus || !machine->current_tid)
 		return -1;
 
 	return machine->current_tid[cpu];
@@ -2626,6 +2628,7 @@ int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid,
 			     pid_t tid)
 {
 	struct thread *thread;
+	int nr_cpus = min(machine->env->nr_cpus_online, MAX_NR_CPUS);
 
 	if (cpu < 0)
 		return -EINVAL;
@@ -2633,14 +2636,14 @@ int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid,
 	if (!machine->current_tid) {
 		int i;
 
-		machine->current_tid = calloc(MAX_NR_CPUS, sizeof(pid_t));
+		machine->current_tid = calloc(nr_cpus, sizeof(pid_t));
 		if (!machine->current_tid)
 			return -ENOMEM;
-		for (i = 0; i < MAX_NR_CPUS; i++)
+		for (i = 0; i < nr_cpus; i++)
 			machine->current_tid[i] = -1;
 	}
 
-	if (cpu >= MAX_NR_CPUS) {
+	if (cpu >= nr_cpus) {
 		pr_err("Requested CPU %d too large. ", cpu);
 		pr_err("Consider raising MAX_NR_CPUS\n");
 		return -EINVAL;
-- 
2.12.3