[PATCH 25/35] perf machine: Use realloc_array_as_needed() in machine__set_current_tid()

Adrian Hunter
2022-07-11T10:13:55Z

Prepare machine__set_current_tid() for use with guest machines that do
not currently have a machine->env->nr_cpus_avail value by making use of
realloc_array_as_needed().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/perf/util/machine.c | 26 +++++++-------------------
tools/perf/util/machine.h | 1 +
2 files changed, 8 insertions(+), 19 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 009061852808..27d1a38f44c3 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -3174,9 +3174,7 @@ int machines__for_each_thread(struct machines *machines,

pid_t machine__get_current_tid(struct machine *machine, int cpu)
{
- int nr_cpus = min(machine->env->nr_cpus_avail, MAX_NR_CPUS);
-
- if (cpu < 0 || cpu >= nr_cpus || !machine->current_tid)
+ if (cpu < 0 || (size_t)cpu >= machine->current_tid_sz)
return -1;

return machine->current_tid[cpu];
@@ -3186,26 +3184,16 @@ 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_avail, MAX_NR_CPUS);
+ const pid_t init_val = -1;

if (cpu < 0)
return -EINVAL;

- if (!machine->current_tid) {
- int i;
-
- machine->current_tid = calloc(nr_cpus, sizeof(pid_t));
- if (!machine->current_tid)
- return -ENOMEM;
- for (i = 0; i < nr_cpus; i++)
- machine->current_tid[i] = -1;
- }
-
- if (cpu >= nr_cpus) {
- pr_err("Requested CPU %d too large. ", cpu);
- pr_err("Consider raising MAX_NR_CPUS\n");
- return -EINVAL;
- }
+ if (realloc_array_as_needed(machine->current_tid,
+ machine->current_tid_sz,
+ (unsigned int)cpu,
+ &init_val))
+ return -ENOMEM;

machine->current_tid[cpu] = tid;

diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index d40b23c71420..609e24e329d1 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -57,6 +57,7 @@ struct machine {
struct map *vmlinux_map;
u64 kernel_start;
pid_t *current_tid;
+ size_t current_tid_sz;
union { /* Tool specific area */
void *priv;
u64 db_id;
--
2.25.1