Messages in this thread Patch in this message | | | Date | Fri, 26 May 2023 20:43:19 -0700 | Subject | [PATCH v1 1/4] perf sched: Avoid large stack allocations | From | Ian Rogers <> |
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Commit 5ded57ac1bdb ("perf inject: Remove static variables") moved static variables to local, however, in this case 3 MAX_CPUS (4096) sized arrays were moved onto the stack making the stack frame quite large. Avoid the stack usage by dynamically allocating the arrays.
Signed-off-by: Ian Rogers <irogers@google.com> --- tools/perf/builtin-sched.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index cc4ba506e119..2aeb3c8ac396 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -193,8 +193,8 @@ struct perf_sched { * weird events, such as a task being switched away that is not current. */ struct perf_cpu max_cpu; - u32 curr_pid[MAX_CPUS]; - struct thread *curr_thread[MAX_CPUS]; + u32 *curr_pid; + struct thread **curr_thread; char next_shortname1; char next_shortname2; unsigned int replay_repeat; @@ -224,7 +224,7 @@ struct perf_sched { u64 run_avg; u64 all_runtime; u64 all_count; - u64 cpu_last_switched[MAX_CPUS]; + u64 *cpu_last_switched; struct rb_root_cached atom_root, sorted_atom_root, merged_atom_root; struct list_head sort_list, cmp_pid; bool force; @@ -3599,7 +3599,22 @@ int cmd_sched(int argc, const char **argv) mutex_init(&sched.start_work_mutex); mutex_init(&sched.work_done_wait_mutex); - for (i = 0; i < ARRAY_SIZE(sched.curr_pid); i++) + sched.curr_thread = calloc(MAX_CPUS, sizeof(*sched.curr_thread)); + if (!sched.curr_thread) { + ret = -ENOMEM; + goto out; + } + sched.cpu_last_switched = calloc(MAX_CPUS, sizeof(*sched.cpu_last_switched)); + if (!sched.cpu_last_switched) { + ret = -ENOMEM; + goto out; + } + sched.curr_pid = malloc(MAX_CPUS * sizeof(*sched.curr_pid)); + if (!sched.curr_pid) { + ret = -ENOMEM; + goto out; + } + for (i = 0; i < MAX_CPUS; i++) sched.curr_pid[i] = -1; argc = parse_options_subcommand(argc, argv, sched_options, sched_subcommands, @@ -3668,6 +3683,9 @@ int cmd_sched(int argc, const char **argv) } out: + free(sched.curr_pid); + free(sched.cpu_last_switched); + free(sched.curr_thread); mutex_destroy(&sched.start_work_mutex); mutex_destroy(&sched.work_done_wait_mutex); -- 2.41.0.rc0.172.g3f132b7071-goog
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