[PATCH] tracing: Ensure optimized hashing works
From: Michal Koutný <mkoutny@suse.com>
Date: 2025-09-23 16:59:20
Also in:
lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
If ever PID_MAX_DEFAULT changes, it must be compatible with tracing hashmaps assumptions. Link: https://lore.kernel.org/r/20240409110126.651e94cb@gandalf.local.home/ (local) Signed-off-by: Michal Koutný <mkoutny@suse.com> --- kernel/trace/trace_sched_switch.c | 2 ++ 1 file changed, 2 insertions(+) Drive-by flushing an old idea. Take it or leave it.
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index cb49f7279dc80..aabae7daaac91 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c@@ -243,6 +243,8 @@ int trace_create_savedcmd(void) int trace_save_cmdline(struct task_struct *tsk) { unsigned tpid, idx; + /* so that map_pid_to_cmdline indexing is efficient */ + BUILD_BUG_ON(!is_power_of_2(PID_MAX_DEFAULT)); /* treat recording of idle task as a success */ if (!tsk->pid)
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2.51.0