# \[PATCH v8 15/21\] tracing/remotes: Use ring\_buffer\_capacity() in trace\_remote\_has\_cpu() - From: Vincent Donnefort \ - Date: 2026-11-06 18:08:02 - List: linux-trace-kernel - Page: https://ratatoskr.run/linux-trace-kernel/2026/11/17880573 - Thread: https://ratatoskr.run/linux-trace-kernel/2026/11/17880557/t.md ```text trace_remote_has_cpu() calls ring_buffer_poll_remote() only to check if a CPU is in the trace_buffer cpumask, needlessly polling the meta-page and waking up readers. Use ring_buffer_capacity() instead to check CPU membership without taking reader_lock or triggering wakeups. Signed-off-by: Vincent Donnefort --- kernel/trace/trace_remote.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c index 3dbb4912dbd6..276bf94e837b 100644 --- a/kernel/trace/trace_remote.c +++ b/kernel/trace/trace_remote.c @@ -351,7 +351,7 @@ static bool trace_remote_has_cpu(struct trace_remote *remote, int cpu) if (cpu == RING_BUFFER_ALL_CPUS) return true; - return ring_buffer_poll_remote(remote->trace_buffer, cpu) == 0; + return ring_buffer_capacity(remote->trace_buffer, cpu) > 0; } static void __free_ring_buffer_iter(struct trace_remote_iterator *iter, int cpu) -- 2.56.0.455.g6c5a503b38-goog ```