From 092a38565ed87cbda6fe7dd16c742df6f907483e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 5 May 2025 17:21:13 -0400 Subject: ring-buffer: Add ring_buffer_record_is_on_cpu() Add the function ring_buffer_record_is_on_cpu() that returns true if the ring buffer for a give CPU is writable and false otherwise. Also add tracer_tracing_is_on_cpu() to return if the ring buffer for a given CPU is writeable for a given trace_array. Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Link: https://lore.kernel.org/20250505212236.059853898@goodmis.org Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ring_buffer.c | 18 ++++++++++++++++++ kernel/trace/trace.h | 15 +++++++++++++++ 2 files changed, 33 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index c0f877d39a24..1ca482955dae 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -4882,6 +4882,24 @@ bool ring_buffer_record_is_set_on(struct trace_buffer *buffer) return !(atomic_read(&buffer->record_disabled) & RB_BUFFER_OFF); } +/** + * ring_buffer_record_is_on_cpu - return true if the ring buffer can write + * @buffer: The ring buffer to see if write is enabled + * @cpu: The CPU to test if the ring buffer can write too + * + * Returns true if the ring buffer is in a state that it accepts writes + * for a particular CPU. + */ +bool ring_buffer_record_is_on_cpu(struct trace_buffer *buffer, int cpu) +{ + struct ring_buffer_per_cpu *cpu_buffer; + + cpu_buffer = buffer->buffers[cpu]; + + return ring_buffer_record_is_set_on(buffer) && + !atomic_read(&cpu_buffer->record_disabled); +} + /** * ring_buffer_record_disable_cpu - stop all writes into the cpu_buffer * @buffer: The ring buffer to stop writes to. diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 74f1fe5788d4..69c1ecfb2290 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -673,6 +673,21 @@ struct dentry *trace_create_file(const char *name, void *data, const struct file_operations *fops); + +/** + * tracer_tracing_is_on_cpu - show real state of ring buffer enabled on for a cpu + * @tr : the trace array to know if ring buffer is enabled + * @cpu: The cpu buffer to check if enabled + * + * Shows real state of the per CPU buffer if it is enabled or not. + */ +static inline bool tracer_tracing_is_on_cpu(struct trace_array *tr, int cpu) +{ + if (tr->array_buffer.buffer) + return ring_buffer_record_is_on_cpu(tr->array_buffer.buffer, cpu); + return false; +} + int tracing_init_dentry(void); struct ring_buffer_event; -- cgit v1.2.3