From: Vincent Whitchurch <[email protected]> This comment describes the behaviour before commit 2a820bf74918 ("tracing: Use percpu stack trace buffer more intelligently"). Since that commit, interrupts and NMIs do use the per-cpu stacks so the comment is no longer correct. Remove it.
(Note that the FTRACE_STACK_SIZE mentioned in the comment has never existed, it probably should have said FTRACE_STACK_ENTRIES.) Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Vincent Whitchurch <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]> --- kernel/trace/trace.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4aab712f9567..dbcacdd56b02 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2930,12 +2930,6 @@ static void __ftrace_trace_stack(struct trace_buffer *buffer, skip++; #endif - /* - * Since events can happen in NMIs there's no safe way to - * use the per cpu ftrace_stacks. We reserve it and if an interrupt - * or NMI comes in, it will just have to use the default - * FTRACE_STACK_SIZE. - */ preempt_disable_notrace(); stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1; -- 2.26.2
