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Commit daa460a8 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Ingo Molnar
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ftrace: Only allocate the ret_stack 'fp' field when needed 



This saves some memory when HAVE_FUNCTION_GRAPH_FP_TEST isn't defined.
On x86_64 with newer versions of gcc which have -mfentry, it saves 400
bytes per task.

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/5c7747d9ea7b5cb47ef0a8ce8a6cea6bf7aa94bf.1471607358.git.jpoimboe@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e4a744ef

include/linux/ftrace.h

+2 −0
Original line number Diff line number Diff line
@@ -795,7 +795,9 @@ struct ftrace_ret_stack { 
	unsigned long func;

	unsigned long long calltime;

	unsigned long long subtime;

#ifdef HAVE_FUNCTION_GRAPH_FP_TEST

	unsigned long fp;

#endif

};



/*

kernel/trace/trace_functions_graph.c

+2 −0
Original line number Diff line number Diff line
@@ -171,7 +171,9 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, 
	current->ret_stack[index].func = func;

	current->ret_stack[index].calltime = calltime;

	current->ret_stack[index].subtime = 0;

#ifdef HAVE_FUNCTION_GRAPH_FP_TEST

	current->ret_stack[index].fp = frame_pointer;

#endif

	*depth = current->curr_ret_stack;



	return 0;