Commit-ID: daa460a88c09b26b68e8b017de589c217e901afb Gitweb: http://git.kernel.org/tip/daa460a88c09b26b68e8b017de589c217e901afb Author: Josh Poimboeuf <[email protected]> AuthorDate: Fri, 19 Aug 2016 06:52:56 -0500 Committer: Ingo Molnar <[email protected]> CommitDate: Wed, 24 Aug 2016 12:15:14 +0200
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: Josh Poimboeuf <[email protected]> Acked-by: Steven Rostedt <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Byungchul Park <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Kees Cook <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Nilay Vaish <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/5c7747d9ea7b5cb47ef0a8ce8a6cea6bf7aa94bf.1471607358.git.jpoim...@redhat.com Signed-off-by: Ingo Molnar <[email protected]> --- include/linux/ftrace.h | 2 ++ kernel/trace/trace_functions_graph.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 7d565af..4ad9ccc 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -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 }; /* diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index fc173cd..0e03ed0 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -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;
