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authorJosh Poimboeuf <[email protected]>2016-08-19 06:52:56 -0500
committerIngo Molnar <[email protected]>2016-08-24 12:15:14 +0200
commitdaa460a88c09b26b68e8b017de589c217e901afb (patch)
treed57e0a053fac1bc06cfd29194bc578bc5b68d88c /kernel/trace/trace_functions_graph.c
parente4a744ef2fef5c803348b650a3a2d01da7797a9b (diff)
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.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <[email protected]>
Diffstat (limited to 'kernel/trace/trace_functions_graph.c')
-rw-r--r--kernel/trace/trace_functions_graph.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index fc173cd9fbfd..0e03ed0eac68 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;