Commit-ID: daa460a88c09b26b68e8b017de589c217e901afb
Gitweb: http://git.kernel.org/tip/daa460a88c09b26b68e8b017de589c217e901afb
Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Fri, 19 Aug 2016 06:52:56 -0500
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
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 <jpoimboe@xxxxxxxxxx>
Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Byungchul Park <byungchul.park@xxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Nilay Vaish <nilayvaish@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/5c7747d9ea7b5cb47ef0a8ce8a6cea6bf7aa94bf.1471607358.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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;
--
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