Re: [PATCH 1/2] function-graph: disable when both x86_32 andoptimize for size are configured

From: Ingo Molnar
Date: Sat Jun 20 2009 - 12:25:34 EST



* Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index 4a13e5a..1eac852 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -121,6 +121,7 @@ config FUNCTION_GRAPH_TRACER
> bool "Kernel Function Graph Tracer"
> depends on HAVE_FUNCTION_GRAPH_TRACER
> depends on FUNCTION_TRACER
> + depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
> default y

Hm, nice fix, but this is a quite nasty constraint - distros like to
enable CC_OPTIMIZE_FOR_SIZE as it neatly trims the kernel's size by
about 30%.

Just in case you have not checked yet: is there no way to turn off
the specific gcc optimization that causes this? Or is it -Os itself
that does this optimization?

Ingo
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