[ 02/46] Ensure that kernel_init_freeable() is not inlined into non __init code

Greg Kroah-Hartman
2013-01-24T21:14:07Z

From: Vineet Gupta <Vineet.Gupta1@synopsys.com>

commit f80b0c904da93b9ad7db2fd9823dd701932df779 upstream.

Commit d6b2123802d "make sure that we always have a return path from
kernel_execve()" reshuffled kernel_init()/init_post() to ensure that
kernel_execve() has a caller to return to.

It removed __init annotation for kernel_init() and introduced/calls a
new routine kernel_init_freeable(). Latter however is inlined by any
reasonable compiler (ARC gcc 4.4 in this case), causing slight code
bloat.

This patch forces kernel_init_freeable() as noinline reducing the .text

bloat-o-meter vmlinux vmlinux_new
add/remove: 1/0 grow/shrink: 0/1 up/down: 374/-334 (40)
function old new delta
kernel_init_freeable - 374 +374 (.init.text)
kernel_init 628 294 -334 (.text)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
init/main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/init/main.c
+++ b/init/main.c
@@ -800,7 +800,7 @@ static int run_init_process(const char *
return kernel_execve(init_filename, argv_init, envp_init);
}

-static void __init kernel_init_freeable(void);
+static noinline void __init kernel_init_freeable(void);

static int __ref kernel_init(void *unused)
{
@@ -844,7 +844,7 @@ static int __ref kernel_init(void *unuse
"See Linux Documentation/init.txt for guidance.");
}

-static void __init kernel_init_freeable(void)
+static noinline void __init kernel_init_freeable(void)
{
/*
* Wait until kthreadd is all set-up.