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)
Just for documentation, here's what Al's orig commit did.
Orig
----
THREAD __init kernel_init()
smp_init()
...
open("/dev/console")
init_post() --> forced to be noinline
return 0;
init_post()
free_initmem() --> reaps caller kernel_init()
run_init_process("/init")
kernel_execve
New
---
THREAD kernel_init()
kernel_init_freeable() --> __init tagged
smp_init()
...
open("/dev/console")
free_initmem() --> reaps kernel_init_freeable()
run_init_process "init"
kernel_execve
Signed-off-by: Vineet Gupta <vgu...@synopsys.com>
CC: Rusty Russell <ru...@rustcorp.com.au>
CC: Jim Cromie <jim.cro...@gmail.com>
CC: Andrew Morton <a...@linux-foundation.org>
CC: "H. Peter Anvin" <h...@linux.intel.com>
CC: linux-kernel@vger.kernel.org
---
init/main.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/init/main.c b/init/main.c
index 85d69df..92d728a 100644
--- a/init/main.c
+++ b/init/main.c
@@ -802,7 +802,7 @@ static int run_init_process(const char *init_filename)
(const char __user *const __user *)envp_init);
}
-static void __init kernel_init_freeable(void);
+static noinline void __init kernel_init_freeable(void);
static int __ref kernel_init(void *unused)
{
@@ -845,7 +845,7 @@ static int __ref kernel_init(void *unused)
"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.
--
1.7.4.1
--
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