Messages in this thread Patch in this message | | | From | Vineet Gupta <> | Subject | [PATCH RESEND] Ensure that kernel_init_freeable() is not inlined into non __init code | Date | Fri, 21 Dec 2012 12:25:44 +0530 |
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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 <vgupta@synopsys.com> CC: Rusty Russell <rusty@rustcorp.com.au> CC: Jim Cromie <jim.cromie@gmail.com> CC: Andrew Morton <akpm@linux-foundation.org> CC: "H. Peter Anvin" <hpa@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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