[tip:x86/asm] x86: Pack function addresses tightly as well

[tip-bot for Ingo Molnar]

Commit-ID:  4874fe1eeb40b403a8c9d0ddeb4d166cab3f37ba
Gitweb:     http://git.kernel.org/tip/4874fe1eeb40b403a8c9d0ddeb4d166cab3f37ba
Author:     Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate: Fri, 10 Apr 2015 14:18:08 +0200
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 15 May 2015 11:05:21 +0200

x86: Pack function addresses tightly as well

So as per the arguments laid out in:

  be6cb02779ca ("x86: Align jump targets to 1-byte boundaries")

We can pack function addresses tightly as well:

     text	   data	    bss	     dec	 filename
 12566391	1617840	1089536	15273767	 vmlinux.align.16-byte
 12224951	1617840	1089536	14932327	 vmlinux.align.1-byte
 11976567	1617840	1089536	14683943	 vmlinux.align.1-byte.funcs-1-byte

Which brings another 2% reduction in the defconfig kernel's
code size.

Acked-by: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Aswin Chandramouleeswaran <aswin@xxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Jason Low <jason.low2@xxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20150410121808.GA19918@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index ca17e5f..5c7edf9 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -80,6 +80,9 @@ else
         # Align jump targets to 1 byte, not the default 16 bytes:
         KBUILD_CFLAGS += -falign-jumps=1
 
+        # Pack functions tightly as well:
+        KBUILD_CFLAGS += -falign-functions=1
+
         # Don't autogenerate traditional x87 instructions
         KBUILD_CFLAGS += $(call cc-option,-mno-80387)
         KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
--
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