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

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Message-ID: <tip-4874fe1eeb40b403a8c9d0ddeb4d166cab3f37ba@git.kernel.org>
Date:	Fri, 15 May 2015 02:39:51 -0700
From:	tip-bot for Ingo Molnar <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	peterz@...radead.org, a.p.zijlstra@...llo.nl, aswin@...com,
	torvalds@...ux-foundation.org, brgerst@...il.com,
	paulmck@...ux.vnet.ibm.com, tglx@...utronix.de, jason.low2@...com,
	mingo@...nel.org, luto@...capital.net, hpa@...or.com,
	dave@...olabs.net, dvlasenk@...hat.com, tim.c.chen@...ux.intel.com,
	bp@...en8.de, linux-kernel@...r.kernel.org
Subject: [tip:x86/asm] x86: Pack function addresses tightly as well

Commit-ID:  4874fe1eeb40b403a8c9d0ddeb4d166cab3f37ba
Gitweb:     http://git.kernel.org/tip/4874fe1eeb40b403a8c9d0ddeb4d166cab3f37ba
Author:     Ingo Molnar <mingo@...nel.org>
AuthorDate: Fri, 10 Apr 2015 14:18:08 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
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@...hat.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Aswin Chandramouleeswaran <aswin@...com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Davidlohr Bueso <dave@...olabs.net>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Jason Low <jason.low2@...com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Tim Chen <tim.c.chen@...ux.intel.com>
Link: http://lkml.kernel.org/r/20150410121808.GA19918@gmail.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 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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