Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752125Ab1C0B5Y (ORCPT ); Sat, 26 Mar 2011 21:57:24 -0400 Received: from smtp109.prem.mail.ac4.yahoo.com ([76.13.13.92]:32947 "HELO smtp109.prem.mail.ac4.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751786Ab1C0B5X (ORCPT ); Sat, 26 Mar 2011 21:57:23 -0400 X-Yahoo-SMTP: _Dag8S.swBC1p4FJKLCXbs8NQzyse1SYSgnAbY0- X-YMail-OSG: IeT7RlUVM1mnHmdqjK4F5aETiYkxZ6myZH.3QrBzLRWJrBA yBZIFk2RZ7BfpKmbB33saBvSf1pUj6k7o80n1f2e1Z8skYsa2zwIEh13DXfi fYSa1L_cKgvK.aVj1N7svlPsY3iyHdXdeuMGWzO8ccWRjvD07LB6NLNYE1or DhkY3qNYFTbJfUd6NEXq54rTN1JdIL2n9Egs0PzIfpVGblwIvjblNu.kFjBh 1CR4PTxVPicqZKo6Ap_nLBrqsTAnt7ezq5yDaUZZLQgcrpvWbo.boRGJLIUm E41FRClvj6.GqbDigMzCigJPLTobtMLXZmYmpll_zDJu3my5pf9SR80UKwrQ c1eY- X-Yahoo-Newman-Property: ymail-3 Date: Sat, 26 Mar 2011 20:57:18 -0500 (CDT) From: Christoph Lameter X-X-Sender: cl@router.home To: Linus Torvalds cc: Eric Dumazet , Ingo Molnar , Pekka Enberg , Thomas Gleixner , akpm@linux-foundation.org, tj@kernel.org, npiggin@kernel.dk, rientjes@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] slub: Disable the lockless allocator In-Reply-To: Message-ID: References: <20110324142146.GA11682@elte.hu> <20110324172653.GA28507@elte.hu> <20110324185258.GA28370@elte.hu> <20110324192247.GA5477@elte.hu> <20110326112725.GA28612@elte.hu> <20110326114736.GA8251@elte.hu> <1301161507.2979.105.camel@edumazet-laptop> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: MULTIPART/Mixed; BOUNDARY=0015177407b69c6eb6049f6a184f Content-ID: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5478 Lines: 140 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --0015177407b69c6eb6049f6a184f Content-Type: TEXT/PLAIN; CHARSET=US-ASCII Content-ID: But then the same fix must also be used in the asm code or the fallback (turns out that the fallback is always used in kmem_cache_init since the instruction patching comes later). Patch boots fine both in UP and SMP mode Subject: percpu: Omit segment prefix in the UP case for cmpxchg_double Omit the segment prefix in the UP case. GS is not used then and we will generate segfaults if cmpxchg16b is used otherwise. Signed-off-by: Linus Torvalds Signed-off-by: Christoph Lameter arch/x86/include/asm/percpu.h | 10 ++++++---- 1 files changed, 6 insertions(+), 4 deletions(-) Index: linux-2.6/arch/x86/include/asm/percpu.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/percpu.h 2011-03-26 20:43:03.994089001 -0500 +++ linux-2.6/arch/x86/include/asm/percpu.h 2011-03-26 20:43:22.414089004 -0500 @@ -45,7 +45,7 @@ #include #ifdef CONFIG_SMP -#define __percpu_arg(x) "%%"__stringify(__percpu_seg)":%P" #x +#define __percpu_prefix "%%"__stringify(__percpu_seg)":" #define __my_cpu_offset percpu_read(this_cpu_off) /* @@ -62,9 +62,11 @@ (typeof(*(ptr)) __kernel __force *)tcp_ptr__; \ }) #else -#define __percpu_arg(x) "%P" #x +#define __percpu_prefix "" #endif +#define __percpu_arg(x) __percpu_prefix "%P" #x + /* * Initialized pointers to per-cpu variables needed for the boot * processor need to use these macros to get the proper address @@ -516,11 +518,11 @@ typeof(o2) __n2 = n2; \ typeof(o2) __dummy; \ alternative_io("call this_cpu_cmpxchg16b_emu\n\t" P6_NOP4, \ - "cmpxchg16b %%gs:(%%rsi)\n\tsetz %0\n\t", \ + "cmpxchg16b " __percpu_prefix "(%%rsi)\n\tsetz %0\n\t", \ X86_FEATURE_CX16, \ ASM_OUTPUT2("=a"(__ret), "=d"(__dummy)), \ "S" (&pcp1), "b"(__n1), "c"(__n2), \ - "a"(__o1), "d"(__o2)); \ + "a"(__o1), "d"(__o2) : "memory"); \ __ret; \ }) Index: linux-2.6/arch/x86/lib/cmpxchg16b_emu.S =================================================================== --- linux-2.6.orig/arch/x86/lib/cmpxchg16b_emu.S 2011-03-26 20:43:57.384089004 -0500 +++ linux-2.6/arch/x86/lib/cmpxchg16b_emu.S 2011-03-26 20:48:42.684088999 -0500 @@ -10,6 +10,12 @@ #include #include +#ifdef CONFIG_SMP +#define SEG_PREFIX %gs: +#else +#define SEG_PREFIX +#endif + .text /* @@ -37,13 +43,13 @@ pushf cli - cmpq %gs:(%rsi), %rax + cmpq SEG_PREFIX(%rsi), %rax jne not_same - cmpq %gs:8(%rsi), %rdx + cmpq SEG_PREFIX 8(%rsi), %rdx jne not_same - movq %rbx, %gs:(%rsi) - movq %rcx, %gs:8(%rsi) + movq %rbx, SEG_PREFIX(%rsi) + movq %rcx, SEG_PREFIX 8(%rsi) popf mov $1, %al --0015177407b69c6eb6049f6a184f Content-Type: TEXT/X-PATCH; CHARSET=US-ASCII; NAME=patch.diff Content-Transfer-Encoding: BASE64 Content-ID: Content-Description: Content-Disposition: ATTACHMENT; FILENAME=patch.diff IGFyY2gveDg2L2luY2x1ZGUvYXNtL3BlcmNwdS5oIHwgICAxMCArKysrKystLS0tCiAxIGZpbGVz IGNoYW5nZWQsIDYgaW5zZXJ0aW9ucygrKSwgNCBkZWxldGlvbnMoLSkKCmRpZmYgLS1naXQgYS9h cmNoL3g4Ni9pbmNsdWRlL2FzbS9wZXJjcHUuaCBiL2FyY2gveDg2L2luY2x1ZGUvYXNtL3BlcmNw dS5oCmluZGV4IGEwOWUxZjAuLmQ0NzViNDMgMTAwNjQ0Ci0tLSBhL2FyY2gveDg2L2luY2x1ZGUv YXNtL3BlcmNwdS5oCisrKyBiL2FyY2gveDg2L2luY2x1ZGUvYXNtL3BlcmNwdS5oCkBAIC00NSw3 ICs0NSw3IEBACiAjaW5jbHVkZSA8bGludXgvc3RyaW5naWZ5Lmg+CiAKICNpZmRlZiBDT05GSUdf U01QCi0jZGVmaW5lIF9fcGVyY3B1X2FyZyh4KQkJIiUlIl9fc3RyaW5naWZ5KF9fcGVyY3B1X3Nl ZykiOiVQIiAjeAorI2RlZmluZSBfX3BlcmNwdV9wcmVmaXgJCSIlJSJfX3N0cmluZ2lmeShfX3Bl cmNwdV9zZWcpIjoiCiAjZGVmaW5lIF9fbXlfY3B1X29mZnNldAkJcGVyY3B1X3JlYWQodGhpc19j cHVfb2ZmKQogCiAvKgpAQCAtNjIsOSArNjIsMTEgQEAKIAkodHlwZW9mKCoocHRyKSkgX19rZXJu ZWwgX19mb3JjZSAqKXRjcF9wdHJfXzsJXAogfSkKICNlbHNlCi0jZGVmaW5lIF9fcGVyY3B1X2Fy Zyh4KQkJIiVQIiAjeAorI2RlZmluZSBfX3BlcmNwdV9wcmVmaXgJCSIiCiAjZW5kaWYKIAorI2Rl ZmluZSBfX3BlcmNwdV9hcmcoeCkJCV9fcGVyY3B1X3ByZWZpeCAiJVAiICN4CisKIC8qCiAgKiBJ bml0aWFsaXplZCBwb2ludGVycyB0byBwZXItY3B1IHZhcmlhYmxlcyBuZWVkZWQgZm9yIHRoZSBi b290CiAgKiBwcm9jZXNzb3IgbmVlZCB0byB1c2UgdGhlc2UgbWFjcm9zIHRvIGdldCB0aGUgcHJv cGVyIGFkZHJlc3MKQEAgLTUxNiwxMSArNTE4LDExIEBAIGRvIHsJCQkJCQkJCQlcCiAJdHlwZW9m KG8yKSBfX24yID0gbjI7CQkJCQkJXAogCXR5cGVvZihvMikgX19kdW1teTsJCQkJCQlcCiAJYWx0 ZXJuYXRpdmVfaW8oImNhbGwgdGhpc19jcHVfY21weGNoZzE2Yl9lbXVcblx0IiBQNl9OT1A0LAlc Ci0JCSAgICAgICAiY21weGNoZzE2YiAlJWdzOiglJXJzaSlcblx0c2V0eiAlMFxuXHQiLAlcCisJ CSAgICAgICAiY21weGNoZzE2YiAiIF9fcGVyY3B1X3ByZWZpeCAiKCUlcnNpKVxuXHRzZXR6ICUw XG5cdCIsCVwKIAkJICAgICAgIFg4Nl9GRUFUVVJFX0NYMTYsCQkJCVwKIAkJICAgICAgIEFTTV9P VVRQVVQyKCI9YSIoX19yZXQpLCAiPWQiKF9fZHVtbXkpKSwJCVwKIAkJICAgICAgICJTIiAoJnBj cDEpLCAiYiIoX19uMSksICJjIihfX24yKSwJCVwKLQkJICAgICAgICJhIihfX28xKSwgImQiKF9f bzIpKTsJCQkJXAorCQkgICAgICAgImEiKF9fbzEpLCAiZCIoX19vMikgOiAibWVtb3J5Iik7CQlc CiAJX19yZXQ7CQkJCQkJCQlcCiB9KQogCg== --0015177407b69c6eb6049f6a184f-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/