From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 0A27D8D0040 for ; Sat, 26 Mar 2011 15:50:00 -0400 (EDT) Date: Sat, 26 Mar 2011 14:49:56 -0500 (CDT) From: Christoph Lameter 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> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Eric Dumazet Cc: Ingo Molnar , Pekka Enberg , Thomas Gleixner , torvalds@linux-foundation.org, akpm@linux-foundation.org, tj@kernel.org, npiggin@kernel.dk, rientjes@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Sat, 26 Mar 2011, Christoph Lameter wrote: > Tejun: Whats going on there? I should be getting offsets into the per cpu > area and not kernel addresses. Its a UP kernel running on dual Athlon. So its okay ... Argh.... The following patch fixes it by using the fallback code for cmpxchg_double: Subject: per_cpu: Fixup cmpxchg_double for !SMP cmpxchg_double should only be provided for SMP. In the UP case the GS register is not defined and the function will fail. Signed-off-by: Christoph Lameter Index: linux-2.6/arch/x86/include/asm/percpu.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/percpu.h 2011-03-26 11:11:19.175244998 -0500 +++ linux-2.6/arch/x86/include/asm/percpu.h 2011-03-26 14:45:29.254088998 -0500 @@ -507,6 +507,7 @@ * it in software. The address used in the cmpxchg16 instruction must be * aligned to a 16 byte boundary. */ +#ifdef CONFIG_SMP #define percpu_cmpxchg16b_double(pcp1, o1, o2, n1, n2) \ ({ \ char __ret; \ @@ -529,6 +530,7 @@ #define irqsafe_cpu_cmpxchg_double_8(pcp1, pcp2, o1, o2, n1, n2) percpu_cmpxchg16b_double(pcp1, o1, o2, n1, n2) #endif +#endif /* This is not atomic against other CPUs -- CPU preemption needs to be off */ #define x86_test_and_clear_bit_percpu(bit, var) \ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org