From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.suse.de (ns1.suse.de [195.135.220.2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx1.suse.de", Issuer "CAcert Class 3 Root" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 7E075DDDEF for ; Sun, 2 Nov 2008 12:42:30 +1100 (EST) Date: Sun, 2 Nov 2008 02:42:21 +0100 From: Nick Piggin To: Kumar Gala Subject: Re: [patch] powerpc: smp_wmb lwsync optimisation fix Message-ID: <20081102014221.GA13758@wotan.suse.de> References: <20081101123339.GA32055@wotan.suse.de> <02812037-F4FA-4257-8A8A-5D0E400D1FF1@kernel.crashing.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <02812037-F4FA-4257-8A8A-5D0E400D1FF1@kernel.crashing.org> Cc: paulus@samba.org, Anton Blanchard , linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sat, Nov 01, 2008 at 11:47:58AM -0500, Kumar Gala wrote: > > On Nov 1, 2008, at 7:33 AM, Nick Piggin wrote: > > >A previous change removed __SUBARCH_HAS_LWSYNC define, and replaced it > >with __powerpc64__. smp_wmb() seems to be the last place not updated. > > Uugh... no.. I missed the patch that removed __SUBARCH_HAS_LWSYNC, but > thats no good. We have LWSYNC on non-powerpc64 machines. Will go > figure out who forgets we have ppc32 machines :) I think it may have been you :) But actually, SMPWMB would need more massaging before it is suitable, by the looks of your LWSYNC define in synch.h. I don't mind, so much, about how this gets fixed. But it would be nice to fix it somehow. After the smp_rmb and smp_wmb patches, there are practically no sync instructions left in mm/ :) > > - k > > > > > > >Signed-off-by: Nick Piggin > >--- > >Index: linux-2.6/arch/powerpc/include/asm/system.h > >=================================================================== > >--- linux-2.6.orig/arch/powerpc/include/asm/system.h 2008-11-01 > >20:31:51.000000000 +1100 > >+++ linux-2.6/arch/powerpc/include/asm/system.h 2008-11-01 > >20:32:33.000000000 +1100 > >@@ -44,7 +44,7 @@ > >#define AT_VECTOR_SIZE_ARCH 6 /* entries in ARCH_DLINFO */ > >#ifdef CONFIG_SMP > > > >-#ifdef __SUBARCH_HAS_LWSYNC > >+#if defined(__powerpc64__) > ># define SMPWMB lwsync > >#else > ># define SMPWMB eieio > >_______________________________________________ > >Linuxppc-dev mailing list > >Linuxppc-dev@ozlabs.org > >https://ozlabs.org/mailman/listinfo/linuxppc-dev