From: Nick Piggin <npiggin@suse.de>
To: Kumar Gala <galak@kernel.crashing.org>
Cc: paulus@samba.org, Anton Blanchard <anton@samba.org>,
linuxppc-dev@ozlabs.org
Subject: Re: [patch] powerpc: smp_wmb lwsync optimisation fix
Date: Sun, 2 Nov 2008 02:42:21 +0100 [thread overview]
Message-ID: <20081102014221.GA13758@wotan.suse.de> (raw)
In-Reply-To: <02812037-F4FA-4257-8A8A-5D0E400D1FF1@kernel.crashing.org>
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 <npiggin@suse.de>
> >---
> >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
prev parent reply other threads:[~2008-11-02 1:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-01 12:33 [patch] powerpc: smp_wmb lwsync optimisation fix Nick Piggin
2008-11-01 13:05 ` [patch] powerpc: rmp_wmb lwsync optimisation Nick Piggin
2008-11-01 13:07 ` [rfc][patch] powerpc: replace isync with lwsync Nick Piggin
2008-11-03 5:32 ` Paul Mackerras
2008-11-03 8:31 ` Nick Piggin
2008-11-01 16:47 ` [patch] powerpc: smp_wmb lwsync optimisation fix Kumar Gala
2008-11-02 1:42 ` Nick Piggin [this message]
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