Date: Sat, 1 May 2004 04:02:20 +0200
From: Andi Kleen <ak@suse.de>
To: Andrew Morton <akpm@osdl.org>
Cc: Andi Kleen <ak@suse.de>, mikpe@csd.uu.se, linux-kernel@vger.kernel.org
Subject: Re: [BUG] 2.6.6-rc2-bk5 mm/slab.c change broke x86-64 SMP
Message-ID: <20040501020220.GD14663@wotan.suse.de>
References: <200404301611.i3UGBkdK026345@harpo.it.uu.se> <20040430112704.3dca3c4c.akpm@osdl.org> <20040501014807.GC14663@wotan.suse.de> <20040430190102.2994000e.akpm@osdl.org>
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On Fri, Apr 30, 2004 at 07:01:02PM -0700, Andrew Morton wrote:
> Andi Kleen <ak@suse.de> wrote:
> >
> > > Does this fix?
> > > 
> > > diff -puN include/asm-x86_64/processor.h~a include/asm-x86_64/processor.h
> > > --- 25/include/asm-x86_64/processor.h~a	Fri Apr 30 11:24:58 2004
> > > +++ 25-akpm/include/asm-x86_64/processor.h	Fri Apr 30 11:25:28 2004
> > > @@ -20,6 +20,8 @@
> > >  #include <asm/mmsegment.h>
> > >  #include <linux/personality.h>
> > >  
> > > +#define ARCH_MIN_TASKALIGN L1_CACHE_BYTES
> > 
> > 16 should be enough actually. The problem is the FXSAVE instruction that 
> > is used to switch the FPU state, and that only requires 16 byte alignment.
> > 
> 
> yup.  I sent Linus the patch which changes the default from 0 to
> L1_CACHE_SIZE in kernel/fork.c.  x86_64 can override that by setting
> ARCH_MIN_TASKALIGN to 16 in asm/processor.h

Ok, I will change it in my next patchkit.

For i386 it is the same - 16 should be enough.

-Andi
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