From: Peter Zijlstra <peterz@infradead.org>
To: Nick Piggin <npiggin@suse.de>
Cc: Jan Beulich <JBeulich@novell.com>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
hpa@zytor.com, linux-kernel@vger.kernel.org
Subject: Re: uses of cmpxchg/xadd in spinlock.h and rwsem.h vs. CONFIG_M386
Date: Tue, 12 May 2009 18:02:37 +0200 [thread overview]
Message-ID: <1242144157.11251.355.camel@twins> (raw)
In-Reply-To: <20090512153732.GA31131@wotan.suse.de>
On Tue, 2009-05-12 at 17:37 +0200, Nick Piggin wrote:
> On Tue, May 12, 2009 at 04:19:00PM +0100, Jan Beulich wrote:
> > While looking at a completely different issue I happened to grep for uses of
> > xadd, and it would appear to me that there got uses added that would make
> > a M386-configured SMP kernel die on an actual i386.
> >
> > Oh, for the rwsem case I see - it would use the RWSEM_GENERIC_SPINLOCK case
> > when selecting M386. But I see nothing similar for the ticket spinlocks - am
> > I overlooking something?
>
> Oh, hmm, we do actually attempt to support 386 SMP kernels... I thought
> that config wasn't allowed, but looking at the atomic.h code, it has
> ifdef fallbacks.
>
> I guess some similar hacks could be added to spinlock.h code.
Last time this came up I thought we decided i386-smp wasn't supported,
and the Kconfig files ought to be adjusted.
next prev parent reply other threads:[~2009-05-12 16:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-12 15:19 uses of cmpxchg/xadd in spinlock.h and rwsem.h vs. CONFIG_M386 Jan Beulich
2009-05-12 15:37 ` Nick Piggin
2009-05-12 15:57 ` Alan Cox
2009-05-12 16:02 ` Peter Zijlstra [this message]
2009-05-12 15:51 ` H. Peter Anvin
2009-05-12 15:57 ` Nick Piggin
2009-05-12 16:04 ` H. Peter Anvin
2009-05-12 16:16 ` Jan Beulich
2009-05-12 16:18 ` Andreas Schwab
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