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From: "Martin J. Bligh" <Martin.Bligh@us.ibm.com>
To: paulus@samba.org, Peter Rival <frival@zk3.dec.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	torvalds@transmeta.com, linux-kernel@vger.kernel.org,
	trini@kernel.crashing.org, benh@kernel.crashing.org
Subject: Re: [PATCH] change name of rep_nop
Date: Fri, 05 Oct 2001 16:54:06 -0700	[thread overview]
Message-ID: <1573466920.1002300846@mbligh.des.sequent.com> (raw)
In-Reply-To: <15294.16913.2117.383987@cargo.ozlabs.ibm.com>

>> You also need to move the call to smp_boot_cpus() below the 
>> clear_bit(...) line in smp_init().  Without it, my Wildfire doesn't get 
> 
> No, that won't work for me, because cpu_online_map is set by
> smp_boot_cpus(), at least on PPC (in fact each CPU sets its bit in
> cpu_online_map as it spins up).
> 
> There shouldn't be a race on x86 at all, because the secondary
> processors don't call init_idle until after they see that the primary
> cpu has call smp_commence.  (There is currently a race on PPC since we
> call init_idle before waiting for smp_commence, but that would not be
> your problem.)

There *is* a race on x86 - the problem is that the primary cpu can 
get to reschedule_idle before the secondarys have done init_idle.
I'm not claiming the way I fixed it is beautiful, but the race definitely
exists (I hit it) and the patch makes the problem go away. 

Sounds like rep_nop was the wrong way to spin - aplogies.

Martin.


  reply	other threads:[~2001-10-05 23:58 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-10-05 10:46 Paul Mackerras
2001-10-05 14:37 ` Alan Cox
2001-10-05 18:06   ` Peter Rival
2001-10-05 23:28   ` Paul Mackerras
2001-10-05 23:54     ` Martin J. Bligh [this message]
2001-10-06  1:40     ` Paul Mackerras
2001-10-08 19:27       ` Peter Rival
2001-10-08 22:36       ` David Woodhouse
2001-10-08 22:49         ` Alan Cox
2001-10-08 23:06         ` David Woodhouse
2001-10-08 23:42           ` David Woodhouse
2001-10-08 23:46           ` David S. Miller
2001-10-08 23:08         ` David S. Miller
2001-10-08 23:46         ` Linus Torvalds
2001-10-09  0:03           ` David Woodhouse
2001-10-08 22:46       ` David S. Miller
2001-10-08 23:16         ` Alan Cox
2001-10-08 23:24           ` Dave Jones
2001-10-08 23:33             ` Alan Cox
2001-10-09  5:01             ` George Greer
2001-10-08 23:30           ` David S. Miller
2001-10-09 10:33           ` Benjamin Herrenschmidt
2001-10-09 11:30             ` Keith Owens
2001-10-09 12:13               ` Benjamin Herrenschmidt
2001-10-09 12:15               ` Alan Cox
2001-10-09  8:51 Etienne Lorrain
2001-10-09 11:30 ` Alan Cox

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