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From: Petr Tesarik <ptesarik@suse.cz>
To: Tony Luck <tony.luck@intel.com>
Cc: "linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Serious problem with ticket spinlocks on ia64
Date: Fri, 3 Sep 2010 16:52:55 +0200	[thread overview]
Message-ID: <201009031652.56476.ptesarik@suse.cz> (raw)
In-Reply-To: <201009031635.25093.ptesarik@suse.cz>

On Friday 03 of September 2010 16:35:23 Petr Tesarik wrote:
> On Friday 03 of September 2010 11:04:37 Petr Tesarik wrote:
> > [...]
> > I'm now trying to modify the lock primitives:
> >
> > 1. replace the fetchadd4.acq with looping over cmpxchg
>
> I did this and I feel dumber than ever.

One more thing - the crash dump I got from that run shows that CPU 2 was just 
going through zap_page_range(), so it probably also did a few global TLB 
flushes. I'm not sure how this should matter, but any idea is good now, I 
think.

Anyway, if a global TLB flush is necessary to trigger the bug, it would also 
explain why we couldn't reproduce it in user-space.

OK, I know I'm just wildly guessing (and don't have any explanation for the 
wrap-around mystery) ... but does anybody have a better idea?

Petr Tesarik

  reply	other threads:[~2010-09-03 14:52 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-27 13:37 Serious problem with ticket spinlocks on ia64 Petr Tesarik
2010-08-27 13:48 ` Hedi Berriche
2010-08-27 14:09   ` Petr Tesarik
2010-08-27 14:31     ` Hedi Berriche
2010-08-27 14:40       ` Petr Tesarik
2010-08-27 14:52         ` Hedi Berriche
2010-08-27 16:37           ` Petr Tesarik
2010-08-27 16:08 ` Luck, Tony
2010-08-27 17:16   ` Petr Tesarik
2010-08-27 18:20     ` Hedi Berriche
2010-08-27 19:40     ` Petr Tesarik
2010-08-27 20:29   ` Luck, Tony
2010-08-27 20:41     ` Petr Tesarik
2010-08-27 21:03     ` Petr Tesarik
2010-08-27 21:11       ` Luck, Tony
2010-08-27 22:13         ` Petr Tesarik
2010-08-27 23:26           ` Luck, Tony
2010-08-27 23:55             ` Luck, Tony
2010-08-28  0:28               ` Hedi Berriche
2010-08-28  5:01                 ` Luck, Tony
2010-08-30 18:17                   ` Luck, Tony
2010-08-30 21:41                     ` Petr Tesarik
2010-08-30 22:43                       ` Tony Luck
2010-08-31 22:17                         ` Tony Luck
2010-09-01 23:09                           ` Tony Luck
2010-09-02  0:26                             ` Hedi Berriche
2010-09-03  0:06                               ` Tony Luck
2010-09-03  9:04                                 ` Petr Tesarik
2010-09-03 14:35                                   ` Petr Tesarik
2010-09-03 14:52                                     ` Petr Tesarik [this message]
2010-09-03 15:50                                       ` Tony Luck
2010-09-06 14:47                                         ` Petr Tesarik
2010-09-07 13:17                                           ` Petr Tesarik
2010-09-07 17:35                                             ` Tony Luck
2010-09-08 15:55                                               ` Tony Luck
2010-09-10  2:55                                     ` Dave Jones

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