From: Alex Nixon <alex.nixon@citrix.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] Xen: Fix pte unpin BUG when !CONFIG_SMP
Date: Tue, 09 Sep 2008 23:26:22 +0100 [thread overview]
Message-ID: <48C6F80E.8010509@citrix.com> (raw)
In-Reply-To: <48C6DE6E.1070804@goop.org>
Jeremy Fitzhardinge wrote:
> Alex Nixon wrote:
>
>>
>> Here's the backtrace of the BUG() the patch addresses. Now you've
>> pointed it out - I see the asymmetry - and also suspect some ptes are
>> being left pinned.
>>
>> I'm having trouble finding a cleaner solution which solves this but
>> doesn't incite more BUGs.
>> Perhaps you have an idea?
>>
>
> Right, I see. We shouldn't be pinning ptes on attachment in
> xen_alloc_ptpage() if we're not using split pte locks.
>
> J
>
>
Hmm ok. I'll search further for a solution which fixes things more
officially (and deals with the CONFIG_SMP && (NR_CPUS <
CONFIG_SPLIT_PTLOCK_CPUS) case, which I just realized is also broken,
and isn't fixed by this patch).
In the meantime, at least UP is now usable.
- Alex
next prev parent reply other threads:[~2008-09-09 22:26 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-09 11:25 [PATCH] Xen: Fix pte unpin BUG when !CONFIG_SMP Alex Nixon
2008-09-09 11:27 ` Ingo Molnar
2008-09-09 18:05 ` Jeremy Fitzhardinge
2008-09-09 19:21 ` Alex Nixon
2008-09-09 20:37 ` Jeremy Fitzhardinge
2008-09-09 22:26 ` Alex Nixon [this message]
2008-09-09 22:28 ` Jeremy Fitzhardinge
2008-09-09 22:43 ` [PATCH 1/2] mm: define USE_SPLIT_PTLOCKS rather than repeating expression Jeremy Fitzhardinge
2008-09-10 11:28 ` Hugh Dickins
2008-09-09 22:43 ` [PATCH 2/2] xen: fix pinning when not using split pte locks Jeremy Fitzhardinge
2008-09-09 22:53 ` Andrew Morton
2008-09-09 23:29 ` Jeremy Fitzhardinge
2008-09-10 8:18 ` Ingo Molnar
2008-09-09 23:22 ` Alex Nixon
2008-09-09 23:32 ` Jeremy Fitzhardinge
2008-09-10 8:10 ` Ingo Molnar
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