From: Richard Weinberger <richard@nod.at>
To: Anton Ivanov <anton.ivanov@kot-begemot.co.uk>,
user-mode-linux-devel@lists.sourceforge.net
Subject: Re: [uml-devel] kernel stalls in balance_dirty_pages_ratelimited()
Date: Thu, 23 Oct 2014 10:36:57 +0200 [thread overview]
Message-ID: <5448BE29.6080103@nod.at> (raw)
In-Reply-To: <5448AF6E.6090201@kot-begemot.co.uk>
Anton,
Am 23.10.2014 um 09:34 schrieb Anton Ivanov:
> Hi Richard,
>
> I have had a question in my mind on this for quite a while around this bug (and a quite a few others).
Fell free to ask, I'll try hand to find time to answer.
> UML by the nature of being UP includes the generic spinlock definition for UP which does very little if any.
Correct. IIRC they are a NOP on UML as it does not support preemption.
> How exactly does this work on a multicore host if you have a different thread hitting the same critical section and that thread is running on a different core? Isn't that
> effectively a form of weird SMP (which in turn requires stricter locking). Am I missing something here?
>>From the host side of view the UML kernel a single process and therefore there is no parallel execution at all.
Does this help?
Thanks,
//richard
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next prev parent reply other threads:[~2014-10-23 8:37 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-13 21:48 [uml-devel] kernel stalls in balance_dirty_pages_ratelimited() Thomas Meyer
2014-10-14 5:38 ` Anton Ivanov
2014-10-14 6:43 ` Anton Ivanov
2014-10-14 7:21 ` Thomas Meyer
2014-10-14 7:31 ` Anton Ivanov
2014-10-19 14:59 ` Thomas Meyer
2014-10-19 16:02 ` Anton Ivanov
2014-10-19 19:35 ` Thomas Meyer
2014-10-20 20:01 ` Thomas Meyer
2014-10-23 7:34 ` Anton Ivanov
2014-10-23 8:36 ` Richard Weinberger [this message]
2014-10-23 8:47 ` Anton Ivanov
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