From: George Dunlap <george.dunlap@citrix.com>
To: Yu Zhang <yu.c.zhang@linux.intel.com>, xen-devel@lists.xen.org
Cc: George Dunlap <george.dunlap@eu.citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
zhiyuan.lv@intel.com, Jan Beulich <jbeulich@suse.com>
Subject: Re: [PATCH RFC] x86/ioreq server: Optimize p2m cleaning up code in p2m_finish_type_change().
Date: Wed, 5 Apr 2017 16:11:18 +0100 [thread overview]
Message-ID: <3d116437-f159-acb1-8be7-11150771efbd@citrix.com> (raw)
In-Reply-To: <1f64b896-8688-4644-6c04-6a3a8263bee6@citrix.com>
On 05/04/17 16:10, George Dunlap wrote:
> On 05/04/17 09:59, Yu Zhang wrote:
>> Previously, p2m_finish_type_change() is triggered to iterate and
>> clean up the p2m table when an ioreq server unmaps from memory type
>> HVMMEM_ioreq_server. And the current iteration number is set to 256
>> And after these iterations, hypercall pre-emption is checked.
>>
>> But it is likely that no p2m change is performed for the just finished
>> iterations, which means p2m_finish_type_change() will return quite
>> soon. So in such scenario, we can allow the p2m iteration to continue,
>> without checking the hypercall pre-emption.
>
> Suppose you have a guest with 128TiB of RAM, and the ioreq_server p2m
> entries are at the very end of RAM. Won't this run for several minutes
> before even allowing preemption?
Sorry, this should be GiB. But I think you get my point. :-)
-George
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next prev parent reply other threads:[~2017-04-05 15:11 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-05 8:59 [PATCH RFC] x86/ioreq server: Optimize p2m cleaning up code in p2m_finish_type_change() Yu Zhang
2017-04-05 15:10 ` George Dunlap
2017-04-05 15:11 ` George Dunlap [this message]
2017-04-05 16:28 ` Yu Zhang
2017-05-09 16:29 ` Jan Beulich
2017-05-10 5:27 ` Yu Zhang
2017-05-09 16:30 ` Jan Beulich
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