On 02/07/2011 05:58 PM, Jan Kiszka wrote:
On 2011-02-07 16:52, Avi Kivity wrote:
> On 02/07/2011 05:38 PM, Jan Kiszka wrote:
>>>
>>> I don't know as it is allowed to sleep, it doesn't call any sleeping
>>> functions to my knowledge. What worries me in the RT case is that the
>>> spinlock acquired for hardware_enable might be preempted and run on
>>> another CPU, which obviously isn't what you want.
>>
>> I see now, there are calls to raw_smp_processor_id.
>>
>> I think it's best to make this a raw lock. At this chance, some
>> read-only users of vm_list should be rcu'ified. Will have a look.
>
> vm_list is rarely used, for either read or write. I don't see the need
> to rcu it.
Avoid that code under this lock expands the preempt-disabled period,
specifically under -rt, and specifically as the number of objects over
which we loop is user-defined.
Good point; even under non-rt.
(well, actually, cpufreq_notifier and kvm_arch_hardware_enable are
already non preemptible, and the stats code should just go away?)
--
error compiling committee.c: too many arguments to function
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