Re: [PATCH 1/2] KVM: Convert kvm_lock to raw_spinlock

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2011-02-09 10:25, Avi Kivity wrote:
> On 02/09/2011 11:24 AM, Avi Kivity wrote:
>> On 02/08/2011 01:55 PM, Jan Kiszka wrote:
>>> Code under this lock requires non-preemptibility. Ensure this also over
>>> -rt by converting it to raw spinlock.
>>>
>>
>> Please add a code comment documenting what data under this lock 
>> requires it to be a raw spinlock.
>>
> 
> Or better, put it in Documentation/kvm/locking.txt, which we'll try to 
> grow to cover all locks.
> 

Something like

[Documentation/kvm/locking.txt]
KVM Lock Overview
-----------------

1. Spin locks

1.1 tsc_write_lock

Type:		raw
Arch:		x86
Protects:	kvm_arch::{last_tsc_write,last_tsc_nsec,last_tsc_offset}
		tsc offset in vmcb
Comment:	'raw' because updating the tsc offsets must not be preempted
...

?

Jan

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