Re: [PATCHv2 1/3] eventfd: allow atomic read and waitqueue remove

Michael S. Tsirkin
2010-01-21T17:32:59Z

On Thu, Jan 21, 2010 at 07:33:02PM +0200, Avi Kivity wrote:
> On 01/21/2010 07:23 PM, Michael S. Tsirkin wrote:
>>
>>> I agree.
>>>
>>> But I think we can solve this in another way in .32: we can clear the
>>> eventfd from irqfd->inject work, which is in process context. The new
>>> stuff is only needed for lockless clearing, no?
>>>
>> No, AFAIK there's no way to clear the counter from kernel without
>> this patch.
>>
>
> Can't you read from the file?

IMO no, the read could block.

> --
> Do not meddle in the internals of kernels, for they are subtle and quick to panic.