Re: [Qemu-devel] [PATCH v3 08/10] Use QemuEvent for POSIX AIO

[Stefan Hajnoczi]

On Tue, Apr 10, 2012 at 4:45 PM, Jan Kiszka <address@hidden> wrote:
> On 2012-04-10 17:31, Stefan Hajnoczi wrote:
>> On Thu, Apr 5, 2012 at 11:59 AM, Jan Kiszka <address@hidden> wrote:
>>> Use QemuEvent for signaling POSIX AIO completions. If native eventfd
>>> support is available, this avoids multiple read accesses to drain
>>> multiple pending signals.
>>>
>>> Signed-off-by: Jan Kiszka <address@hidden>
>>> ---
>>>  posix-aio-compat.c |   62 
>>> ++++++----------------------------------------------
>>>  1 files changed, 7 insertions(+), 55 deletions(-)
>>
>> We can save a file descriptor by scheduling a BH (if not already
>> scheduled) and calling qemu_notify_event() instead of using a
>> dedicated QemuEvent.  I may have missed something, just got back from
>> vacation :).
>
> Likely feasible, but not that straightforward: We would still have to
> provide qemu_aio_{wait,flush,...} services for posix-aio-compat, I presume.

True, it's much easier to use a dedicated fd.

Stefan