Re: [Qemu-devel] [PATCH 0/4] qcow2: Improve cluster refcount update

[Avi Kivity <avi@redhat.com>]

Anthony Liguori wrote:
> Laurent Vivier wrote:
>> Le vendredi 07 novembre 2008 à 07:59 -0600, Anthony Liguori a écrit :
>>   In all cases #1 is totally useless as it is only cosmetic.
>>
>> #2 improves performance without aligned buffers and with "cache" set to
>> default value.
>>   
>
> I'm currently rewriting the block-raw-posix.c O_DIRECT support.  I'll 
> commit your patches once I finish that.
>
> I'm switching everything to use the aio functions, introducing a 
> memory pool so that we can efficiently allocate memory for new 
> requests without having unbounded memory allocation, and switching all 
> the synchronous functions to use the aio functions.

What about locking?  If clusters are already allocated and we don't need 
COW things are simple (and a global lock should suffice, provided it's 
released before the io is actually submitted), but are you planning to 
parallelize the metadata paths as well?

-- 
error compiling committee.c: too many arguments to function