Re: [Qemu-devel] [Qemu-block] [PATCH 09/18] throttle-groups: protect throttled requests with a CoMutex

[Paolo Bonzini]

On 18/05/2017 14:06, Alberto Garcia wrote:
> On Thu 11 May 2017 04:41:59 PM CEST, Paolo Bonzini wrote:
> 
>> --- a/include/sysemu/block-backend.h
>> +++ b/include/sysemu/block-backend.h
>> @@ -72,11 +72,8 @@ typedef struct BlockDevOps {
>>   * fields that must be public. This is in particular for QLIST_ENTRY() and
>>   * friends so that BlockBackends can be kept in lists outside 
>> block-backend.c */
>>  typedef struct BlockBackendPublic {
>> -    /* I/O throttling has its own locking, but also some fields are
>> -     * protected by the AioContext lock.
>> -     */
>> -
>> -    /* Protected by AioContext lock.  */
>> +    /* throttled_reqs_lock protects the CoQueues for throttled requests.  */
>> +    CoMutex      throttled_reqs_lock;
>>      CoQueue      throttled_reqs[2];
>>  
>>      /* Nonzero if the I/O limits are currently being ignored; generally
>>       * it is zero.  */
>>      unsigned int io_limits_disabled;
> 
> Does io_limits_disabled need locking too?

It uses atomic access since patch 3.

Paolo