Re: [Qemu-devel] [PATCH v7 2/6] Wrapper function to wait on condition for the main loop mutex

[Aravinda Prasad]

On Monday 25 March 2019 11:47 AM, David Gibson wrote:
> On Fri, Mar 22, 2019 at 12:03:49PM +0530, Aravinda Prasad wrote:
>> Introduce a wrapper function to wait on condition for
>> the main loop mutex. This function atomically releases
>> the main loop mutex and causes the calling thread to
>> block on the condition.
>>
>> Signed-off-by: Aravinda Prasad <address@hidden>
> 
> I don't see much value to this.  It's not really more expressive, and
> is barely shorted than just open coding
>       qemu_cond_wait(cond, &qemu_global_mutex)
> wherever you need it.

I have done this way because qemu_global_mutex is static. Do you prefer
removing static instead of this wrapper?

Regards,
Aravinda

> 
> 
>> ---
>>  cpus.c                   |    5 +++++
>>  include/qemu/main-loop.h |    8 ++++++++
>>  2 files changed, 13 insertions(+)
>>
>> diff --git a/cpus.c b/cpus.c
>> index e83f72b..d9379e7 100644
>> --- a/cpus.c
>> +++ b/cpus.c
>> @@ -1858,6 +1858,11 @@ void qemu_mutex_unlock_iothread(void)
>>      qemu_mutex_unlock(&qemu_global_mutex);
>>  }
>>  
>> +void qemu_cond_wait_iothread(QemuCond *cond)
>> +{
>> +    qemu_cond_wait(cond, &qemu_global_mutex);
>> +}
>> +
>>  static bool all_vcpus_paused(void)
>>  {
>>      CPUState *cpu;
>> diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h
>> index f6ba78e..a6d20b0 100644
>> --- a/include/qemu/main-loop.h
>> +++ b/include/qemu/main-loop.h
>> @@ -295,6 +295,14 @@ void qemu_mutex_lock_iothread_impl(const char *file, 
>> int line);
>>   */
>>  void qemu_mutex_unlock_iothread(void);
>>  
>> +/*
>> + * qemu_cond_wait_iothread: Wait on condition for the main loop mutex
>> + *
>> + * This function atomically releases the main loop mutex and causes
>> + * the calling thread to block on the condition.
>> + */
>> +void qemu_cond_wait_iothread(QemuCond *cond);
>> +
>>  /* internal interfaces */
>>  
>>  void qemu_fd_register(int fd);
>>
> 

-- 
Regards,
Aravinda