Re: [Qemu-devel] [PATCH 11/15] lock: introduce global lock for device tree

[liu ping fan]

On Wed, Aug 8, 2012 at 5:41 PM, Paolo Bonzini <address@hidden> wrote:
> Il 08/08/2012 08:25, Liu Ping Fan ha scritto:
>> From: Liu Ping Fan <address@hidden>
>>
>> Signed-off-by: Liu Ping Fan <address@hidden>
>> ---
>>  cpus.c      |   12 ++++++++++++
>>  main-loop.h |    3 +++
>>  2 files changed, 15 insertions(+), 0 deletions(-)
>>
>> diff --git a/cpus.c b/cpus.c
>> index b182b3d..a734b36 100644
>> --- a/cpus.c
>> +++ b/cpus.c
>> @@ -611,6 +611,7 @@ static void qemu_tcg_init_cpu_signals(void)
>>  }
>>  #endif /* _WIN32 */
>>
>> +QemuMutex qemu_device_tree_mutex;
>>  QemuMutex qemu_global_mutex;
>>  static QemuCond qemu_io_proceeded_cond;
>>  static bool iothread_requesting_mutex;
>> @@ -634,6 +635,7 @@ void qemu_init_cpu_loop(void)
>>      qemu_cond_init(&qemu_work_cond);
>>      qemu_cond_init(&qemu_io_proceeded_cond);
>>      qemu_mutex_init(&qemu_global_mutex);
>> +    qemu_mutex_init(&qemu_device_tree_mutex);
>>
>>      qemu_thread_get_self(&io_thread);
>>  }
>> @@ -911,6 +913,16 @@ void qemu_mutex_unlock_iothread(void)
>>      qemu_mutex_unlock(&qemu_global_mutex);
>>  }
>>
>> +void qemu_lock_devtree(void)
>> +{
>> +    qemu_mutex_lock(&qemu_device_tree_mutex);
>> +}
>> +
>> +void qemu_unlock_devtree(void)
>> +{
>> +    qemu_mutex_unlock(&qemu_device_tree_mutex);
>> +}
>
> We don't need the wrappers.  They are there for the big lock just
> because TCG needs extra work for iothread_requesting_mutex.
>
Sorry, could you give more detail about TCG, what is extra work.

Thanks,
pingfan

> Paolo
>
>>  static int all_vcpus_paused(void)
>>  {
>>      CPUArchState *penv = first_cpu;
>> diff --git a/main-loop.h b/main-loop.h
>> index dce1cd9..17e959a 100644
>> --- a/main-loop.h
>> +++ b/main-loop.h
>> @@ -353,6 +353,9 @@ void qemu_mutex_lock_iothread(void);
>>   */
>>  void qemu_mutex_unlock_iothread(void);
>>
>> +void qemu_lock_devtree(void);
>> +void qemu_unlock_devtree(void);
>> +
>>  /* internal interfaces */
>>
>>  void qemu_fd_register(int fd);
>>
>
>