Re: [Qemu-devel] [PATCH 1/5] atomic: introduce smp_mb_acquire and smp_mb_release

[Paolo Bonzini]

On 10/10/2016 17:29, Eric Blake wrote:
> On 10/10/2016 08:59 AM, Paolo Bonzini wrote:
>> Signed-off-by: Paolo Bonzini <address@hidden>
>> ---
>>  docs/atomics.txt      | 79 
>> ++++++++++++++++++++++++++++++---------------------
>>  include/qemu/atomic.h | 50 +++++++++++++++++++-------------
>>  2 files changed, 77 insertions(+), 52 deletions(-)
>>
> 
>>  
>> +- smp_mb_acquire() guarantees that all the LOAD operations specified before
>> +  the barrier will appear to happen before all the LOAD or STORE operations
>> +  specified after the barrier with respect to the other components of
>> +  the system.
>> +
>> +- smp_mb_release() guarantees that all the STORE operations specified 
>> *after*
>> +  the barrier will appear to happen before all the LOAD or STORE operations
> 
> Sounds impossible.  Should this be 'will appear to happen after all'?

Yes, of course.  Damn copy and paste...

Paolo

>> +  specified *before* the barrier with respect to the other components of
>> +  the system.
>> +
>>  - smp_mb() guarantees that all the LOAD and STORE operations specified
>>    before the barrier will appear to happen before all the LOAD and
>>    STORE operations specified after the barrier with respect to the other
>> @@ -149,8 +160,9 @@ They come in four kinds:
> 
>