Re: [PATCH v8 10/10] MCS Lock: Make mcs_spinlock.h includable in other files

[Waiman Long <waiman.long@hp.com>]

On 10/24/2013 04:58 PM, Tim Chen wrote:
>
> Do we want to inline the unlock?  Will that prevent proper profile
> accounting of unlock overhead?
>
> Can we keep the mcs_spin_unlock and mcs_spin_lock in the same
> kernel/mcs_spinlock.c file? That makes it easier to read and
> maintain the code.

The unlock code is fast. The lock code, however, can run for a long 
time. It will greatly increase the reported time spent in the calling 
function if it is inlined. The same is true for spinlock. The 
_raw_spin_lock() is a real function while _raw_spin_unlock() is inlined 
in most cases.

Yes, I can bring the lock function back to the mcs_spinlock.h file with 
name like _raw_mcs_spin_lock() and the mcs_spin_lock() in mcs_spinlock.c 
will include the raw function. In that way, the mcs_spin_lock() will 
still be a separate function while both the lock and unlock code will be 
together.

> Can you check if you have applied all the previous MCS patches?
> The last two for barrier corrections and optimizations seem
> to be missing.
>
> MCS Lock: optimizations and extra comments
> https://lkml.org/lkml/2013/10/2/644
> MCS Lock: Barrier corrections
> https://lkml.org/lkml/2013/10/2/650
>
> Thanks.
>
> Tim
>

Apparently, I does have all the MCS patch  in my git tree. I will 
regenerate a new one with the right diff. Thank for the review.

-Longman