Re: [PATCH 2/2] drm/amdkfd: Slighly optimize 'init_doorbell_bitmap()'

[Christophe JAILLET]

Le 22/11/2021 à 22:44, Felix Kuehling a écrit :
> Am 2021-11-21 um 12:41 p.m. schrieb Christophe JAILLET:
> > The 'doorbell_bitmap' bitmap has just been allocated. So we can use the
> > non-atomic '__set_bit()' function to save a few cycles as no concurrent
> > access can happen.
> >
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
>
> Thank you for the patches. I think the same sort of change (at least the
> allocation/freeing part) could be applied to the queue_slot_bitmap in
> kfd_process_queue_manager.c. Would you like to submit another revision
> of this patch series that handles that as well?

I'll send a v2 which will fix the missing ',' spotted by the kernel test 
robot and include kfd_process_queue_manager.c.

All my patches are compile tested (otherwise it is said bellow the ---). 
Looks like I missed this one :(.

CJ

> Either way, this series is
>
> Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
>
>
> > ---
> > bitmap_set() could certainly also be use, but range checking would be
> > tricky.
> > ---
> >   drivers/gpu/drm/amd/amdkfd/kfd_process.c | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> > index 172ee8763523..2e9d341062c4 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
> > @@ -1447,9 +1447,9 @@ static int init_doorbell_bitmap(struct qcm_process_device *qpd,
> >   
> >   	for (i = 0; i < KFD_MAX_NUM_OF_QUEUES_PER_PROCESS / 2; i++) {
> >   		if (i >= range_start && i <= range_end) {
> > -			set_bit(i, qpd->doorbell_bitmap);
> > -			set_bit(i + KFD_QUEUE_DOORBELL_MIRROR_OFFSET,
> > -				qpd->doorbell_bitmap);
> > +			__set_bit(i, qpd->doorbell_bitmap);
> > +			__set_bit(i + KFD_QUEUE_DOORBELL_MIRROR_OFFSET,
> > +				  qpd->doorbell_bitmap);
> >   		}
> >   	}
> >