| Message ID | 20190806150134.104222-5-christian.koenig@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/8] dma-buf: fix busy wait for new shared fences | expand |
Quoting Christian König (2019-08-06 16:01:31) > Other cores don't busy wait any more and we removed the last user of checking > the seqno for changes. Drop updating the number for shared fences altogether. > > Signed-off-by: Christian König <christian.koenig@amd.com> > --- > drivers/dma-buf/reservation.c | 6 ------ > drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 7 +------ > 2 files changed, 1 insertion(+), 12 deletions(-) > > diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c > index c0ba05936ab6..944d962ddddf 100644 > --- a/drivers/dma-buf/reservation.c > +++ b/drivers/dma-buf/reservation.c > @@ -237,9 +237,6 @@ void reservation_object_add_shared_fence(struct reservation_object *obj, > fobj = reservation_object_get_list(obj); > count = fobj->shared_count; > > - preempt_disable(); > - write_seqcount_begin(&obj->seq); > - > for (i = 0; i < count; ++i) { > > old = rcu_dereference_protected(fobj->shared[i], > @@ -257,9 +254,6 @@ void reservation_object_add_shared_fence(struct reservation_object *obj, > RCU_INIT_POINTER(fobj->shared[i], fence); > /* pointer update must be visible before we extend the shared_count */ > smp_store_mb(fobj->shared_count, count); Yup, that's all the mb rules we need to apply for the rcu readers to see a consistent view. Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> -Chris
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c index c0ba05936ab6..944d962ddddf 100644 --- a/drivers/dma-buf/reservation.c +++ b/drivers/dma-buf/reservation.c @@ -237,9 +237,6 @@ void reservation_object_add_shared_fence(struct reservation_object *obj, fobj = reservation_object_get_list(obj); count = fobj->shared_count; - preempt_disable(); - write_seqcount_begin(&obj->seq); - for (i = 0; i < count; ++i) { old = rcu_dereference_protected(fobj->shared[i], @@ -257,9 +254,6 @@ void reservation_object_add_shared_fence(struct reservation_object *obj, RCU_INIT_POINTER(fobj->shared[i], fence); /* pointer update must be visible before we extend the shared_count */ smp_store_mb(fobj->shared_count, count); - - write_seqcount_end(&obj->seq); - preempt_enable(); dma_fence_put(old); } EXPORT_SYMBOL(reservation_object_add_shared_fence); diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index fe062b76ec91..a4640ddc24d1 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -251,12 +251,7 @@ static int amdgpu_amdkfd_remove_eviction_fence(struct amdgpu_bo *bo, new->shared_max = old->shared_max; new->shared_count = k; - /* Install the new fence list, seqcount provides the barriers */ - preempt_disable(); - write_seqcount_begin(&resv->seq); - RCU_INIT_POINTER(resv->fence, new); - write_seqcount_end(&resv->seq); - preempt_enable(); + rcu_assign_pointer(resv->fence, new); /* Drop the references to the removed fences or move them to ef_list */ for (i = j, k = 0; i < old->shared_count; ++i) {
Other cores don't busy wait any more and we removed the last user of checking the seqno for changes. Drop updating the number for shared fences altogether. Signed-off-by: Christian König <christian.koenig@amd.com> --- drivers/dma-buf/reservation.c | 6 ------ drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 7 +------ 2 files changed, 1 insertion(+), 12 deletions(-)