On Tue, Nov 19, 2024 at 04:31:05PM +0100, Thomas Hellström wrote:
> On Tue, 2024-10-15 at 20:25 -0700, Matthew Brost wrote:
> > Add unbind to SVM garbage collector. To facilitate add unbind support
> > function to VM layer which unbinds a SVM range. Also teach PY layer
> > to
> > understand unbinds of SVM ranges.
> >
> > Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/xe/xe_pt.c | 84 ++++++++++++++++++++++++++----
> > --
> > drivers/gpu/drm/xe/xe_svm.c | 9 +++-
> > drivers/gpu/drm/xe/xe_vm.c | 73 +++++++++++++++++++++++++++
> > drivers/gpu/drm/xe/xe_vm.h | 2 +
> > drivers/gpu/drm/xe/xe_vm_types.h | 12 ++++-
> > 5 files changed, 162 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
> > index 024e4eb83408..687abd1a5e74 100644
> > --- a/drivers/gpu/drm/xe/xe_pt.c
> > +++ b/drivers/gpu/drm/xe/xe_pt.c
> > @@ -925,10 +925,16 @@ static void xe_pt_cancel_bind(struct xe_vma
> > *vma,
> > }
> > }
> >
> > +#define INVALID_VMA (struct xe_vma*)(0xdeaddeadull)
>
> Please prefix with XE_ to avoid future name clashes.
>
Good idea.
> > +
> > static void xe_pt_commit_locks_assert(struct xe_vma *vma)
> > {
> > - struct xe_vm *vm = xe_vma_vm(vma);
> > + struct xe_vm *vm;
> >
> > + if (vma == INVALID_VMA)
> > + return;
> > +
> > + vm = xe_vma_vm(vma);
> > lockdep_assert_held(&vm->lock);
> >
> > if (!xe_vma_has_no_bo(vma))
> > @@ -954,7 +960,8 @@ static void xe_pt_commit(struct xe_vma *vma,
> > for (j = 0; j < entries[i].qwords; j++) {
> > struct xe_pt *oldpte =
> > entries[i].pt_entries[j].pt;
> >
> > - xe_pt_destroy(oldpte, xe_vma_vm(vma)->flags,
> > deferred);
> > + xe_pt_destroy(oldpte, (vma == INVALID_VMA) ?
> > 0 :
> > + xe_vma_vm(vma)->flags,
> > deferred);
> > }
> > }
> > }
> > @@ -1387,6 +1394,9 @@ static int xe_pt_svm_pre_commit(struct
> > xe_migrate_pt_update *pt_update)
> > list_for_each_entry(op, &vops->list, link) {
> > struct xe_svm_range *range = op->map_range.range;
> >
> > + if (op->subop == XE_VMA_SUBOP_UNMAP_RANGE)
> > + continue;
> > +
> > xe_assert(vm->xe, xe_vma_is_system_allocator(op-
> > >map_range.vma));
> > xe_assert(vm->xe, op->subop ==
> > XE_VMA_SUBOP_MAP_RANGE);
> >
> > @@ -1585,7 +1595,9 @@ static const struct xe_pt_walk_ops
> > xe_pt_stage_unbind_ops = {
> > * xe_pt_stage_unbind() - Build page-table update structures for an
> > unbind
> > * operation
> > * @tile: The tile we're unbinding for.
> > + * @vm: The vm
> > * @vma: The vma we're unbinding.
> > + * @range: The range we're unbinding.
> > * @entries: Caller-provided storage for the update structures.
> > *
> > * Builds page-table update structures for an unbind operation. The
> > function
> > @@ -1595,9 +1607,14 @@ static const struct xe_pt_walk_ops
> > xe_pt_stage_unbind_ops = {
> > *
> > * Return: The number of entries used.
> > */
> > -static unsigned int xe_pt_stage_unbind(struct xe_tile *tile, struct
> > xe_vma *vma,
> > +static unsigned int xe_pt_stage_unbind(struct xe_tile *tile,
> > + struct xe_vm *vm,
> > + struct xe_vma *vma,
> > + struct xe_svm_range *range,
> > struct xe_vm_pgtable_update
> > *entries)
> > {
> > + u64 start = range ? range->base.va.start :
> > xe_vma_start(vma);
> > + u64 end = range ? range->base.va.end : xe_vma_end(vma);
> > struct xe_pt_stage_unbind_walk xe_walk = {
> > .base = {
> > .ops = &xe_pt_stage_unbind_ops,
> > @@ -1605,14 +1622,14 @@ static unsigned int xe_pt_stage_unbind(struct
> > xe_tile *tile, struct xe_vma *vma,
> > .max_level = XE_PT_HIGHEST_LEVEL,
> > },
> > .tile = tile,
> > - .modified_start = xe_vma_start(vma),
> > - .modified_end = xe_vma_end(vma),
> > + .modified_start = start,
> > + .modified_end = end,
> > .wupd.entries = entries,
> > };
> > - struct xe_pt *pt = xe_vma_vm(vma)->pt_root[tile->id];
> > + struct xe_pt *pt = vm->pt_root[tile->id];
> >
> > - (void)xe_pt_walk_shared(&pt->base, pt->level,
> > xe_vma_start(vma),
> > - xe_vma_end(vma), &xe_walk.base);
> > + (void)xe_pt_walk_shared(&pt->base, pt->level, start, end,
> > + &xe_walk.base);
> >
> > return xe_walk.wupd.num_used_entries;
> > }
> > @@ -1854,13 +1871,6 @@ static int unbind_op_prepare(struct xe_tile
> > *tile,
> > "Preparing unbind, with range [%llx...%llx)\n",
> > xe_vma_start(vma), xe_vma_end(vma) - 1);
> >
> > - /*
> > - * Wait for invalidation to complete. Can corrupt internal
> > page table
> > - * state if an invalidation is running while preparing an
> > unbind.
> > - */
> > - if (xe_vma_is_userptr(vma) &&
> > xe_vm_in_fault_mode(xe_vma_vm(vma)))
> > - mmu_interval_read_begin(&to_userptr_vma(vma)-
> > >userptr.notifier);
> > -
> > pt_op->vma = vma;
> > pt_op->bind = false;
> > pt_op->rebind = false;
> > @@ -1869,7 +1879,8 @@ static int unbind_op_prepare(struct xe_tile
> > *tile,
> > if (err)
> > return err;
> >
> > - pt_op->num_entries = xe_pt_stage_unbind(tile, vma, pt_op-
> > >entries);
> > + pt_op->num_entries = xe_pt_stage_unbind(tile,
> > xe_vma_vm(vma),
> > + vma, NULL, pt_op-
> > >entries);
> >
> > xe_vm_dbg_print_entries(tile_to_xe(tile), pt_op->entries,
> > pt_op->num_entries, false);
> > @@ -1884,6 +1895,42 @@ static int unbind_op_prepare(struct xe_tile
> > *tile,
> > return 0;
> > }
> >
> > +static int unbind_range_prepare(struct xe_vm *vm,
> > + struct xe_tile *tile,
> > + struct xe_vm_pgtable_update_ops
> > *pt_update_ops,
> > + struct xe_svm_range *range)
> > +{
> > + u32 current_op = pt_update_ops->current_op;
> > + struct xe_vm_pgtable_update_op *pt_op = &pt_update_ops-
> > >ops[current_op];
> > +
> > + if (!(range->tile_present & BIT(tile->id)))
> > + return 0;
> > +
> > + vm_dbg(&vm->xe->drm,
> > + "Preparing unbind, with range [%llx...%llx)\n",
> > + range->base.va.start, range->base.va.end - 1);
> > +
> > + pt_op->vma = INVALID_VMA;
> > + pt_op->bind = false;
> > + pt_op->rebind = false;
> > +
> > + pt_op->num_entries = xe_pt_stage_unbind(tile, vm, NULL,
> > range,
> > + pt_op->entries);
> > +
> > + xe_vm_dbg_print_entries(tile_to_xe(tile), pt_op->entries,
> > + pt_op->num_entries, false);
> > + xe_pt_update_ops_rfence_interval(pt_update_ops, range-
> > >base.va.start,
> > + range->base.va.end);
> > + ++pt_update_ops->current_op;
> > + pt_update_ops->needs_svm_lock = true;
> > + pt_update_ops->needs_invalidation = true;
> > +
> > + xe_pt_commit_prepare_unbind(INVALID_VMA, pt_op->entries,
> > + pt_op->num_entries);
> > +
> > + return 0;
> > +}
> > +
> > static int op_prepare(struct xe_vm *vm,
> > struct xe_tile *tile,
> > struct xe_vm_pgtable_update_ops
> > *pt_update_ops,
> > @@ -1951,6 +1998,9 @@ static int op_prepare(struct xe_vm *vm,
> > err = bind_range_prepare(vm, tile,
> > pt_update_ops,
> > op->map_range.vma,
> > op-
> > >map_range.range);
> > + } else if (op->subop == XE_VMA_SUBOP_UNMAP_RANGE) {
> > + err = unbind_range_prepare(vm, tile,
> > pt_update_ops,
> > + op-
> > >unmap_range.range);
> > }
> > break;
> > default:
> > @@ -2139,6 +2189,8 @@ static void op_commit(struct xe_vm *vm,
> > if (op->subop == XE_VMA_SUBOP_MAP_RANGE) {
> > op->map_range.range->tile_present |=
> > BIT(tile->id);
> > op->map_range.range->tile_invalidated &=
> > ~BIT(tile->id);
> > + } else if (op->subop == XE_VMA_SUBOP_UNMAP_RANGE) {
> > + op->unmap_range.range->tile_present &=
> > ~BIT(tile->id);
> > }
> > break;
> > }
>
> I think this further stresses the need to provide a pt code interface
> that is oblivious of vmas, userptr and ranges so that we can get rid of
> all special-casing, but for now code looks good as is IMO.
>
I agree eventually it would be nice drop vmas / userptr / ranges from
the bind code. I believe I even opened a Jira for this task. The main
issue I see is tile_present, tile_invalidated needs to be moved to the
PT state which is a fairly large refactor. We also short circuit in
bunch of places based on this state which would turn into a page table
walk which also needs to be considered too.
As long as you ok with this for now, I agree let's scope / do in a
follow up.
>
> > diff --git a/drivers/gpu/drm/xe/xe_svm.c
> > b/drivers/gpu/drm/xe/xe_svm.c
> > index 9c2f44cba166..0762126f65e0 100644
> > --- a/drivers/gpu/drm/xe/xe_svm.c
> > +++ b/drivers/gpu/drm/xe/xe_svm.c
> > @@ -208,7 +208,14 @@ static void xe_svm_invalidate(struct drm_gpusvm
> > *gpusvm,
> > static int __xe_svm_garbage_collector(struct xe_vm *vm,
> > struct xe_svm_range *range)
> > {
> > - /* TODO: Do unbind */
> > + struct dma_fence *fence;
> > +
> > + xe_vm_lock(vm, false);
> > + fence = xe_vm_range_unbind(vm, range);
> > + xe_vm_unlock(vm);
> > + if (IS_ERR(fence))
> > + return PTR_ERR(fence);
> > + dma_fence_put(fence);
> >
> > drm_gpusvm_range_remove(&vm->svm.gpusvm, &range->base);
> >
> > diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> > index 399cbbdbddd5..76a20e96084e 100644
> > --- a/drivers/gpu/drm/xe/xe_vm.c
> > +++ b/drivers/gpu/drm/xe/xe_vm.c
> > @@ -972,6 +972,79 @@ struct dma_fence *xe_vm_range_rebind(struct
> > xe_vm *vm,
> > return fence;
> > }
> >
> > +static void xe_vm_populate_range_unbind(struct xe_vma_op *op,
> > + struct xe_svm_range *range)
> > +{
> > + INIT_LIST_HEAD(&op->link);
> > + op->tile_mask = range->tile_present;
> > + op->base.op = DRM_GPUVA_OP_USER;
> > + op->subop = XE_VMA_SUBOP_UNMAP_RANGE;
> > + op->unmap_range.range = range;
> > +}
> > +
> > +static int
> > +xe_vm_ops_add_range_unbind(struct xe_vma_ops *vops,
> > + struct xe_svm_range *range)
> > +{
> > + struct xe_vma_op *op;
> > +
> > + op = kzalloc(sizeof(*op), GFP_KERNEL);
> > + if (!op)
> > + return -ENOMEM;
> > +
> > + xe_vm_populate_range_unbind(op, range);
> > + list_add_tail(&op->link, &vops->list);
> > + xe_vma_ops_incr_pt_update_ops(vops, range->tile_present);
> > +
> > + return 0;
> > +}
> > +
> > +struct dma_fence *xe_vm_range_unbind(struct xe_vm *vm,
> > + struct xe_svm_range *range)
>
> Kerneldoc.
>
Yep.
Matt
>
> > +{
> > + struct dma_fence *fence = NULL;
> > + struct xe_vma_ops vops;
> > + struct xe_vma_op *op, *next_op;
> > + struct xe_tile *tile;
> > + u8 id;
> > + int err;
> > +
> > + lockdep_assert_held(&vm->lock);
> > + xe_vm_assert_held(vm);
> > + xe_assert(vm->xe, xe_vm_in_fault_mode(vm));
> > +
> > + if (!range->tile_present)
> > + return dma_fence_get_stub();
> > +
> > + xe_vma_ops_init(&vops, vm, NULL, NULL, 0);
> > + for_each_tile(tile, vm->xe, id) {
> > + vops.pt_update_ops[id].wait_vm_bookkeep = true;
> > + vops.pt_update_ops[tile->id].q =
> > + xe_tile_migrate_exec_queue(tile);
> > + }
> > +
> > + err = xe_vm_ops_add_range_unbind(&vops, range);
> > + if (err)
> > + return ERR_PTR(err);
> > +
> > + err = xe_vma_ops_alloc(&vops, false);
> > + if (err) {
> > + fence = ERR_PTR(err);
> > + goto free_ops;
> > + }
> > +
> > + fence = ops_execute(vm, &vops);
> > +
> > +free_ops:
> > + list_for_each_entry_safe(op, next_op, &vops.list, link) {
> > + list_del(&op->link);
> > + kfree(op);
> > + }
> > + xe_vma_ops_fini(&vops);
> > +
> > + return fence;
> > +}
> > +
> > static void xe_vma_free(struct xe_vma *vma)
> > {
> > if (xe_vma_is_userptr(vma))
> > diff --git a/drivers/gpu/drm/xe/xe_vm.h b/drivers/gpu/drm/xe/xe_vm.h
> > index 8bd921b33090..d577ca9e3d65 100644
> > --- a/drivers/gpu/drm/xe/xe_vm.h
> > +++ b/drivers/gpu/drm/xe/xe_vm.h
> > @@ -222,6 +222,8 @@ struct dma_fence *xe_vm_range_rebind(struct xe_vm
> > *vm,
> > struct xe_vma *vma,
> > struct xe_svm_range *range,
> > u8 tile_mask);
> > +struct dma_fence *xe_vm_range_unbind(struct xe_vm *vm,
> > + struct xe_svm_range *range);
> >
> > int xe_vm_invalidate_vma(struct xe_vma *vma);
> >
> > diff --git a/drivers/gpu/drm/xe/xe_vm_types.h
> > b/drivers/gpu/drm/xe/xe_vm_types.h
> > index 2eae3575c409..d38cf7558f62 100644
> > --- a/drivers/gpu/drm/xe/xe_vm_types.h
> > +++ b/drivers/gpu/drm/xe/xe_vm_types.h
> > @@ -348,6 +348,12 @@ struct xe_vma_op_map_range {
> > struct xe_svm_range *range;
> > };
> >
> > +/** struct xe_vma_op_unmap_range - VMA unmap range operation */
> > +struct xe_vma_op_unmap_range {
> > + /** @range: SVM range to unmap */
> > + struct xe_svm_range *range;
> > +};
> > +
> > /** enum xe_vma_op_flags - flags for VMA operation */
> > enum xe_vma_op_flags {
> > /** @XE_VMA_OP_COMMITTED: VMA operation committed */
> > @@ -362,6 +368,8 @@ enum xe_vma_op_flags {
> > enum xe_vma_subop {
> > /** @XE_VMA_SUBOP_MAP_RANGE: Map range */
> > XE_VMA_SUBOP_MAP_RANGE,
> > + /** @XE_VMA_SUBOP_UNMAP_RANGE: Unmap range */
> > + XE_VMA_SUBOP_UNMAP_RANGE,
> > };
> >
> > /** struct xe_vma_op - VMA operation */
> > @@ -384,8 +392,10 @@ struct xe_vma_op {
> > struct xe_vma_op_remap remap;
> > /** @prefetch: VMA prefetch operation specific data
> > */
> > struct xe_vma_op_prefetch prefetch;
> > - /** @map: VMA map range operation specific data */
> > + /** @map_range: VMA map range operation specific
> > data */
> > struct xe_vma_op_map_range map_range;
> > + /** @unmap_range: VMA unmap range operation specific
> > data */
> > + struct xe_vma_op_map_range unmap_range;
> > };
> > };
> >
>
> Thanks,
> Thomas
>
