[PATCH v6 6/7] drm/xe: Update PT layer with better error handling
Matthew Auld
matthew.auld at intel.com
Fri Jun 28 15:00:57 UTC 2024
On 26/06/2024 22:15, Matthew Brost wrote:
> Update PT layer so if a memory allocation for a PTE fails the error can
> be propagated to the user without requiring the VM to be killed.
>
> v5:
> - change return value invalidation_fence_init to void (Matthew Auld)
>
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> ---
> drivers/gpu/drm/xe/xe_pt.c | 227 +++++++++++++++++++++++++++----------
> 1 file changed, 164 insertions(+), 63 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
> index f46f46d46819..c043752c0308 100644
> --- a/drivers/gpu/drm/xe/xe_pt.c
> +++ b/drivers/gpu/drm/xe/xe_pt.c
> @@ -846,19 +846,27 @@ xe_vm_populate_pgtable(struct xe_migrate_pt_update *pt_update, struct xe_tile *t
> }
> }
>
> -static void xe_pt_abort_bind(struct xe_vma *vma,
> - struct xe_vm_pgtable_update *entries,
> - u32 num_entries)
> +static void xe_pt_cancel_bind(struct xe_vma *vma,
> + struct xe_vm_pgtable_update *entries,
> + u32 num_entries)
> {
> u32 i, j;
>
> for (i = 0; i < num_entries; i++) {
> - if (!entries[i].pt_entries)
> + struct xe_pt *pt = entries[i].pt;
> +
> + if (!pt)
> continue;
>
> - for (j = 0; j < entries[i].qwords; j++)
> - xe_pt_destroy(entries[i].pt_entries[j].pt, xe_vma_vm(vma)->flags, NULL);
> + if (pt->level) {
> + for (j = 0; j < entries[i].qwords; j++)
> + xe_pt_destroy(entries[i].pt_entries[j].pt,
> + xe_vma_vm(vma)->flags, NULL);
> + }
> +
> kfree(entries[i].pt_entries);
> + entries[i].pt_entries = NULL;
> + entries[i].qwords = 0;
> }
> }
>
> @@ -874,10 +882,61 @@ static void xe_pt_commit_locks_assert(struct xe_vma *vma)
> xe_vm_assert_held(vm);
> }
>
> -static void xe_pt_commit_bind(struct xe_vma *vma,
> - struct xe_vm_pgtable_update *entries,
> - u32 num_entries, bool rebind,
> - struct llist_head *deferred)
> +static void xe_pt_commit(struct xe_vma *vma,
> + struct xe_vm_pgtable_update *entries,
> + u32 num_entries, struct llist_head *deferred)
> +{
> + u32 i, j;
> +
> + xe_pt_commit_locks_assert(vma);
> +
> + for (i = 0; i < num_entries; i++) {
> + struct xe_pt *pt = entries[i].pt;
> +
> + if (!pt->level)
> + continue;
> +
> + 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);
> + }
> + }
> +}
> +
> +static void xe_pt_abort_bind(struct xe_vma *vma,
> + struct xe_vm_pgtable_update *entries,
> + u32 num_entries, bool rebind)
> +{
> + int i, j;
> +
> + xe_pt_commit_locks_assert(vma);
> +
> + for (i = num_entries - 1; i >= 0; --i) {
> + struct xe_pt *pt = entries[i].pt;
> + struct xe_pt_dir *pt_dir;
> +
> + if (!rebind)
> + pt->num_live -= entries[i].qwords;
> +
> + if (!pt->level)
> + continue;
> +
> + pt_dir = as_xe_pt_dir(pt);
> + for (j = 0; j < entries[i].qwords; j++) {
> + u32 j_ = j + entries[i].ofs;
> + struct xe_pt *newpte = xe_pt_entry(pt_dir, j_);
> + struct xe_pt *oldpte = entries[i].pt_entries[j].pt;
> +
> + pt_dir->children[j_] = oldpte ? &oldpte->base : 0;
> + xe_pt_destroy(newpte, xe_vma_vm(vma)->flags, NULL);
> + }
> + }
> +}
> +
> +static void xe_pt_commit_prepare_bind(struct xe_vma *vma,
> + struct xe_vm_pgtable_update *entries,
> + u32 num_entries, bool rebind)
> {
> u32 i, j;
>
> @@ -897,12 +956,13 @@ static void xe_pt_commit_bind(struct xe_vma *vma,
> for (j = 0; j < entries[i].qwords; j++) {
> u32 j_ = j + entries[i].ofs;
> struct xe_pt *newpte = entries[i].pt_entries[j].pt;
> + struct xe_pt *oldpte = NULL;
>
> if (xe_pt_entry(pt_dir, j_))
> - xe_pt_destroy(xe_pt_entry(pt_dir, j_),
> - xe_vma_vm(vma)->flags, deferred);
> + oldpte = xe_pt_entry(pt_dir, j_);
struct xe_pt *oldpte = xe_pt_entry(pt_dir, j_);
?
>
> pt_dir->children[j_] = &newpte->base;
> + entries[i].pt_entries[j].pt = oldpte;
> }
> }
> }
> @@ -926,8 +986,6 @@ xe_pt_prepare_bind(struct xe_tile *tile, struct xe_vma *vma,
> err = xe_pt_stage_bind(tile, vma, entries, num_entries);
> if (!err)
> xe_tile_assert(tile, *num_entries);
> - else /* abort! */
> - xe_pt_abort_bind(vma, entries, *num_entries);
>
> return err;
> }
> @@ -1305,10 +1363,10 @@ static void invalidation_fence_work_func(struct work_struct *w)
> ifence->end, ifence->asid);
> }
>
> -static int invalidation_fence_init(struct xe_gt *gt,
> - struct invalidation_fence *ifence,
> - struct dma_fence *fence,
> - u64 start, u64 end, u32 asid)
> +static void invalidation_fence_init(struct xe_gt *gt,
> + struct invalidation_fence *ifence,
> + struct dma_fence *fence,
> + u64 start, u64 end, u32 asid)
> {
> int ret;
>
> @@ -1340,8 +1398,6 @@ static int invalidation_fence_init(struct xe_gt *gt,
> }
>
> xe_gt_assert(gt, !ret || ret == -ENOENT);
> -
> - return ret && ret != -ENOENT ? ret : 0;
> }
>
> struct xe_pt_stage_unbind_walk {
> @@ -1441,7 +1497,7 @@ xe_pt_stage_unbind_post_descend(struct xe_ptw *parent, pgoff_t offset,
> &end_offset))
> return 0;
>
> - (void)xe_pt_new_shared(&xe_walk->wupd, xe_child, offset, false);
> + (void)xe_pt_new_shared(&xe_walk->wupd, xe_child, offset, true);
Why do we ignore the error here, especially now that alloc_entries=true?
> xe_walk->wupd.updates[level].update->qwords = end_offset - offset;
>
> return 0;
> @@ -1509,32 +1565,57 @@ xe_migrate_clear_pgtable_callback(struct xe_migrate_pt_update *pt_update,
> memset64(ptr, empty, num_qwords);
> }
>
> +static void xe_pt_abort_unbind(struct xe_vma *vma,
> + struct xe_vm_pgtable_update *entries,
> + u32 num_entries)
> +{
> + int j, i;
Nit: i, j inversion, and then below.
> +
> + xe_pt_commit_locks_assert(vma);
> +
> + for (j = num_entries - 1; j >= 0; --j) {
> + struct xe_vm_pgtable_update *entry = &entries[j];
> + struct xe_pt *pt = entry->pt;
> + struct xe_pt_dir *pt_dir = as_xe_pt_dir(pt);
> +
> + pt->num_live += entry->qwords;
> +
> + if (!pt->level)
> + continue;
> +
> + for (i = entry->ofs; i < entry->ofs + entry->qwords; i++)
> + pt_dir->children[i] =
> + entries[j].pt_entries[i - entry->ofs].pt ?
> + &entries[j].pt_entries[i - entry->ofs].pt->base : 0;
s/0/NULL ?
> + }
> +}
> +
> static void
> -xe_pt_commit_unbind(struct xe_vma *vma,
> - struct xe_vm_pgtable_update *entries, u32 num_entries,
> - struct llist_head *deferred)
> +xe_pt_commit_prepare_unbind(struct xe_vma *vma,
> + struct xe_vm_pgtable_update *entries,
> + u32 num_entries)
> {
> - u32 j;
> + int j, i;
And here.
>
> xe_pt_commit_locks_assert(vma);
>
> for (j = 0; j < num_entries; ++j) {
> struct xe_vm_pgtable_update *entry = &entries[j];
> struct xe_pt *pt = entry->pt;
> + struct xe_pt_dir *pt_dir;
>
> pt->num_live -= entry->qwords;
> - if (pt->level) {
> - struct xe_pt_dir *pt_dir = as_xe_pt_dir(pt);
> - u32 i;
> -
> - for (i = entry->ofs; i < entry->ofs + entry->qwords;
> - i++) {
> - if (xe_pt_entry(pt_dir, i))
> - xe_pt_destroy(xe_pt_entry(pt_dir, i),
> - xe_vma_vm(vma)->flags, deferred);
> + if (!pt->level)
> + continue;
>
> - pt_dir->children[i] = NULL;
> - }
> + pt_dir = as_xe_pt_dir(pt);
> + for (i = entry->ofs; i < entry->ofs + entry->qwords; i++) {
> + if (xe_pt_entry(pt_dir, i))
> + entries[j].pt_entries[i - entry->ofs].pt =
> + xe_pt_entry(pt_dir, i);
> + else
> + entries[j].pt_entries[i - entry->ofs].pt = NULL;
entries[j].pt_entries[i - entry->ofs].pt = xe_pt_entry(pt_dir, i)
?
Otherwise,
Reviewed-by: Matthew Auld <matthew.auld at intel.com>
> + pt_dir->children[i] = NULL;
> }
> }
> }
> @@ -1580,7 +1661,6 @@ static int bind_op_prepare(struct xe_vm *vm, struct xe_tile *tile,
> {
> u32 current_op = pt_update_ops->current_op;
> struct xe_vm_pgtable_update_op *pt_op = &pt_update_ops->ops[current_op];
> - struct llist_head *deferred = &pt_update_ops->deferred;
> int err;
>
> xe_bo_assert_held(xe_vma_bo(vma));
> @@ -1628,11 +1708,12 @@ static int bind_op_prepare(struct xe_vm *vm, struct xe_tile *tile,
> /* We bump also if batch_invalidate_tlb is true */
> vm->tlb_flush_seqno++;
>
> - /* FIXME: Don't commit right away */
> vma->tile_staged |= BIT(tile->id);
> pt_op->vma = vma;
> - xe_pt_commit_bind(vma, pt_op->entries, pt_op->num_entries,
> - pt_op->rebind, deferred);
> + xe_pt_commit_prepare_bind(vma, pt_op->entries,
> + pt_op->num_entries, pt_op->rebind);
> + } else {
> + xe_pt_cancel_bind(vma, pt_op->entries, pt_op->num_entries);
> }
>
> return err;
> @@ -1644,7 +1725,6 @@ static int unbind_op_prepare(struct xe_tile *tile,
> {
> u32 current_op = pt_update_ops->current_op;
> struct xe_vm_pgtable_update_op *pt_op = &pt_update_ops->ops[current_op];
> - struct llist_head *deferred = &pt_update_ops->deferred;
> int err;
>
> if (!((vma->tile_present | vma->tile_staged) & BIT(tile->id)))
> @@ -1680,9 +1760,7 @@ static int unbind_op_prepare(struct xe_tile *tile,
> pt_update_ops->needs_userptr_lock |= xe_vma_is_userptr(vma);
> pt_update_ops->needs_invalidation = true;
>
> - /* FIXME: Don't commit right away */
> - xe_pt_commit_unbind(vma, pt_op->entries, pt_op->num_entries,
> - deferred);
> + xe_pt_commit_prepare_unbind(vma, pt_op->entries, pt_op->num_entries);
>
> return 0;
> }
> @@ -1903,7 +1981,7 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops)
> struct invalidation_fence *ifence = NULL;
> struct xe_range_fence *rfence;
> struct xe_vma_op *op;
> - int err = 0;
> + int err = 0, i;
> struct xe_migrate_pt_update update = {
> .ops = pt_update_ops->needs_userptr_lock ?
> &userptr_migrate_ops :
> @@ -1923,8 +2001,10 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops)
>
> if (pt_update_ops->needs_invalidation) {
> ifence = kzalloc(sizeof(*ifence), GFP_KERNEL);
> - if (!ifence)
> - return ERR_PTR(-ENOMEM);
> + if (!ifence) {
> + err = -ENOMEM;
> + goto kill_vm_tile1;
> + }
> }
>
> rfence = kzalloc(sizeof(*rfence), GFP_KERNEL);
> @@ -1939,6 +2019,15 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops)
> goto free_rfence;
> }
>
> + /* Point of no return - VM killed if failure after this */
> + for (i = 0; i < pt_update_ops->current_op; ++i) {
> + struct xe_vm_pgtable_update_op *pt_op = &pt_update_ops->ops[i];
> +
> + xe_pt_commit(pt_op->vma, pt_op->entries,
> + pt_op->num_entries, &pt_update_ops->deferred);
> + pt_op->vma = NULL; /* skip in xe_pt_update_ops_abort */
> + }
> +
> if (xe_range_fence_insert(&vm->rftree[tile->id], rfence,
> &xe_range_fence_kfree_ops,
> pt_update_ops->start,
> @@ -1947,12 +2036,9 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops)
>
> /* tlb invalidation must be done before signaling rebind */
> if (ifence) {
> - err = invalidation_fence_init(tile->primary_gt, ifence, fence,
> - pt_update_ops->start,
> - pt_update_ops->last,
> - vm->usm.asid);
> - if (err)
> - goto put_fence;
> + invalidation_fence_init(tile->primary_gt, ifence, fence,
> + pt_update_ops->start,
> + pt_update_ops->last, vm->usm.asid);
> fence = &ifence->base.base;
> }
>
> @@ -1969,14 +2055,13 @@ xe_pt_update_ops_run(struct xe_tile *tile, struct xe_vma_ops *vops)
>
> return fence;
>
> -put_fence:
> - if (pt_update_ops->needs_userptr_lock)
> - up_read(&vm->userptr.notifier_lock);
> - dma_fence_put(fence);
> free_rfence:
> kfree(rfence);
> free_ifence:
> kfree(ifence);
> +kill_vm_tile1:
> + if (err != -EAGAIN && tile->id)
> + xe_vm_kill(vops->vm, false);
>
> return ERR_PTR(err);
> }
> @@ -1997,12 +2082,10 @@ void xe_pt_update_ops_fini(struct xe_tile *tile, struct xe_vma_ops *vops)
> lockdep_assert_held(&vops->vm->lock);
> xe_vm_assert_held(vops->vm);
>
> - /* FIXME: Not 100% correct */
> - for (i = 0; i < pt_update_ops->num_ops; ++i) {
> + for (i = 0; i < pt_update_ops->current_op; ++i) {
> struct xe_vm_pgtable_update_op *pt_op = &pt_update_ops->ops[i];
>
> - if (pt_op->bind)
> - xe_pt_free_bind(pt_op->entries, pt_op->num_entries);
> + xe_pt_free_bind(pt_op->entries, pt_op->num_entries);
> }
> xe_bo_put_commit(&vops->pt_update_ops[tile->id].deferred);
> }
> @@ -2016,10 +2099,28 @@ void xe_pt_update_ops_fini(struct xe_tile *tile, struct xe_vma_ops *vops)
> */
> void xe_pt_update_ops_abort(struct xe_tile *tile, struct xe_vma_ops *vops)
> {
> + struct xe_vm_pgtable_update_ops *pt_update_ops =
> + &vops->pt_update_ops[tile->id];
> + int i;
> +
> lockdep_assert_held(&vops->vm->lock);
> xe_vm_assert_held(vops->vm);
>
> - /* FIXME: Just kill VM for now + cleanup PTs */
> + for (i = pt_update_ops->num_ops - 1; i >= 0; --i) {
> + struct xe_vm_pgtable_update_op *pt_op =
> + &pt_update_ops->ops[i];
> +
> + if (!pt_op->vma || i >= pt_update_ops->current_op)
> + continue;
> +
> + if (pt_op->bind)
> + xe_pt_abort_bind(pt_op->vma, pt_op->entries,
> + pt_op->num_entries,
> + pt_op->rebind);
> + else
> + xe_pt_abort_unbind(pt_op->vma, pt_op->entries,
> + pt_op->num_entries);
> + }
> +
> xe_bo_put_commit(&vops->pt_update_ops[tile->id].deferred);
> - xe_vm_kill(vops->vm, false);
> }
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