On 2019-10-28 4:10 p.m., Jason Gunthorpe wrote:
> From: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
>
> Remove the interval tree in the driver and rely on the tree maintained by
> the mmu_notifier for delivering mmu_notifier invalidation callbacks.
>
> For some reason amdgpu has a very complicated arrangement where it tries
> to prevent duplicate entries in the interval_tree, this is not necessary,
> each amdgpu_bo can be its own stand alone entry. interval_tree already
> allows duplicates and overlaps in the tree.
>
> Also, there is no need to remove entries upon a release callback, the
> mmu_range API safely allows objects to remain registered beyond the
> lifetime of the mm. The driver only has to stop touching the pages during
> release.
>
> Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> Cc: Christian König <christian.koenig@xxxxxxx>
> Cc: David (ChunMing) Zhou <David1.Zhou@xxxxxxx>
> Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu.h | 2 +
> .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 5 +-
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 1 +
> drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c | 341 ++++--------------
> drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h | 4 -
> drivers/gpu/drm/amd/amdgpu/amdgpu_object.h | 13 +-
> 6 files changed, 84 insertions(+), 282 deletions(-)
[snip]
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
> index 31d4deb5d29484..4ffd7b90f4d907 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
[snip]
> @@ -50,66 +50,6 @@
> #include "amdgpu.h"
> #include "amdgpu_amdkfd.h"
>
> -/**
> - * struct amdgpu_mn_node
> - *
> - * @it: interval node defining start-last of the affected address range
> - * @bos: list of all BOs in the affected address range
> - *
> - * Manages all BOs which are affected of a certain range of address space.
> - */
> -struct amdgpu_mn_node {
> - struct interval_tree_node it;
> - struct list_head bos;
> -};
> -
> -/**
> - * amdgpu_mn_destroy - destroy the HMM mirror
> - *
> - * @work: previously sheduled work item
> - *
> - * Lazy destroys the notifier from a work item
> - */
> -static void amdgpu_mn_destroy(struct work_struct *work)
> -{
> - struct amdgpu_mn *amn = container_of(work, struct amdgpu_mn, work);
> - struct amdgpu_device *adev = amn->adev;
> - struct amdgpu_mn_node *node, *next_node;
> - struct amdgpu_bo *bo, *next_bo;
> -
> - mutex_lock(&adev->mn_lock);
> - down_write(&amn->lock);
> - hash_del(&amn->node);
> - rbtree_postorder_for_each_entry_safe(node, next_node,
> - &amn->objects.rb_root, it.rb) {
> - list_for_each_entry_safe(bo, next_bo, &node->bos, mn_list) {
> - bo->mn = NULL;
> - list_del_init(&bo->mn_list);
> - }
> - kfree(node);
> - }
> - up_write(&amn->lock);
> - mutex_unlock(&adev->mn_lock);
> -
> - hmm_mirror_unregister(&amn->mirror);
> - kfree(amn);
> -}
> -
> -/**
> - * amdgpu_hmm_mirror_release - callback to notify about mm destruction
> - *
> - * @mirror: the HMM mirror (mm) this callback is about
> - *
> - * Shedule a work item to lazy destroy HMM mirror.
> - */
> -static void amdgpu_hmm_mirror_release(struct hmm_mirror *mirror)
> -{
> - struct amdgpu_mn *amn = container_of(mirror, struct amdgpu_mn, mirror);
> -
> - INIT_WORK(&amn->work, amdgpu_mn_destroy);
> - schedule_work(&amn->work);
> -}
> -
> /**
> * amdgpu_mn_lock - take the write side lock for this notifier
> *
> @@ -133,157 +73,86 @@ void amdgpu_mn_unlock(struct amdgpu_mn *mn)
> }
>
> /**
> - * amdgpu_mn_read_lock - take the read side lock for this notifier
> - *
> - * @amn: our notifier
> - */
> -static int amdgpu_mn_read_lock(struct amdgpu_mn *amn, bool blockable)
> -{
> - if (blockable)
> - down_read(&amn->lock);
> - else if (!down_read_trylock(&amn->lock))
> - return -EAGAIN;
> -
> - return 0;
> -}
> -
> -/**
> - * amdgpu_mn_read_unlock - drop the read side lock for this notifier
> - *
> - * @amn: our notifier
> - */
> -static void amdgpu_mn_read_unlock(struct amdgpu_mn *amn)
> -{
> - up_read(&amn->lock);
> -}
> -
> -/**
> - * amdgpu_mn_invalidate_node - unmap all BOs of a node
> + * amdgpu_mn_invalidate_gfx - callback to notify about mm change
> *
> - * @node: the node with the BOs to unmap
> - * @start: start of address range affected
> - * @end: end of address range affected
> + * @mrn: the range (mm) is about to update
> + * @range: details on the invalidation
> *
> * Block for operations on BOs to finish and mark pages as accessed and
> * potentially dirty.
> */
> -static void amdgpu_mn_invalidate_node(struct amdgpu_mn_node *node,
> - unsigned long start,
> - unsigned long end)
> +static bool amdgpu_mn_invalidate_gfx(struct mmu_range_notifier *mrn,
> + const struct mmu_notifier_range *range)
> {
> - struct amdgpu_bo *bo;
> + struct amdgpu_bo *bo = container_of(mrn, struct amdgpu_bo, notifier);
> + struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> long r;
>
> - list_for_each_entry(bo, &node->bos, mn_list) {
> -
> - if (!amdgpu_ttm_tt_affect_userptr(bo->tbo.ttm, start, end))
> - continue;
> -
> - r = dma_resv_wait_timeout_rcu(bo->tbo.base.resv,
> - true, false, MAX_SCHEDULE_TIMEOUT);
> - if (r <= 0)
> - DRM_ERROR("(%ld) failed to wait for user bo\n", r);
> - }
> + /* FIXME: Is this necessary? */
> + if (!amdgpu_ttm_tt_affect_userptr(bo->tbo.ttm, range->start,
> + range->end))
> + return true;
> +
> + if (!mmu_notifier_range_blockable(range))
> + return false;
> +
> + mutex_lock(&adev->notifier_lock);
> + r = dma_resv_wait_timeout_rcu(bo->tbo.base.resv, true, false,
> + MAX_SCHEDULE_TIMEOUT);
> + mutex_unlock(&adev->notifier_lock);
> + if (r <= 0)
> + DRM_ERROR("(%ld) failed to wait for user bo\n", r);
> + return true;
> }
>
> +static const struct mmu_range_notifier_ops amdgpu_mn_gfx_ops = {
> + .invalidate = amdgpu_mn_invalidate_gfx,
> +};
> +
> /**
> - * amdgpu_mn_sync_pagetables_gfx - callback to notify about mm change
> + * amdgpu_mn_invalidate_hsa - callback to notify about mm change
> *
> - * @mirror: the hmm_mirror (mm) is about to update
> - * @update: the update start, end address
> + * @mrn: the range (mm) is about to update
> + * @range: details on the invalidation
> *
> - * Block for operations on BOs to finish and mark pages as accessed and
> - * potentially dirty.
> + * We temporarily evict the BO attached to this range. This necessitates
> + * evicting all user-mode queues of the process.
> */
> -static int
> -amdgpu_mn_sync_pagetables_gfx(struct hmm_mirror *mirror,
> - const struct mmu_notifier_range *update)
> +static bool amdgpu_mn_invalidate_hsa(struct mmu_range_notifier *mrn,
> + const struct mmu_notifier_range *range)
> {
> - struct amdgpu_mn *amn = container_of(mirror, struct amdgpu_mn, mirror);
> - unsigned long start = update->start;
> - unsigned long end = update->end;
> - bool blockable = mmu_notifier_range_blockable(update);
> - struct interval_tree_node *it;
> -
> - /* notification is exclusive, but interval is inclusive */
> - end -= 1;
> -
> - /* TODO we should be able to split locking for interval tree and
> - * amdgpu_mn_invalidate_node
> - */
> - if (amdgpu_mn_read_lock(amn, blockable))
> - return -EAGAIN;
> -
> - it = interval_tree_iter_first(&amn->objects, start, end);
> - while (it) {
> - struct amdgpu_mn_node *node;
> -
> - if (!blockable) {
> - amdgpu_mn_read_unlock(amn);
> - return -EAGAIN;
> - }
> + struct amdgpu_bo *bo = container_of(mrn, struct amdgpu_bo, notifier);
> + struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>
> - node = container_of(it, struct amdgpu_mn_node, it);
> - it = interval_tree_iter_next(it, start, end);
> + /* FIXME: Is this necessary? */
> + if (!amdgpu_ttm_tt_affect_userptr(bo->tbo.ttm, range->start,
> + range->end))
> + return true;
>
> - amdgpu_mn_invalidate_node(node, start, end);
> - }
> + if (!mmu_notifier_range_blockable(range))
> + return false;
>
> - amdgpu_mn_read_unlock(amn);
> + mutex_lock(&adev->notifier_lock);
> + amdgpu_amdkfd_evict_userptr(bo->kfd_bo, bo->notifier.mm);
> + mutex_unlock(&adev->notifier_lock);
>
> - return 0;
> + return true;
> }
>
> -/**
> - * amdgpu_mn_sync_pagetables_hsa - callback to notify about mm change
> - *
> - * @mirror: the hmm_mirror (mm) is about to update
> - * @update: the update start, end address
> - *
> - * We temporarily evict all BOs between start and end. This
> - * necessitates evicting all user-mode queues of the process. The BOs
> - * are restorted in amdgpu_mn_invalidate_range_end_hsa.
> - */
> -static int
> -amdgpu_mn_sync_pagetables_hsa(struct hmm_mirror *mirror,
> - const struct mmu_notifier_range *update)
> +static const struct mmu_range_notifier_ops amdgpu_mn_hsa_ops = {
> + .invalidate = amdgpu_mn_invalidate_hsa,
> +};
> +
> +static int amdgpu_mn_sync_pagetables(struct hmm_mirror *mirror,
> + const struct mmu_notifier_range *update)
> {
> struct amdgpu_mn *amn = container_of(mirror, struct amdgpu_mn, mirror);
> - unsigned long start = update->start;
> - unsigned long end = update->end;
> - bool blockable = mmu_notifier_range_blockable(update);
> - struct interval_tree_node *it;
>
> - /* notification is exclusive, but interval is inclusive */
> - end -= 1;
> -
> - if (amdgpu_mn_read_lock(amn, blockable))
> - return -EAGAIN;
> -
> - it = interval_tree_iter_first(&amn->objects, start, end);
> - while (it) {
> - struct amdgpu_mn_node *node;
> - struct amdgpu_bo *bo;
> -
> - if (!blockable) {
> - amdgpu_mn_read_unlock(amn);
> - return -EAGAIN;
> - }
> -
> - node = container_of(it, struct amdgpu_mn_node, it);
> - it = interval_tree_iter_next(it, start, end);
> -
> - list_for_each_entry(bo, &node->bos, mn_list) {
> - struct kgd_mem *mem = bo->kfd_bo;
> -
> - if (amdgpu_ttm_tt_affect_userptr(bo->tbo.ttm,
> - start, end))
> - amdgpu_amdkfd_evict_userptr(mem, amn->mm);
> - }
> - }
> -
> - amdgpu_mn_read_unlock(amn);
> + if (!mmu_notifier_range_blockable(update))
> + return false;
This should return -EAGAIN. Not sure it matters much, because this whole
function disappears in the next commit in the series. It seems to be
only vestigial at this point.
Regards,
Felix
>
> + down_read(&amn->lock);
> + up_read(&amn->lock);
> return 0;
> }
>
> @@ -295,12 +164,10 @@ amdgpu_mn_sync_pagetables_hsa(struct hmm_mirror *mirror,
>
> static struct hmm_mirror_ops amdgpu_hmm_mirror_ops[] = {
> [AMDGPU_MN_TYPE_GFX] = {
> - .sync_cpu_device_pagetables = amdgpu_mn_sync_pagetables_gfx,
> - .release = amdgpu_hmm_mirror_release
> + .sync_cpu_device_pagetables = amdgpu_mn_sync_pagetables,
> },
> [AMDGPU_MN_TYPE_HSA] = {
> - .sync_cpu_device_pagetables = amdgpu_mn_sync_pagetables_hsa,
> - .release = amdgpu_hmm_mirror_release
> + .sync_cpu_device_pagetables = amdgpu_mn_sync_pagetables,
> },
> };
>
> @@ -327,7 +194,8 @@ struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
> }
>
> hash_for_each_possible(adev->mn_hash, amn, node, key)
> - if (AMDGPU_MN_KEY(amn->mm, amn->type) == key)
> + if (AMDGPU_MN_KEY(amn->mirror.hmm->mmu_notifier.mm,
> + amn->type) == key)
> goto release_locks;
>
> amn = kzalloc(sizeof(*amn), GFP_KERNEL);
> @@ -337,10 +205,8 @@ struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
> }
>
> amn->adev = adev;
> - amn->mm = mm;
> init_rwsem(&amn->lock);
> amn->type = type;
> - amn->objects = RB_ROOT_CACHED;
>
> amn->mirror.ops = &amdgpu_hmm_mirror_ops[type];
> r = hmm_mirror_register(&amn->mirror, mm);
> @@ -369,100 +235,33 @@ struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
> * @bo: amdgpu buffer object
> * @addr: userptr addr we should monitor
> *
> - * Registers an HMM mirror for the given BO at the specified address.
> + * Registers a mmu_notifier for the given BO at the specified address.
> * Returns 0 on success, -ERRNO if anything goes wrong.
> */
> int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
> {
> - unsigned long end = addr + amdgpu_bo_size(bo) - 1;
> - struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> - enum amdgpu_mn_type type =
> - bo->kfd_bo ? AMDGPU_MN_TYPE_HSA : AMDGPU_MN_TYPE_GFX;
> - struct amdgpu_mn *amn;
> - struct amdgpu_mn_node *node = NULL, *new_node;
> - struct list_head bos;
> - struct interval_tree_node *it;
> -
> - amn = amdgpu_mn_get(adev, type);
> - if (IS_ERR(amn))
> - return PTR_ERR(amn);
> -
> - new_node = kmalloc(sizeof(*new_node), GFP_KERNEL);
> - if (!new_node)
> - return -ENOMEM;
> -
> - INIT_LIST_HEAD(&bos);
> -
> - down_write(&amn->lock);
> -
> - while ((it = interval_tree_iter_first(&amn->objects, addr, end))) {
> - kfree(node);
> - node = container_of(it, struct amdgpu_mn_node, it);
> - interval_tree_remove(&node->it, &amn->objects);
> - addr = min(it->start, addr);
> - end = max(it->last, end);
> - list_splice(&node->bos, &bos);
> - }
> -
> - if (!node)
> - node = new_node;
> + if (bo->kfd_bo)
> + bo->notifier.ops = &amdgpu_mn_hsa_ops;
> else
> - kfree(new_node);
> -
> - bo->mn = amn;
> -
> - node->it.start = addr;
> - node->it.last = end;
> - INIT_LIST_HEAD(&node->bos);
> - list_splice(&bos, &node->bos);
> - list_add(&bo->mn_list, &node->bos);
> + bo->notifier.ops = &amdgpu_mn_gfx_ops;
>
> - interval_tree_insert(&node->it, &amn->objects);
> -
> - up_write(&amn->lock);
> -
> - return 0;
> + return mmu_range_notifier_insert(&bo->notifier, addr,
> + amdgpu_bo_size(bo), current->mm);
> }
>
> /**
> - * amdgpu_mn_unregister - unregister a BO for HMM mirror updates
> + * amdgpu_mn_unregister - unregister a BO for notifier updates
> *
> * @bo: amdgpu buffer object
> *
> - * Remove any registration of HMM mirror updates from the buffer object.
> + * Remove any registration of mmu notifier updates from the buffer object.
> */
> void amdgpu_mn_unregister(struct amdgpu_bo *bo)
> {
> - struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> - struct amdgpu_mn *amn;
> - struct list_head *head;
> -
> - mutex_lock(&adev->mn_lock);
> -
> - amn = bo->mn;
> - if (amn == NULL) {
> - mutex_unlock(&adev->mn_lock);
> + if (!bo->notifier.mm)
> return;
> - }
> -
> - down_write(&amn->lock);
> -
> - /* save the next list entry for later */
> - head = bo->mn_list.next;
> -
> - bo->mn = NULL;
> - list_del_init(&bo->mn_list);
> -
> - if (list_empty(head)) {
> - struct amdgpu_mn_node *node;
> -
> - node = container_of(head, struct amdgpu_mn_node, bos);
> - interval_tree_remove(&node->it, &amn->objects);
> - kfree(node);
> - }
> -
> - up_write(&amn->lock);
> - mutex_unlock(&adev->mn_lock);
> + mmu_range_notifier_remove(&bo->notifier);
> + bo->notifier.mm = NULL;
> }
>
> /* flags used by HMM internal, not related to CPU/GPU PTE flags */
[snip]
