On 2018-10-17 04:15 AM, Christian König wrote:
> Am 17.10.18 um 04:56 schrieb Yang, Philip:
>> Use HMM helper function hmm_vma_fault() to get physical pages backing
>> userptr and start CPU page table update track of those pages. Then use
>> hmm_vma_range_done() to check if those pages are updated before
>> amdgpu_cs_submit for gfx or before user queues are resumed for kfd.
>>
>> If userptr pages are updated, for gfx, amdgpu_cs_ioctl will restart
>> from scratch, for kfd, restore worker is rescheduled to retry.
>>
>> To avoid circular lock dependency, the locking order is:
>> mmap_sem -> amdgpu_mn_lock(p->mn) -> bo::reserve
>> mmap_sem -> bo::reserve
>
> I'm not sure that this will work, we used to have some dependencies on
> bo::reserve -> mmap_sem.
>
> See the following patch as well:
>
> commit 2f568dbd6b944c2e8c0c54b53c2211c23995e6a4
> Author: Christian König <christian.koenig@xxxxxxx>
> Date: Tue Feb 23 12:36:59 2016 +0100
>
> drm/amdgpu: move get_user_pages out of amdgpu_ttm_tt_pin_userptr v6
>
> That avoids lock inversion between the BO reservation lock
> and the anon_vma lock.
>
> A whole bunch of more problems below.
>
Thanks for the review.
I will remove the nested lock between mmap_sem and bo::reserve, and
change the kfd side locking order
to bo::reserve -> amdgpu_mn_lock(p->mn) as the original gfx side locking
order.
Will submit patch v2 with other changes.
Philip
>>
>> HMM simplify the CPU page table concurrently update check, so remove
>> guptasklock, mmu_invalidations, last_set_pages fields from
>> amdgpu_ttm_tt struct.
>>
>> HMM doesnot pin the page (increase page ref count), so remove related
>> operations like release_pages(), put_page(), mark_page_dirty().
>>
>> Change-Id: Iffd5f855cc9ce402cdfca167f68f83fe39ac56f9
>> Signed-off-by: Philip Yang <Philip.Yang@xxxxxxx>
>> ---
>> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 101 ++++++++++---
>> drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c | 2 -
>> drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h | 3 +-
>> drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 171
>> +++++++++--------------
>> drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 14 +-
>> drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c | 34 ++++-
>> drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h | 7 +-
>> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 164
>> +++++++++-------------
>> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h | 3 +-
>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 1 -
>> 10 files changed, 252 insertions(+), 248 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> index df0a059..3fd0340 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> @@ -615,8 +615,7 @@ static int init_user_pages(struct kgd_mem *mem,
>> struct mm_struct *mm,
>> amdgpu_bo_unreserve(bo);
>> release_out:
>> - if (ret)
>> - release_pages(mem->user_pages, bo->tbo.ttm->num_pages);
>> + amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
>> free_out:
>> kvfree(mem->user_pages);
>> mem->user_pages = NULL;
>> @@ -678,7 +677,6 @@ static int reserve_bo_and_vm(struct kgd_mem *mem,
>> ctx->kfd_bo.priority = 0;
>> ctx->kfd_bo.tv.bo = &bo->tbo;
>> ctx->kfd_bo.tv.shared = true;
>> - ctx->kfd_bo.user_pages = NULL;
>> list_add(&ctx->kfd_bo.tv.head, &ctx->list);
>> amdgpu_vm_get_pd_bo(vm, &ctx->list, &ctx->vm_pd[0]);
>> @@ -742,7 +740,6 @@ static int reserve_bo_and_cond_vms(struct kgd_mem
>> *mem,
>> ctx->kfd_bo.priority = 0;
>> ctx->kfd_bo.tv.bo = &bo->tbo;
>> ctx->kfd_bo.tv.shared = true;
>> - ctx->kfd_bo.user_pages = NULL;
>> list_add(&ctx->kfd_bo.tv.head, &ctx->list);
>> i = 0;
>> @@ -1311,9 +1308,6 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
>> /* Free user pages if necessary */
>> if (mem->user_pages) {
>> pr_debug("%s: Freeing user_pages array\n", __func__);
>> - if (mem->user_pages[0])
>> - release_pages(mem->user_pages,
>> - mem->bo->tbo.ttm->num_pages);
>> kvfree(mem->user_pages);
>> }
>> @@ -1739,8 +1733,6 @@ static int update_invalid_user_pages(struct
>> amdkfd_process_info *process_info,
>> __func__);
>> return -ENOMEM;
>> }
>> - } else if (mem->user_pages[0]) {
>> - release_pages(mem->user_pages, bo->tbo.ttm->num_pages);
>> }
>> /* Get updated user pages */
>> @@ -1756,12 +1748,6 @@ static int update_invalid_user_pages(struct
>> amdkfd_process_info *process_info,
>> * stalled user mode queues.
>> */
>> }
>> -
>> - /* Mark the BO as valid unless it was invalidated
>> - * again concurrently
>> - */
>> - if (atomic_cmpxchg(&mem->invalid, invalid, 0) != invalid)
>> - return -EAGAIN;
>> }
>> return 0;
>> @@ -1854,14 +1840,10 @@ static int validate_invalid_user_pages(struct
>> amdkfd_process_info *process_info)
>> }
>> /* Validate succeeded, now the BO owns the pages, free
>> - * our copy of the pointer array. Put this BO back on
>> - * the userptr_valid_list. If we need to revalidate
>> - * it, we need to start from scratch.
>> + * our copy of the pointer array.
>> */
>> kvfree(mem->user_pages);
>> mem->user_pages = NULL;
>> - list_move_tail(&mem->validate_list.head,
>> - &process_info->userptr_valid_list);
>
> I'm not an expert on the KFD stuff, but that doesn't looks correct to me.
>
>> /* Update mapping. If the BO was not validated
>> * (because we couldn't get user pages), this will
>> @@ -1902,6 +1884,70 @@ static int validate_invalid_user_pages(struct
>> amdkfd_process_info *process_info)
>> return ret;
>> }
>> +/* user_pages_invalidated - if CPU page table is updated after
>> getting user
>> + * pages
>> + *
>> + * HMM mirror callback lock amn is hold to prevent the concurrent CPU
>> + * page table update while resuming user queues.
>> + *
>> + * Returns: true if CPU page table is updated, false otherwise
>> + */
>> +static int user_pages_invalidated(struct mm_struct *mm,
>> + struct amdkfd_process_info *process_info,
>> + struct amdgpu_mn **amn)
>> +{
>> + struct kgd_mem *mem, *tmp_mem;
>> + struct amdgpu_bo *bo;
>> + struct amdgpu_device *adev;
>> + int invalid, r = 0;
>> +
>> + list_for_each_entry_safe(mem, tmp_mem,
>> + &process_info->userptr_inval_list,
>> + validate_list.head) {
>> +
>> + invalid = atomic_read(&mem->invalid);
>> + if (!invalid)
>> + /* BO hasn't been invalidated since the last
>> + * revalidation attempt. Keep its BO list.
>> + */
>> + continue;
>> +
>> + bo = mem->bo;
>> +
>> + /* Get HMM mirror callback lock */
>> + if (!*amn) {
>> + adev = amdgpu_ttm_adev(bo->tbo.bdev);
>> + *amn = amdgpu_mn_get(mm, adev, AMDGPU_MN_TYPE_HSA);
>> + if (IS_ERR(*amn)) {
>> + r = true;
>> + *amn = NULL;
>> + goto out;
>> + }
>> +
>> + amdgpu_mn_lock(*amn);
>> + }
>> +
>> + r |= amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
>> +
>> + /* Put this BO back on the userptr_valid_list. If we need to
>> + * revalidate it, we need to start from scratch.
>> + */
>> + list_move_tail(&mem->validate_list.head,
>> + &process_info->userptr_valid_list);
>> +
>> + /* Mark the BO as valid unless it was invalidated
>> + * again concurrently
>> + */
>> + if (atomic_cmpxchg(&mem->invalid, invalid, 0) != invalid) {
>> + r = true;
>> + goto out;
>> + }
>> + }
>> +
>> +out:
>> + return r;
>> +}
>> +
>> /* Worker callback to restore evicted userptr BOs
>> *
>> * Tries to update and validate all userptr BOs. If successful and no
>> @@ -1917,6 +1963,7 @@ static void
>> amdgpu_amdkfd_restore_userptr_worker(struct work_struct *work)
>> struct task_struct *usertask;
>> struct mm_struct *mm;
>> int evicted_bos;
>> + struct amdgpu_mn *amn = NULL;
>> evicted_bos = atomic_read(&process_info->evicted_bos);
>> if (!evicted_bos)
>> @@ -1955,13 +2002,27 @@ static void
>> amdgpu_amdkfd_restore_userptr_worker(struct work_struct *work)
>> if (atomic_cmpxchg(&process_info->evicted_bos, evicted_bos, 0) !=
>> evicted_bos)
>> goto unlock_out;
>> +
>> + /* If CPU page table is updated again after getting user pages,
>> + * schedule to restart the restore process again.
>> + *
>> + * amn is also locked to prevent CPU page table update while
>> resuming
>> + * user queues. amn is unlocked after user queues are resumed.
>> + */
>> + if (user_pages_invalidated(mm, process_info, &amn))
>> + goto unlock_mn_out;
>> +
>> evicted_bos = 0;
>> +
>> if (kgd2kfd->resume_mm(mm)) {
>> pr_err("%s: Failed to resume KFD\n", __func__);
>> /* No recovery from this failure. Probably the CP is
>> * hanging. No point trying again.
>> */
>> }
>> +
>> +unlock_mn_out:
>> + amdgpu_mn_unlock(amn);
>> unlock_out:
>> mutex_unlock(&process_info->lock);
>> mmput(mm);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
>> index 14d2982..2716c24 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
>> @@ -201,8 +201,6 @@ void amdgpu_bo_list_get_list(struct
>> amdgpu_bo_list *list,
>> if (!bo->parent)
>> list_add_tail(&e->tv.head, &bucket[priority]);
>> -
>> - e->user_pages = NULL;
>> }
>> /* Connect the sorted buckets in the output list. */
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
>> index 7c5f5d1..4beab2d 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
>> @@ -35,8 +35,7 @@ struct amdgpu_bo_list_entry {
>> struct ttm_validate_buffer tv;
>> struct amdgpu_bo_va *bo_va;
>> uint32_t priority;
>> - struct page **user_pages;
>> - int user_invalidated;
>> + bool user_invalidated;
>> };
>> struct amdgpu_bo_list {
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>> index 8836186..c46af18 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
>> @@ -51,7 +51,6 @@ static int amdgpu_cs_user_fence_chunk(struct
>> amdgpu_cs_parser *p,
>> p->uf_entry.priority = 0;
>> p->uf_entry.tv.bo = &bo->tbo;
>> p->uf_entry.tv.shared = true;
>> - p->uf_entry.user_pages = NULL;
>> drm_gem_object_put_unlocked(gobj);
>> @@ -531,24 +530,19 @@ static int amdgpu_cs_list_validate(struct
>> amdgpu_cs_parser *p,
>> list_for_each_entry(lobj, validated, tv.head) {
>> struct amdgpu_bo *bo = ttm_to_amdgpu_bo(lobj->tv.bo);
>> - bool binding_userptr = false;
>> struct mm_struct *usermm;
>> usermm = amdgpu_ttm_tt_get_usermm(bo->tbo.ttm);
>> if (usermm && usermm != current->mm)
>> return -EPERM;
>> - /* Check if we have user pages and nobody bound the BO
>> already */
>> - if (amdgpu_ttm_tt_userptr_needs_pages(bo->tbo.ttm) &&
>> - lobj->user_pages) {
>> + if (amdgpu_ttm_tt_is_userptr(bo->tbo.ttm) &&
>> + lobj->user_invalidated) {
>> amdgpu_bo_placement_from_domain(bo,
>> AMDGPU_GEM_DOMAIN_CPU);
>> r = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
>> if (r)
>> return r;
>> - amdgpu_ttm_tt_set_user_pages(bo->tbo.ttm,
>> - lobj->user_pages);
>> - binding_userptr = true;
>> }
>> if (p->evictable == lobj)
>> @@ -557,11 +551,6 @@ static int amdgpu_cs_list_validate(struct
>> amdgpu_cs_parser *p,
>> r = amdgpu_cs_validate(p, bo);
>> if (r)
>> return r;
>> -
>> - if (binding_userptr) {
>> - kvfree(lobj->user_pages);
>> - lobj->user_pages = NULL;
>> - }
>> }
>> return 0;
>> }
>> @@ -576,7 +565,6 @@ static int amdgpu_cs_parser_bos(struct
>> amdgpu_cs_parser *p,
>> struct amdgpu_bo *gds;
>> struct amdgpu_bo *gws;
>> struct amdgpu_bo *oa;
>> - unsigned tries = 10;
>> int r;
>> INIT_LIST_HEAD(&p->validated);
>> @@ -585,7 +573,6 @@ static int amdgpu_cs_parser_bos(struct
>> amdgpu_cs_parser *p,
>> if (cs->in.bo_list_handle) {
>> if (p->bo_list)
>> return -EINVAL;
>> -
>> r = amdgpu_bo_list_get(fpriv, cs->in.bo_list_handle,
>> &p->bo_list);
>> if (r)
>> @@ -599,8 +586,10 @@ static int amdgpu_cs_parser_bos(struct
>> amdgpu_cs_parser *p,
>> }
>> amdgpu_bo_list_get_list(p->bo_list, &p->validated);
>> - if (p->bo_list->first_userptr != p->bo_list->num_entries)
>> - p->mn = amdgpu_mn_get(p->adev, AMDGPU_MN_TYPE_GFX);
>> + if (p->bo_list->first_userptr != p->bo_list->num_entries) {
>> + p->mn = amdgpu_mn_get(current->mm, p->adev,
>> + AMDGPU_MN_TYPE_GFX);
>> + }
>
> Please don't add {} here.
>
>> INIT_LIST_HEAD(&duplicates);
>> amdgpu_vm_get_pd_bo(&fpriv->vm, &p->validated, &p->vm_pd);
>> @@ -608,79 +597,41 @@ static int amdgpu_cs_parser_bos(struct
>> amdgpu_cs_parser *p,
>> if (p->uf_entry.tv.bo &&
>> !ttm_to_amdgpu_bo(p->uf_entry.tv.bo)->parent)
>> list_add(&p->uf_entry.tv.head, &p->validated);
>> - while (1) {
>> - struct list_head need_pages;
>> -
>> - r = ttm_eu_reserve_buffers(&p->ticket, &p->validated, true,
>> - &duplicates);
>> - if (unlikely(r != 0)) {
>> - if (r != -ERESTARTSYS)
>> - DRM_ERROR("ttm_eu_reserve_buffers failed.\n");
>> - goto error_free_pages;
>> - }
>> -
>> - INIT_LIST_HEAD(&need_pages);
>> - amdgpu_bo_list_for_each_userptr_entry(e, p->bo_list) {
>> - struct amdgpu_bo *bo = ttm_to_amdgpu_bo(e->tv.bo);
>> -
>> - if (amdgpu_ttm_tt_userptr_invalidated(bo->tbo.ttm,
>> - &e->user_invalidated) && e->user_pages) {
>> -
>> - /* We acquired a page array, but somebody
>> - * invalidated it. Free it and try again
>> - */
>> - release_pages(e->user_pages,
>> - bo->tbo.ttm->num_pages);
>> - kvfree(e->user_pages);
>> - e->user_pages = NULL;
>> - }
>> + /* Get userptr backing pages. If pages are updated after registered
>> + * in amdgpu_gem_userptr_ioctl(), amdgpu_cs_list_validate() will do
>> + * amdgpu_ttm_backend_bind() to flush and invalidate new pages
>> + */
>> + amdgpu_bo_list_for_each_userptr_entry(e, p->bo_list) {
>> + struct amdgpu_bo *bo = ttm_to_amdgpu_bo(e->tv.bo);
>> + struct page *user_pages[bo->tbo.ttm->num_pages];
>
> Dynamic allocation of arrays on the stack is illegal in the kernel.
Will change to kvmalloc_array and kvfree because we don't know the max
userptr pages.
You are right, it's bad idea to use VLA in kernel.
>
>> + int i;
>> + bool user_invalidated = false;
>> - if (amdgpu_ttm_tt_userptr_needs_pages(bo->tbo.ttm) &&
>> - !e->user_pages) {
>> - list_del(&e->tv.head);
>> - list_add(&e->tv.head, &need_pages);
>> + r = amdgpu_ttm_tt_get_user_pages(bo->tbo.ttm, user_pages);
>> + if (r)
>> + return r;
>> - amdgpu_bo_unreserve(bo);
>> + for (i = 0; i < bo->tbo.ttm->num_pages; i++) {
>> + if (bo->tbo.ttm->pages[i] != user_pages[i]) {
>> + bo->tbo.ttm->pages[i] = user_pages[i];
>> + user_invalidated = true;
>
> The BO is not reserved, isn't it? So that is not protected by any locks?
>
>> }
>> }
>> + e->user_invalidated = user_invalidated;
>> + }
>> - if (list_empty(&need_pages))
>> - break;
>> -
>> - /* Unreserve everything again. */
>> - ttm_eu_backoff_reservation(&p->ticket, &p->validated);
>> -
>> - /* We tried too many times, just abort */
>> - if (!--tries) {
>> - r = -EDEADLK;
>> - DRM_ERROR("deadlock in %s\n", __func__);
>> - goto error_free_pages;
>> - }
>> -
>> - /* Fill the page arrays for all userptrs. */
>> - list_for_each_entry(e, &need_pages, tv.head) {
>> - struct ttm_tt *ttm = e->tv.bo->ttm;
>> -
>> - e->user_pages = kvmalloc_array(ttm->num_pages,
>> - sizeof(struct page*),
>> - GFP_KERNEL | __GFP_ZERO);
>> - if (!e->user_pages) {
>> - r = -ENOMEM;
>> - DRM_ERROR("calloc failure in %s\n", __func__);
>> - goto error_free_pages;
>> - }
>> -
>> - r = amdgpu_ttm_tt_get_user_pages(ttm, e->user_pages);
>> - if (r) {
>> - DRM_ERROR("amdgpu_ttm_tt_get_user_pages failed.\n");
>> - kvfree(e->user_pages);
>> - e->user_pages = NULL;
>> - goto error_free_pages;
>> - }
>> - }
>> + /* No memory allocation is allowed while holding the mn lock.
>> + * p->mn is hold until amdgpu_cs_submit is finished and fence is
>> added
>> + * to BOs.
>> + */
>> + amdgpu_mn_lock(p->mn);
>
> That won't work. We allocate tons of memory after this point during BO
> validation.
>
> Christian.
>
>> - /* And try again. */
>> - list_splice(&need_pages, &p->validated);
>> + r = ttm_eu_reserve_buffers(&p->ticket, &p->validated, true,
>> + &duplicates);
>> + if (unlikely(r != 0)) {
>> + if (r != -ERESTARTSYS)
>> + DRM_ERROR("ttm_eu_reserve_buffers failed.\n");
>> + goto out;
>> }
>> amdgpu_cs_get_threshold_for_moves(p->adev,
>> &p->bytes_moved_threshold,
>> @@ -743,16 +694,9 @@ static int amdgpu_cs_parser_bos(struct
>> amdgpu_cs_parser *p,
>> error_validate:
>> if (r)
>> ttm_eu_backoff_reservation(&p->ticket, &p->validated);
>> -
>> -error_free_pages:
>> -
>> - amdgpu_bo_list_for_each_userptr_entry(e, p->bo_list) {
>> - if (!e->user_pages)
>> - continue;
>> -
>> - release_pages(e->user_pages, e->tv.bo->ttm->num_pages);
>> - kvfree(e->user_pages);
>> - }
>> +out:
>> + if (r)
>> + amdgpu_mn_unlock(p->mn);
>> return r;
>> }
>> @@ -1206,8 +1150,7 @@ static int amdgpu_cs_submit(struct
>> amdgpu_cs_parser *p,
>> struct amdgpu_bo_list_entry *e;
>> struct amdgpu_job *job;
>> uint64_t seq;
>> -
>> - int r;
>> + int r = 0;
>> job = p->job;
>> p->job = NULL;
>> @@ -1216,15 +1159,18 @@ static int amdgpu_cs_submit(struct
>> amdgpu_cs_parser *p,
>> if (r)
>> goto error_unlock;
>> - /* No memory allocation is allowed while holding the mn lock */
>> - amdgpu_mn_lock(p->mn);
>> + /* If userptr are updated after amdgpu_cs_parser_bos(), restart
>> cs */
>> amdgpu_bo_list_for_each_userptr_entry(e, p->bo_list) {
>> struct amdgpu_bo *bo = ttm_to_amdgpu_bo(e->tv.bo);
>> - if (amdgpu_ttm_tt_userptr_needs_pages(bo->tbo.ttm)) {
>> - r = -ERESTARTSYS;
>> - goto error_abort;
>> - }
>> + e->user_invalidated =
>> + amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
>> +
>> + r |= e->user_invalidated;
>> + }
>> + if (r) {
>> + r = -ERESTARTSYS;
>> + goto error_abort;
>> }
>> job->owner = p->filp;
>> @@ -1272,14 +1218,20 @@ static int amdgpu_cs_submit(struct
>> amdgpu_cs_parser *p,
>> int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct
>> drm_file *filp)
>> {
>> struct amdgpu_device *adev = dev->dev_private;
>> - union drm_amdgpu_cs *cs = data;
>> - struct amdgpu_cs_parser parser = {};
>> - bool reserved_buffers = false;
>> + union drm_amdgpu_cs *cs;
>> + struct amdgpu_cs_parser parser;
>> + bool reserved_buffers;
>> + int tries = 10;
>> int i, r;
>> if (!adev->accel_working)
>> return -EBUSY;
>> +restart:
>> + memset(&parser, 0, sizeof(parser));
>> + cs = data;
>> + reserved_buffers = false;
>> +
>> parser.adev = adev;
>> parser.filp = filp;
>> @@ -1321,6 +1273,15 @@ int amdgpu_cs_ioctl(struct drm_device *dev,
>> void *data, struct drm_file *filp)
>> out:
>> amdgpu_cs_parser_fini(&parser, r, reserved_buffers);
>> +
>> + if (r == -ERESTARTSYS) {
>> + if (!--tries) {
>> + DRM_ERROR("Possible deadlock? Retry too many times\n");
>> + return -EDEADLK;
>> + }
>> + goto restart;
>> + }
>> +
>> return r;
>> }
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> index 7b3d1eb..ff9a8fd 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> @@ -336,26 +336,24 @@ int amdgpu_gem_userptr_ioctl(struct drm_device
>> *dev, void *data,
>> r = amdgpu_bo_reserve(bo, true);
>> if (r)
>> - goto free_pages;
>> + goto user_pages_done;
>> amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_GTT);
>> r = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
>> amdgpu_bo_unreserve(bo);
>> if (r)
>> - goto free_pages;
>> + goto user_pages_done;
>> }
>> r = drm_gem_handle_create(filp, gobj, &handle);
>> - /* drop reference from allocate - handle holds it now */
>> - drm_gem_object_put_unlocked(gobj);
>> if (r)
>> - return r;
>> + goto user_pages_done;
>> args->handle = handle;
>> - return 0;
>> -free_pages:
>> - release_pages(bo->tbo.ttm->pages, bo->tbo.ttm->num_pages);
>> +user_pages_done:
>> + if (args->flags & AMDGPU_GEM_USERPTR_VALIDATE)
>> + amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
>> release_object:
>> drm_gem_object_put_unlocked(gobj);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>> index 56595b3..6b6becd 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>> @@ -229,8 +229,6 @@ static void amdgpu_mn_invalidate_node(struct
>> amdgpu_mn_node *node,
>> true, false, MAX_SCHEDULE_TIMEOUT);
>> if (r <= 0)
>> DRM_ERROR("(%ld) failed to wait for user bo\n", r);
>> -
>> - amdgpu_ttm_tt_mark_user_pages(bo->tbo.ttm);
>> }
>> }
>> @@ -355,15 +353,16 @@ static struct hmm_mirror_ops
>> amdgpu_hmm_mirror_ops[] = {
>> /**
>> * amdgpu_mn_get - create HMM mirror context
>> *
>> + * @mm: the mm struct
>> * @adev: amdgpu device pointer
>> * @type: type of MMU notifier context
>> *
>> - * Creates a HMM mirror context for current->mm.
>> + * Creates a HMM mirror context for mm.
>> */
>> -struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
>> +struct amdgpu_mn *amdgpu_mn_get(struct mm_struct *mm,
>> + struct amdgpu_device *adev,
>> enum amdgpu_mn_type type)
>> {
>> - struct mm_struct *mm = current->mm;
>> struct amdgpu_mn *amn;
>> unsigned long key = AMDGPU_MN_KEY(mm, type);
>> int r;
>> @@ -433,7 +432,7 @@ int amdgpu_mn_register(struct amdgpu_bo *bo,
>> unsigned long addr)
>> struct list_head bos;
>> struct interval_tree_node *it;
>> - amn = amdgpu_mn_get(adev, type);
>> + amn = amdgpu_mn_get(current->mm, adev, type);
>> if (IS_ERR(amn))
>> return PTR_ERR(amn);
>> @@ -515,3 +514,26 @@ void amdgpu_mn_unregister(struct amdgpu_bo *bo)
>> mutex_unlock(&adev->mn_lock);
>> }
>> +/* flags used by HMM internal, not related to CPU/GPU PTE flags */
>> +static const uint64_t hmm_range_flags[HMM_PFN_FLAG_MAX] = {
>> + (1 << 0), /* HMM_PFN_VALID */
>> + (1 << 1), /* HMM_PFN_WRITE */
>> + 0 /* HMM_PFN_DEVICE_PRIVATE */
>> +};
>> +
>> +static const uint64_t hmm_range_values[HMM_PFN_VALUE_MAX] = {
>> + 0xfffffffffffffffeUL, /* HMM_PFN_ERROR */
>> + 0, /* HMM_PFN_NONE */
>> + 0xfffffffffffffffcUL /* HMM_PFN_SPECIAL */
>> +};
>> +
>> +void amdgpu_hmm_init_range(struct hmm_range *range)
>> +{
>> + if (range) {
>> + range->flags = hmm_range_flags;
>> + range->values = hmm_range_values;
>> + range->pfn_shift = PAGE_SHIFT;
>> + range->pfns = NULL;
>> + INIT_LIST_HEAD(&range->list);
>> + }
>> +}
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
>> index 0e27526..59ea30e 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
>> @@ -25,9 +25,10 @@
>> #define __AMDGPU_MN_H__
>> /*
>> - * MMU Notifier
>> + * HMM mirror
>> */
>> struct amdgpu_mn;
>> +struct hmm_range;
>> enum amdgpu_mn_type {
>> AMDGPU_MN_TYPE_GFX,
>> @@ -37,10 +38,12 @@ enum amdgpu_mn_type {
>> #if defined(CONFIG_HMM)
>> void amdgpu_mn_lock(struct amdgpu_mn *mn);
>> void amdgpu_mn_unlock(struct amdgpu_mn *mn);
>> -struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
>> +struct amdgpu_mn *amdgpu_mn_get(struct mm_struct *mm,
>> + struct amdgpu_device *adev,
>> enum amdgpu_mn_type type);
>> int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr);
>> void amdgpu_mn_unregister(struct amdgpu_bo *bo);
>> +void amdgpu_hmm_init_range(struct hmm_range *range);
>> #else
>> static inline void amdgpu_mn_lock(struct amdgpu_mn *mn) {}
>> static inline void amdgpu_mn_unlock(struct amdgpu_mn *mn) {}
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> index 3a68028..b0537d1 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> @@ -43,6 +43,7 @@
>> #include <linux/pagemap.h>
>> #include <linux/debugfs.h>
>> #include <linux/iommu.h>
>> +#include <linux/hmm.h>
>> #include "amdgpu.h"
>> #include "amdgpu_object.h"
>> #include "amdgpu_trace.h"
>> @@ -799,11 +800,6 @@ static unsigned long
>> amdgpu_ttm_io_mem_pfn(struct ttm_buffer_object *bo,
>> /*
>> * TTM backend functions.
>> */
>> -struct amdgpu_ttm_gup_task_list {
>> - struct list_head list;
>> - struct task_struct *task;
>> -};
>> -
>> struct amdgpu_ttm_tt {
>> struct ttm_dma_tt ttm;
>> u64 offset;
>> @@ -812,85 +808,91 @@ struct amdgpu_ttm_tt {
>> uint32_t userflags;
>> spinlock_t guptasklock;
>> struct list_head guptasks;
>> - atomic_t mmu_invalidations;
>> - uint32_t last_set_pages;
>> + struct hmm_range range;
>> };
>> /**
>> - * amdgpu_ttm_tt_get_user_pages - Pin pages of memory pointed to by
>> a USERPTR
>> - * pointer to memory
>> + * amdgpu_ttm_tt_get_user_pages - get device accessible pages that
>> back user
>> + * memory and start HMM tracking CPU page table update
>> *
>> - * Called by amdgpu_gem_userptr_ioctl() and amdgpu_cs_parser_bos().
>> - * This provides a wrapper around the get_user_pages() call to provide
>> - * device accessible pages that back user memory.
>> + * Calling function must call amdgpu_ttm_tt_userptr_range_done()
>> once and only
>> + * once afterwards to stop HMM tracking
>> */
>> int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page
>> **pages)
>> {
>> struct amdgpu_ttm_tt *gtt = (void *)ttm;
>> struct mm_struct *mm = gtt->usertask->mm;
>> - unsigned int flags = 0;
>> - unsigned pinned = 0;
>> - int r;
>> + unsigned long end = gtt->userptr + ttm->num_pages * PAGE_SIZE;
>> + struct hmm_range *range = >t->range;
>> + int r, i;
>> if (!mm) /* Happens during process shutdown */
>> return -ESRCH;
>> - if (!(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY))
>> - flags |= FOLL_WRITE;
>> + amdgpu_hmm_init_range(range);
>> down_read(&mm->mmap_sem);
>> - if (gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) {
>> - /*
>> - * check that we only use anonymous memory to prevent problems
>> - * with writeback
>> - */
>> - unsigned long end = gtt->userptr + ttm->num_pages * PAGE_SIZE;
>> - struct vm_area_struct *vma;
>> + range->vma = find_vma(mm, gtt->userptr);
>> + if (!range->vma || range->vma->vm_file || range->vma->vm_end <
>> end) {
>> + r = -EPERM;
>> + goto out;
>> + }
>> + range->pfns = kvmalloc_array(ttm->num_pages, sizeof(uint64_t),
>> + GFP_KERNEL | __GFP_ZERO);
>> + if (range->pfns == NULL) {
>> + r = -ENOMEM;
>> + goto out;
>> + }
>> + range->start = gtt->userptr;
>> + range->end = end;
>> - vma = find_vma(mm, gtt->userptr);
>> - if (!vma || vma->vm_file || vma->vm_end < end) {
>> - up_read(&mm->mmap_sem);
>> - return -EPERM;
>> - }
>> + for (i = 0; i < ttm->num_pages; i++) {
>> + range->pfns[i] = range->flags[HMM_PFN_VALID];
>> + range->pfns[i] |= amdgpu_ttm_tt_is_readonly(ttm) ?
>> + 0 : range->flags[HMM_PFN_WRITE];
>> }
>> - /* loop enough times using contiguous pages of memory */
>> - do {
>> - unsigned num_pages = ttm->num_pages - pinned;
>> - uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE;
>> - struct page **p = pages + pinned;
>> - struct amdgpu_ttm_gup_task_list guptask;
>> + /* This may triggles page table update */
>> + r = hmm_vma_fault(range, true);
>> + if (r)
>> + goto out_free_pfns;
>> - guptask.task = current;
>> - spin_lock(>t->guptasklock);
>> - list_add(&guptask.list, >t->guptasks);
>> - spin_unlock(>t->guptasklock);
>> + for (i = 0; i < ttm->num_pages; i++)
>> + pages[i] = hmm_pfn_to_page(range, range->pfns[i]);
>> - if (mm == current->mm)
>> - r = get_user_pages(userptr, num_pages, flags, p, NULL);
>> - else
>> - r = get_user_pages_remote(gtt->usertask,
>> - mm, userptr, num_pages,
>> - flags, p, NULL, NULL);
>> + up_read(&mm->mmap_sem);
>> + return 0;
>> - spin_lock(>t->guptasklock);
>> - list_del(&guptask.list);
>> - spin_unlock(>t->guptasklock);
>> +out_free_pfns:
>> + kvfree(range->pfns);
>> + range->pfns = NULL;
>> +out:
>> + up_read(&mm->mmap_sem);
>> + return r;
>> +}
>> - if (r < 0)
>> - goto release_pages;
>> +/**
>> + * amdgpu_ttm_tt_userptr_range_done - stop HMM track the CPU page
>> table change
>> + * Check if the pages backing this ttm range have been invalidated
>> + *
>> + * Returns: true if pages are invalidated since the last time
>> they've been set
>> + */
>> +bool amdgpu_ttm_tt_get_user_pages_done(struct ttm_tt *ttm)
>> +{
>> + struct amdgpu_ttm_tt *gtt = (void *)ttm;
>> + int r;
>> - pinned += r;
>> + if (gtt == NULL || !gtt->userptr)
>> + return false;
>> - } while (pinned < ttm->num_pages);
>> + r = !hmm_vma_range_done(>t->range);
>> - up_read(&mm->mmap_sem);
>> - return 0;
>> + if (gtt->range.pfns) {
>> + kvfree(gtt->range.pfns);
>> + gtt->range.pfns = NULL;
>> + }
>> -release_pages:
>> - release_pages(pages, pinned);
>> - up_read(&mm->mmap_sem);
>> return r;
>> }
>> @@ -903,16 +905,10 @@ int amdgpu_ttm_tt_get_user_pages(struct
>> ttm_tt *ttm, struct page **pages)
>> */
>> void amdgpu_ttm_tt_set_user_pages(struct ttm_tt *ttm, struct page
>> **pages)
>> {
>> - struct amdgpu_ttm_tt *gtt = (void *)ttm;
>> unsigned i;
>> - gtt->last_set_pages = atomic_read(>t->mmu_invalidations);
>> - for (i = 0; i < ttm->num_pages; ++i) {
>> - if (ttm->pages[i])
>> - put_page(ttm->pages[i]);
>> -
>> + for (i = 0; i < ttm->num_pages; ++i)
>> ttm->pages[i] = pages ? pages[i] : NULL;
>> - }
>> }
>> /**
>> @@ -997,9 +993,6 @@ static void amdgpu_ttm_tt_unpin_userptr(struct
>> ttm_tt *ttm)
>> /* unmap the pages mapped to the device */
>> dma_unmap_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents, direction);
>> - /* mark the pages as dirty */
>> - amdgpu_ttm_tt_mark_user_pages(ttm);
>> -
>> sg_free_table(ttm->sg);
>> }
>> @@ -1352,8 +1345,6 @@ int amdgpu_ttm_tt_set_userptr(struct ttm_tt
>> *ttm, uint64_t addr,
>> spin_lock_init(>t->guptasklock);
>> INIT_LIST_HEAD(>t->guptasks);
>> - atomic_set(>t->mmu_invalidations, 0);
>> - gtt->last_set_pages = 0;
>> return 0;
>> }
>> @@ -1383,7 +1374,6 @@ bool amdgpu_ttm_tt_affect_userptr(struct ttm_tt
>> *ttm, unsigned long start,
>> unsigned long end)
>> {
>> struct amdgpu_ttm_tt *gtt = (void *)ttm;
>> - struct amdgpu_ttm_gup_task_list *entry;
>> unsigned long size;
>> if (gtt == NULL || !gtt->userptr)
>> @@ -1396,48 +1386,20 @@ bool amdgpu_ttm_tt_affect_userptr(struct
>> ttm_tt *ttm, unsigned long start,
>> if (gtt->userptr > end || gtt->userptr + size <= start)
>> return false;
>> - /* Search the lists of tasks that hold this mapping and see
>> - * if current is one of them. If it is return false.
>> - */
>> - spin_lock(>t->guptasklock);
>> - list_for_each_entry(entry, >t->guptasks, list) {
>> - if (entry->task == current) {
>> - spin_unlock(>t->guptasklock);
>> - return false;
>> - }
>> - }
>> - spin_unlock(>t->guptasklock);
>> -
>> - atomic_inc(>t->mmu_invalidations);
>> -
>> return true;
>> }
>> /**
>> - * amdgpu_ttm_tt_userptr_invalidated - Has the ttm_tt object been
>> invalidated?
>> + * amdgpu_ttm_tt_is_userptr - Have the pages backing by userptr?
>> */
>> -bool amdgpu_ttm_tt_userptr_invalidated(struct ttm_tt *ttm,
>> - int *last_invalidated)
>> -{
>> - struct amdgpu_ttm_tt *gtt = (void *)ttm;
>> - int prev_invalidated = *last_invalidated;
>> -
>> - *last_invalidated = atomic_read(>t->mmu_invalidations);
>> - return prev_invalidated != *last_invalidated;
>> -}
>> -
>> -/**
>> - * amdgpu_ttm_tt_userptr_needs_pages - Have the pages backing this
>> ttm_tt object
>> - * been invalidated since the last time they've been set?
>> - */
>> -bool amdgpu_ttm_tt_userptr_needs_pages(struct ttm_tt *ttm)
>> +bool amdgpu_ttm_tt_is_userptr(struct ttm_tt *ttm)
>> {
>> struct amdgpu_ttm_tt *gtt = (void *)ttm;
>> if (gtt == NULL || !gtt->userptr)
>> return false;
>> - return atomic_read(>t->mmu_invalidations) !=
>> gtt->last_set_pages;
>> + return true;
>> }
>> /**
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> index fe8f276..aeeea77 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> @@ -104,6 +104,7 @@ int amdgpu_ttm_alloc_gart(struct
>> ttm_buffer_object *bo);
>> int amdgpu_ttm_recover_gart(struct ttm_buffer_object *tbo);
>> int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page
>> **pages);
>> +bool amdgpu_ttm_tt_get_user_pages_done(struct ttm_tt *ttm);
>> void amdgpu_ttm_tt_set_user_pages(struct ttm_tt *ttm, struct page
>> **pages);
>> void amdgpu_ttm_tt_mark_user_pages(struct ttm_tt *ttm);
>> int amdgpu_ttm_tt_set_userptr(struct ttm_tt *ttm, uint64_t addr,
>> @@ -114,7 +115,7 @@ bool amdgpu_ttm_tt_affect_userptr(struct ttm_tt
>> *ttm, unsigned long start,
>> unsigned long end);
>> bool amdgpu_ttm_tt_userptr_invalidated(struct ttm_tt *ttm,
>> int *last_invalidated);
>> -bool amdgpu_ttm_tt_userptr_needs_pages(struct ttm_tt *ttm);
>> +bool amdgpu_ttm_tt_is_userptr(struct ttm_tt *ttm);
>> bool amdgpu_ttm_tt_is_readonly(struct ttm_tt *ttm);
>> uint64_t amdgpu_ttm_tt_pde_flags(struct ttm_tt *ttm, struct
>> ttm_mem_reg *mem);
>> uint64_t amdgpu_ttm_tt_pte_flags(struct amdgpu_device *adev, struct
>> ttm_tt *ttm,
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> index 6904d79..fa5bf45 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> @@ -617,7 +617,6 @@ void amdgpu_vm_get_pd_bo(struct amdgpu_vm *vm,
>> entry->priority = 0;
>> entry->tv.bo = &vm->root.base.bo->tbo;
>> entry->tv.shared = true;
>> - entry->user_pages = NULL;
>> list_add(&entry->tv.head, validated);
>> }
>
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