[PATCH v2 14/15] drm/amdgpu: Use mmu_range_notifier instead of hmm_mirror

Yang, Philip Philip.Yang at amd.com
Tue Oct 29 19:22:37 UTC 2019


Hi Jason,

I did quick test after merging amd-staging-drm-next with the 
mmu_notifier branch, which includes this set changes. The test result 
has different failures, app stuck intermittently, GUI no display etc. I 
am understanding the changes and will try to figure out the cause.

Regards,
Philip

On 2019-10-28 4:10 p.m., Jason Gunthorpe wrote:
> From: Jason Gunthorpe <jgg at mellanox.com>
> 
> Convert the collision-retry lock around hmm_range_fault to use the one now
> provided by the mmu_range notifier.
> 
> Although this driver does not seem to use the collision retry lock that
> hmm provides correctly, it can still be converted over to use the
> mmu_range_notifier api instead of hmm_mirror without too much trouble.
> 
> This also deletes another place where a driver is associating additional
> data (struct amdgpu_mn) with a mmu_struct.
> 
> Cc: Alex Deucher <alexander.deucher at amd.com>
> Cc: Christian K├Ânig <christian.koenig at amd.com>
> Cc: David (ChunMing) Zhou <David1.Zhou at amd.com>
> Cc: amd-gfx at lists.freedesktop.org
> Signed-off-by: Jason Gunthorpe <jgg at mellanox.com>
> ---
>   .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  |   4 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c        |  14 +-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c        | 148 ++----------------
>   drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h        |  49 ------
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c       |  76 ++++-----
>   5 files changed, 66 insertions(+), 225 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> index 47700302a08b7f..1bcedb9b477dce 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> @@ -1738,6 +1738,10 @@ static int update_invalid_user_pages(struct amdkfd_process_info *process_info,
>   			return ret;
>   		}
>   
> +		/*
> +		 * FIXME: Cannot ignore the return code, must hold
> +		 * notifier_lock
> +		 */
>   		amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
>   
>   		/* Mark the BO as valid unless it was invalidated
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> index 2e53feed40e230..76771f5f0b60ab 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> @@ -607,8 +607,6 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
>   		e->tv.num_shared = 2;
>   
>   	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);
>   
>   	INIT_LIST_HEAD(&duplicates);
>   	amdgpu_vm_get_pd_bo(&fpriv->vm, &p->validated, &p->vm_pd);
> @@ -1291,11 +1289,11 @@ 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.
> -	 * p->mn is hold until amdgpu_cs_submit is finished and fence is added
> -	 * to BOs.
> +	/* No memory allocation is allowed while holding the notifier lock.
> +	 * The lock is held until amdgpu_cs_submit is finished and fence is
> +	 * added to BOs.
>   	 */
> -	amdgpu_mn_lock(p->mn);
> +	mutex_lock(&p->adev->notifier_lock);
>   
>   	/* If userptr are invalidated after amdgpu_cs_parser_bos(), return
>   	 * -EAGAIN, drmIoctl in libdrm will restart the amdgpu_cs_ioctl.
> @@ -1338,13 +1336,13 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
>   	amdgpu_vm_move_to_lru_tail(p->adev, &fpriv->vm);
>   
>   	ttm_eu_fence_buffer_objects(&p->ticket, &p->validated, p->fence);
> -	amdgpu_mn_unlock(p->mn);
> +	mutex_unlock(&p->adev->notifier_lock);
>   
>   	return 0;
>   
>   error_abort:
>   	drm_sched_job_cleanup(&job->base);
> -	amdgpu_mn_unlock(p->mn);
> +	mutex_unlock(&p->adev->notifier_lock);
>   
>   error_unlock:
>   	amdgpu_job_free(job);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
> index 4ffd7b90f4d907..cb718a064eb491 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
> @@ -50,28 +50,6 @@
>   #include "amdgpu.h"
>   #include "amdgpu_amdkfd.h"
>   
> -/**
> - * amdgpu_mn_lock - take the write side lock for this notifier
> - *
> - * @mn: our notifier
> - */
> -void amdgpu_mn_lock(struct amdgpu_mn *mn)
> -{
> -	if (mn)
> -		down_write(&mn->lock);
> -}
> -
> -/**
> - * amdgpu_mn_unlock - drop the write side lock for this notifier
> - *
> - * @mn: our notifier
> - */
> -void amdgpu_mn_unlock(struct amdgpu_mn *mn)
> -{
> -	if (mn)
> -		up_write(&mn->lock);
> -}
> -
>   /**
>    * amdgpu_mn_invalidate_gfx - callback to notify about mm change
>    *
> @@ -82,12 +60,19 @@ void amdgpu_mn_unlock(struct amdgpu_mn *mn)
>    * potentially dirty.
>    */
>   static bool amdgpu_mn_invalidate_gfx(struct mmu_range_notifier *mrn,
> -				     const struct mmu_notifier_range *range)
> +				     const struct mmu_notifier_range *range,
> +				     unsigned long cur_seq)
>   {
>   	struct amdgpu_bo *bo = container_of(mrn, struct amdgpu_bo, notifier);
>   	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>   	long r;
>   
> +	/*
> +	 * FIXME: Must hold some lock shared with
> +	 * amdgpu_ttm_tt_get_user_pages_done()
> +	 */
> +	mmu_range_set_seq(mrn, cur_seq);
> +
>   	/* FIXME: Is this necessary? */
>   	if (!amdgpu_ttm_tt_affect_userptr(bo->tbo.ttm, range->start,
>   					  range->end))
> @@ -119,11 +104,18 @@ static const struct mmu_range_notifier_ops amdgpu_mn_gfx_ops = {
>    * evicting all user-mode queues of the process.
>    */
>   static bool amdgpu_mn_invalidate_hsa(struct mmu_range_notifier *mrn,
> -				     const struct mmu_notifier_range *range)
> +				     const struct mmu_notifier_range *range,
> +				     unsigned long cur_seq)
>   {
>   	struct amdgpu_bo *bo = container_of(mrn, struct amdgpu_bo, notifier);
>   	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>   
> +	/*
> +	 * FIXME: Must hold some lock shared with
> +	 * amdgpu_ttm_tt_get_user_pages_done()
> +	 */
> +	mmu_range_set_seq(mrn, cur_seq);
> +
>   	/* FIXME: Is this necessary? */
>   	if (!amdgpu_ttm_tt_affect_userptr(bo->tbo.ttm, range->start,
>   					  range->end))
> @@ -143,92 +135,6 @@ 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);
> -
> -	if (!mmu_notifier_range_blockable(update))
> -		return false;
> -
> -	down_read(&amn->lock);
> -	up_read(&amn->lock);
> -	return 0;
> -}
> -
> -/* Low bits of any reasonable mm pointer will be unused due to struct
> - * alignment. Use these bits to make a unique key from the mm pointer
> - * and notifier type.
> - */
> -#define AMDGPU_MN_KEY(mm, type) ((unsigned long)(mm) + (type))
> -
> -static struct hmm_mirror_ops amdgpu_hmm_mirror_ops[] = {
> -	[AMDGPU_MN_TYPE_GFX] = {
> -		.sync_cpu_device_pagetables = amdgpu_mn_sync_pagetables,
> -	},
> -	[AMDGPU_MN_TYPE_HSA] = {
> -		.sync_cpu_device_pagetables = amdgpu_mn_sync_pagetables,
> -	},
> -};
> -
> -/**
> - * amdgpu_mn_get - create HMM mirror context
> - *
> - * @adev: amdgpu device pointer
> - * @type: type of MMU notifier context
> - *
> - * Creates a HMM mirror context for current->mm.
> - */
> -struct amdgpu_mn *amdgpu_mn_get(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;
> -
> -	mutex_lock(&adev->mn_lock);
> -	if (down_write_killable(&mm->mmap_sem)) {
> -		mutex_unlock(&adev->mn_lock);
> -		return ERR_PTR(-EINTR);
> -	}
> -
> -	hash_for_each_possible(adev->mn_hash, amn, node, key)
> -		if (AMDGPU_MN_KEY(amn->mirror.hmm->mmu_notifier.mm,
> -				  amn->type) == key)
> -			goto release_locks;
> -
> -	amn = kzalloc(sizeof(*amn), GFP_KERNEL);
> -	if (!amn) {
> -		amn = ERR_PTR(-ENOMEM);
> -		goto release_locks;
> -	}
> -
> -	amn->adev = adev;
> -	init_rwsem(&amn->lock);
> -	amn->type = type;
> -
> -	amn->mirror.ops = &amdgpu_hmm_mirror_ops[type];
> -	r = hmm_mirror_register(&amn->mirror, mm);
> -	if (r)
> -		goto free_amn;
> -
> -	hash_add(adev->mn_hash, &amn->node, AMDGPU_MN_KEY(mm, type));
> -
> -release_locks:
> -	up_write(&mm->mmap_sem);
> -	mutex_unlock(&adev->mn_lock);
> -
> -	return amn;
> -
> -free_amn:
> -	up_write(&mm->mmap_sem);
> -	mutex_unlock(&adev->mn_lock);
> -	kfree(amn);
> -
> -	return ERR_PTR(r);
> -}
> -
>   /**
>    * amdgpu_mn_register - register a BO for notifier updates
>    *
> @@ -263,25 +169,3 @@ void amdgpu_mn_unregister(struct amdgpu_bo *bo)
>   	mmu_range_notifier_remove(&bo->notifier);
>   	bo->notifier.mm = NULL;
>   }
> -
> -/* 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;
> -	}
> -}
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
> index d73ab2947b22b2..a292238f75ebae 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
> @@ -30,59 +30,10 @@
>   #include <linux/workqueue.h>
>   #include <linux/interval_tree.h>
>   
> -enum amdgpu_mn_type {
> -	AMDGPU_MN_TYPE_GFX,
> -	AMDGPU_MN_TYPE_HSA,
> -};
> -
> -/**
> - * struct amdgpu_mn
> - *
> - * @adev: amdgpu device pointer
> - * @type: type of MMU notifier
> - * @work: destruction work item
> - * @node: hash table node to find structure by adev and mn
> - * @lock: rw semaphore protecting the notifier nodes
> - * @mirror: HMM mirror function support
> - *
> - * Data for each amdgpu device and process address space.
> - */
> -struct amdgpu_mn {
> -	/* constant after initialisation */
> -	struct amdgpu_device	*adev;
> -	enum amdgpu_mn_type	type;
> -
> -	/* only used on destruction */
> -	struct work_struct	work;
> -
> -	/* protected by adev->mn_lock */
> -	struct hlist_node	node;
> -
> -	/* objects protected by lock */
> -	struct rw_semaphore	lock;
> -
> -#ifdef CONFIG_HMM_MIRROR
> -	/* HMM mirror */
> -	struct hmm_mirror	mirror;
> -#endif
> -};
> -
>   #if defined(CONFIG_HMM_MIRROR)
> -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,
> -				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) {}
> -static inline struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
> -					      enum amdgpu_mn_type type)
> -{
> -	return NULL;
> -}
>   static inline int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
>   {
>   	DRM_WARN_ONCE("HMM_MIRROR kernel config option is not enabled, "
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index c0e41f1f0c2365..65d9824b54f2a9 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -773,6 +773,20 @@ struct amdgpu_ttm_tt {
>   #endif
>   };
>   
> +#ifdef CONFIG_DRM_AMDGPU_USERPTR
> +/* 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 */
> +};
> +
>   /**
>    * amdgpu_ttm_tt_get_user_pages - get device accessible pages that back user
>    * memory and start HMM tracking CPU page table update
> @@ -780,29 +794,27 @@ struct amdgpu_ttm_tt {
>    * Calling function must call amdgpu_ttm_tt_userptr_range_done() once and only
>    * once afterwards to stop HMM tracking
>    */
> -#if IS_ENABLED(CONFIG_DRM_AMDGPU_USERPTR)
> -
> -#define MAX_RETRY_HMM_RANGE_FAULT	16
> -
>   int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
>   {
> -	struct hmm_mirror *mirror = bo->mn ? &bo->mn->mirror : NULL;
>   	struct ttm_tt *ttm = bo->tbo.ttm;
>   	struct amdgpu_ttm_tt *gtt = (void *)ttm;
>   	struct mm_struct *mm;
> +	struct hmm_range *range;
>   	unsigned long start = gtt->userptr;
>   	struct vm_area_struct *vma;
> -	struct hmm_range *range;
>   	unsigned long i;
> -	uint64_t *pfns;
>   	int r = 0;
>   
> -	if (unlikely(!mirror)) {
> -		DRM_DEBUG_DRIVER("Failed to get hmm_mirror\n");
> +	mm = bo->notifier.mm;
> +	if (unlikely(!mm)) {
> +		DRM_DEBUG_DRIVER("BO is not registered?\n");
>   		return -EFAULT;
>   	}
>   
> -	mm = mirror->hmm->mmu_notifier.mm;
> +	/* Another get_user_pages is running at the same time?? */
> +	if (WARN_ON(gtt->range))
> +		return -EFAULT;
> +
>   	if (!mmget_not_zero(mm)) /* Happens during process shutdown */
>   		return -ESRCH;
>   
> @@ -811,30 +823,24 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
>   		r = -ENOMEM;
>   		goto out;
>   	}
> +	range->notifier = &bo->notifier;
> +	range->flags = hmm_range_flags;
> +	range->values = hmm_range_values;
> +	range->pfn_shift = PAGE_SHIFT;
> +	range->start = bo->notifier.interval_tree.start;
> +	range->end = bo->notifier.interval_tree.last + 1;
> +	range->default_flags = hmm_range_flags[HMM_PFN_VALID];
> +	if (!amdgpu_ttm_tt_is_readonly(ttm))
> +		range->default_flags |= range->flags[HMM_PFN_WRITE];
>   
> -	pfns = kvmalloc_array(ttm->num_pages, sizeof(*pfns), GFP_KERNEL);
> -	if (unlikely(!pfns)) {
> +	range->pfns = kvmalloc_array(ttm->num_pages, sizeof(*range->pfns),
> +				     GFP_KERNEL);
> +	if (unlikely(!range->pfns)) {
>   		r = -ENOMEM;
>   		goto out_free_ranges;
>   	}
>   
> -	amdgpu_hmm_init_range(range);
> -	range->default_flags = range->flags[HMM_PFN_VALID];
> -	range->default_flags |= amdgpu_ttm_tt_is_readonly(ttm) ?
> -				0 : range->flags[HMM_PFN_WRITE];
> -	range->pfn_flags_mask = 0;
> -	range->pfns = pfns;
> -	range->start = start;
> -	range->end = start + ttm->num_pages * PAGE_SIZE;
> -
> -	hmm_range_register(range, mirror);
> -
> -	/*
> -	 * Just wait for range to be valid, safe to ignore return value as we
> -	 * will use the return value of hmm_range_fault() below under the
> -	 * mmap_sem to ascertain the validity of the range.
> -	 */
> -	hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT);
> +	range->notifier_seq = mmu_range_read_begin(&bo->notifier);
>   
>   	down_read(&mm->mmap_sem);
>   	vma = find_vma(mm, start);
> @@ -855,10 +861,10 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
>   		goto out_free_pfns;
>   
>   	for (i = 0; i < ttm->num_pages; i++) {
> -		pages[i] = hmm_device_entry_to_page(range, pfns[i]);
> +		pages[i] = hmm_device_entry_to_page(range, range->pfns[i]);
>   		if (unlikely(!pages[i])) {
>   			pr_err("Page fault failed for pfn[%lu] = 0x%llx\n",
> -			       i, pfns[i]);
> +			       i, range->pfns[i]);
>   			r = -ENOMEM;
>   
>   			goto out_free_pfns;
> @@ -873,8 +879,7 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
>   out_unlock:
>   	up_read(&mm->mmap_sem);
>   out_free_pfns:
> -	hmm_range_unregister(range);
> -	kvfree(pfns);
> +	kvfree(range->pfns);
>   out_free_ranges:
>   	kfree(range);
>   out:
> @@ -903,9 +908,8 @@ bool amdgpu_ttm_tt_get_user_pages_done(struct ttm_tt *ttm)
>   		"No user pages to check\n");
>   
>   	if (gtt->range) {
> -		r = hmm_range_valid(gtt->range);
> -		hmm_range_unregister(gtt->range);
> -
> +		r = mmu_range_read_retry(gtt->range->notifier,
> +					 gtt->range->notifier_seq);
>   		kvfree(gtt->range->pfns);
>   		kfree(gtt->range);
>   		gtt->range = NULL;
> 


More information about the dri-devel mailing list