回复: [RFC PATCH v2] drm/amdgpu: Remove kfd eviction fence before release bo
Pan, Xinhui
Xinhui.Pan at amd.com
Fri Feb 7 13:50:52 UTC 2020
[AMD Official Use Only - Internal Distribution Only]
________________________________________
发件人: Koenig, Christian <Christian.Koenig at amd.com>
发送时间: 2020年2月7日 21:46
收件人: Pan, Xinhui; amd-gfx at lists.freedesktop.org
抄送: Kuehling, Felix; Deucher, Alexander
主题: Re: [RFC PATCH v2] drm/amdgpu: Remove kfd eviction fence before release bo
Am 07.02.20 um 14:42 schrieb Pan, Xinhui:
> No need to trigger eviction as the memory mapping will not be used anymore.
>
> All pt/pd bos share same resv, hence the same shared eviction fence. Everytime page table is freed, the fence will be signled and that cuases kfd unexcepted evictions.
>
> Signed-off-by: xinhui pab <xinhui.pan at example.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 1 +
> .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 78 ++++++++++++++++++-
> drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 10 ++-
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 5 +-
> drivers/gpu/drm/ttm/ttm_bo.c | 38 +++++----
> 5 files changed, 111 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
> index 47b0f2957d1f..265b1ed7264c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
> @@ -96,6 +96,7 @@ struct amdgpu_amdkfd_fence *amdgpu_amdkfd_fence_create(u64 context,
> struct mm_struct *mm);
> bool amdkfd_fence_check_mm(struct dma_fence *f, struct mm_struct *mm);
> struct amdgpu_amdkfd_fence *to_amdgpu_amdkfd_fence(struct dma_fence *f);
> +int amdgpu_amdkfd_remove_fence_on_pt_pd_bos(struct amdgpu_bo *bo);
>
> struct amdkfd_process_info {
> /* List head of all VMs that belong to a KFD process */
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> index ef721cb65868..11315095c29b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> @@ -223,7 +223,7 @@ void amdgpu_amdkfd_unreserve_memory_limit(struct amdgpu_bo *bo)
> static int amdgpu_amdkfd_remove_eviction_fence(struct amdgpu_bo *bo,
> struct amdgpu_amdkfd_fence *ef)
> {
> - struct dma_resv *resv = bo->tbo.base.resv;
> + struct dma_resv *resv = &bo->tbo.base._resv;
That won't work either and probably break a bunch of other cases.
[xh] kfd bos which are allocated explicitly use _resv AFAIK.
only pt/pd bos share the root._resv
Christian.
> struct dma_resv_list *old, *new;
> unsigned int i, j, k;
>
> @@ -276,6 +276,78 @@ static int amdgpu_amdkfd_remove_eviction_fence(struct amdgpu_bo *bo,
> return 0;
> }
>
> +int amdgpu_amdkfd_remove_fence_on_pt_pd_bos(struct amdgpu_bo *bo)
> +{
> + struct amdgpu_vm_bo_base *vm_bo = bo->vm_bo;
> + struct amdgpu_vm *vm;
> + struct amdkfd_process_info *info;
> + struct amdgpu_amdkfd_fence *ef;
> + struct amdgpu_bo *parent;
> + int locked;
> + int ret;
> + struct ttm_bo_global *glob = &ttm_bo_glob;
> +
> + if (vm_bo == NULL)
> + return 0;
> +
> + /* Page table bo has a reference of the parent bo.
> + * BO itself can't guarntee the vm it points to is alive.
> + * for example, VM is going to free page tables, and the pt/pd bo might be
> + * freed by a workqueue. In that case, the vm might be freed already,
> + * leaving the bo->vm_bo points to vm.root.
> + *
> + * so to avoid that, when kfd free its vms,
> + * 1) set vm->process_info to NULL if this is the last vm.
> + * 2) set root_bo->vm_bo to NULL.
> + *
> + * but there are still races, just like
> + * cpu 1 cpu 2
> + * !vm_bo
> + * ->info = NULL
> + * free(info)
> + * ->vm_bo = NULL
> + * free (vm)
> + * info = vm->info //invalid vm
> + *
> + * So to avoid the race, use ttm_bo_glob lru_lock.
> + * generally speaking, adding a new lock is accceptable.
> + * But reusing this lock is simple.
> + */
> + parent = bo;
> + while (parent->parent)
> + parent = parent->parent;
> +
> + spin_lock(&glob->lru_lock);
> + vm_bo = parent->vm_bo;
> + if (!vm_bo) {
> + spin_unlock(&glob->lru_lock);
> + return 0;
> + }
> +
> + vm = vm_bo->vm;
> + if (!vm) {
> + spin_unlock(&glob->lru_lock);
> + return 0;
> + }
> +
> + info = vm->process_info;
> + if (!info || !info->eviction_fence) {
> + spin_unlock(&glob->lru_lock);
> + return 0;
> + }
> +
> + ef = container_of(dma_fence_get(&info->eviction_fence->base),
> + struct amdgpu_amdkfd_fence, base);
> + spin_unlock(&glob->lru_lock);
> +
> + locked = dma_resv_trylock(&bo->tbo.base._resv);
> + ret = amdgpu_amdkfd_remove_eviction_fence(bo, ef);
> + dma_fence_put(&ef->base);
> + if (locked)
> + dma_resv_unlock(&bo->tbo.base._resv);
> + return ret;
> +}
> +
> static int amdgpu_amdkfd_bo_validate(struct amdgpu_bo *bo, uint32_t domain,
> bool wait)
> {
> @@ -1030,6 +1102,7 @@ void amdgpu_amdkfd_gpuvm_destroy_cb(struct amdgpu_device *adev,
> {
> struct amdkfd_process_info *process_info = vm->process_info;
> struct amdgpu_bo *pd = vm->root.base.bo;
> + struct ttm_bo_global *glob = &ttm_bo_glob;
>
> if (!process_info)
> return;
> @@ -1051,6 +1124,9 @@ void amdgpu_amdkfd_gpuvm_destroy_cb(struct amdgpu_device *adev,
> WARN_ON(!list_empty(&process_info->userptr_valid_list));
> WARN_ON(!list_empty(&process_info->userptr_inval_list));
>
> + spin_lock(&glob->lru_lock);
> + vm->process_info = NULL;
> + spin_unlock(&glob->lru_lock);
> dma_fence_put(&process_info->eviction_fence->base);
> cancel_delayed_work_sync(&process_info->restore_userptr_work);
> put_pid(process_info->pid);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> index 6f60a581e3ba..6ad12298fa84 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> @@ -1307,19 +1307,23 @@ void amdgpu_bo_release_notify(struct ttm_buffer_object *bo)
> if (abo->kfd_bo)
> amdgpu_amdkfd_unreserve_memory_limit(abo);
>
> + amdgpu_amdkfd_remove_fence_on_pt_pd_bos(abo);
> + abo->vm_bo = NULL;
> +
> if (bo->mem.mem_type != TTM_PL_VRAM || !bo->mem.mm_node ||
> !(abo->flags & AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE))
> return;
>
> - dma_resv_lock(bo->base.resv, NULL);
> + /* Only kfd bo wipe vram on release. The resv is &_resv. */
> + dma_resv_lock(&bo->base._resv, NULL);
>
> - r = amdgpu_fill_buffer(abo, AMDGPU_POISON, bo->base.resv, &fence);
> + r = amdgpu_fill_buffer(abo, AMDGPU_POISON, &bo->base._resv, &fence);
> if (!WARN_ON(r)) {
> amdgpu_bo_fence(abo, fence, false);
> dma_fence_put(fence);
> }
>
> - dma_resv_unlock(bo->base.resv);
> + dma_resv_unlock(&bo->base._resv);
> }
>
> /**
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index cc56eaba1911..2b96447e30e5 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -945,7 +945,6 @@ static int amdgpu_vm_alloc_pts(struct amdgpu_device *adev,
> static void amdgpu_vm_free_table(struct amdgpu_vm_pt *entry)
> {
> if (entry->base.bo) {
> - entry->base.bo->vm_bo = NULL;
> list_del(&entry->base.vm_status);
> amdgpu_bo_unref(&entry->base.bo->shadow);
> amdgpu_bo_unref(&entry->base.bo);
> @@ -3074,6 +3073,7 @@ void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
> struct amdgpu_bo_va_mapping *mapping, *tmp;
> bool prt_fini_needed = !!adev->gmc.gmc_funcs->set_prt;
> struct amdgpu_bo *root;
> + struct ttm_bo_global *glob = &ttm_bo_glob;
> int i;
>
> amdgpu_amdkfd_gpuvm_destroy_cb(adev, vm);
> @@ -3105,6 +3105,9 @@ void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
> }
>
> amdgpu_vm_free_pts(adev, vm, NULL);
> + spin_lock(&glob->lru_lock);
> + root->vm_bo = NULL;
> + spin_unlock(&glob->lru_lock);
> amdgpu_bo_unreserve(root);
> amdgpu_bo_unref(&root);
> WARN_ON(vm->root.base.bo);
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 1494aebb8128..706cd60eb9e0 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -429,8 +429,8 @@ static int ttm_bo_individualize_resv(struct ttm_buffer_object *bo)
> BUG_ON(!dma_resv_trylock(&bo->base._resv));
>
> r = dma_resv_copy_fences(&bo->base._resv, bo->base.resv);
> - if (r)
> - dma_resv_unlock(&bo->base._resv);
> +
> + dma_resv_unlock(&bo->base._resv);
>
> return r;
> }
> @@ -455,23 +455,19 @@ static void ttm_bo_flush_all_fences(struct ttm_buffer_object *bo)
> }
> }
>
> -static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo)
> +static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo, bool enqueue)
> {
> struct ttm_bo_device *bdev = bo->bdev;
> int ret;
>
> - ret = ttm_bo_individualize_resv(bo);
> - if (ret) {
> - /* Last resort, if we fail to allocate memory for the
> - * fences block for the BO to become idle
> - */
> - dma_resv_wait_timeout_rcu(bo->base.resv, true, false,
> - 30 * HZ);
> - spin_lock(&ttm_bo_glob.lru_lock);
> - goto error;
> - }
> -
> spin_lock(&ttm_bo_glob.lru_lock);
> +
> + if (enqueue)
> + goto queue;
> +
> + if (bo->base.resv != &bo->base._resv)
> + BUG_ON(!dma_resv_trylock(&bo->base._resv));
> +
> ret = dma_resv_trylock(bo->base.resv) ? 0 : -EBUSY;
> if (!ret) {
> if (dma_resv_test_signaled_rcu(&bo->base._resv, true)) {
> @@ -504,7 +500,7 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo)
> dma_resv_unlock(&bo->base._resv);
> }
>
> -error:
> +queue:
> kref_get(&bo->list_kref);
> list_add_tail(&bo->ddestroy, &bdev->ddestroy);
> spin_unlock(&ttm_bo_glob.lru_lock);
> @@ -655,6 +651,16 @@ static void ttm_bo_release(struct kref *kref)
> container_of(kref, struct ttm_buffer_object, kref);
> struct ttm_bo_device *bdev = bo->bdev;
> struct ttm_mem_type_manager *man = &bdev->man[bo->mem.mem_type];
> + int ret;
> +
> + ret = ttm_bo_individualize_resv(bo);
> + if (ret) {
> + /* Last resort, if we fail to allocate memory for the
> + * fences block for the BO to become idle
> + */
> + dma_resv_wait_timeout_rcu(bo->base.resv, true, false,
> + 30 * HZ);
> + }
>
> if (bo->bdev->driver->release_notify)
> bo->bdev->driver->release_notify(bo);
> @@ -663,7 +669,7 @@ static void ttm_bo_release(struct kref *kref)
> ttm_mem_io_lock(man, false);
> ttm_mem_io_free_vm(bo);
> ttm_mem_io_unlock(man);
> - ttm_bo_cleanup_refs_or_queue(bo);
> + ttm_bo_cleanup_refs_or_queue(bo, !!ret);
> kref_put(&bo->list_kref, ttm_bo_release_list);
> }
>
More information about the amd-gfx
mailing list