[PATCH 2/2] drm/amdkfd: Remove svm_bo eviction fence
Philip Yang <[email protected]> Mon, 27 Jul 2026 16:16:52 -0400
| Newsgroups | org.freedesktop.lists.amd-gfx |
|---|---|
| Message-ID | <[email protected]> |
SVM BOs are now migrated back to system memory synchronously from the TTM eviction path (svm_range_evict_svm_bo), so the per-svm_bo eviction fence is no longer used. Remove the eviction fence from svm_range_bo, drop the amdgpu_amdkfd_fence->svm_bo back pointer and the amdgpu_amdkfd_evict_svm_bo() helper, and stop special-casing svm_bo fences in the KFD fence enable_signaling and check_mm paths. Embed struct amdgpu_bo directly in svm_range_bo with a dedicated svm_range_bo_destroy() callback, and keep the owning mm via mmgrab()/mmdrop() instead of through the fence. Signed-off-by: Philip Yang <[email protected]> Reviewed-by: Felix Kuehling <[email protected]> --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c | 21 ---- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 3 - .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c | 15 +-- .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 4 +- drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 4 +- drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 6 +- drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 4 +- drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 109 +++++++----------- drivers/gpu/drm/amd/amdkfd/kfd_svm.h | 13 ++- 9 files changed, 64 insertions(+), 115 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c index be764b6802b5..816d8817f0b2 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c @@ -973,24 +973,3 @@ int amdgpu_amdkfd_reset_mes_queue(struct amdgpu_device *adev, return kgd2kfd_reset_mes_queue(adev->kfd.dev, node_id, queue_type, pipe, queue, db); } - -int amdgpu_amdkfd_evict_svm_bo(struct amdgpu_bo *bo) -{ - struct dma_resv_iter cursor; - struct dma_fence *fence; - int r = 0; - - dma_resv_iter_begin(&cursor, bo->tbo.base.resv, DMA_RESV_USAGE_BOOKKEEP); - dma_resv_for_each_fence_unlocked(&cursor, fence) { - struct amdgpu_amdkfd_fence *f = to_amdgpu_amdkfd_fence(fence); - - if (f && f->svm_bo) { - r = svm_range_evict_svm_bo(f->svm_bo); - if (r) - break; - } - } - dma_resv_iter_end(&cursor); - - return r; -} diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h index b4840ee36f2b..1b7dc0d3963b 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h @@ -99,7 +99,6 @@ struct amdgpu_amdkfd_fence { struct mm_struct *mm; spinlock_t lock; char timeline_name[TASK_COMM_LEN]; - struct svm_range_bo *svm_bo; uint16_t context_id; }; @@ -194,7 +193,6 @@ int amdgpu_queue_mask_bit_to_set_resource_bit(struct amdgpu_device *adev, struct amdgpu_amdkfd_fence *amdgpu_amdkfd_fence_create(u64 context, struct mm_struct *mm, - struct svm_range_bo *svm_bo, u16 context_id); int amdgpu_amdkfd_drm_client_create(struct amdgpu_device *adev); @@ -286,7 +284,6 @@ int amdgpu_amdkfd_reset_mes_queue(struct amdgpu_device *adev, int queue_type, int pipe, int queue, unsigned int db); -int amdgpu_amdkfd_evict_svm_bo(struct amdgpu_bo *bo); /* Read user wptr from a specified user address space with page fault * disabled. The memory must be pinned and mapped to the hardware when diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c index 553d26c2744e..9b10d015671c 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c @@ -62,7 +62,6 @@ static atomic_t fence_seq = ATOMIC_INIT(0); struct amdgpu_amdkfd_fence *amdgpu_amdkfd_fence_create(u64 context, struct mm_struct *mm, - struct svm_range_bo *svm_bo, u16 context_id) { struct amdgpu_amdkfd_fence *fence; @@ -76,7 +75,6 @@ struct amdgpu_amdkfd_fence *amdgpu_amdkfd_fence_create(u64 context, fence->mm = mm; get_task_comm(fence->timeline_name, current); spin_lock_init(&fence->lock); - fence->svm_bo = svm_bo; fence->context_id = context_id; dma_fence_init(&fence->base, &amdkfd_fence_ops, &fence->lock, context, atomic_inc_return(&fence_seq)); @@ -128,14 +126,8 @@ static bool amdkfd_fence_enable_signaling(struct dma_fence *f) if (dma_fence_is_signaled(f)) return true; - /* if fence->svm_bo is NULL, means this fence is created through - * init_kfd_vm() or amdgpu_amdkfd_gpuvm_restore_process_bos(). - * Therefore, this fence is amdgpu_amdkfd_fence->eviction_fence. - */ - if (!fence->svm_bo) { - if (!kgd2kfd_schedule_evict_and_restore_process(fence->mm, fence->context_id, f)) - return true; - } + if (!kgd2kfd_schedule_evict_and_restore_process(fence->mm, fence->context_id, f)) + return true; return false; } @@ -169,7 +161,6 @@ static void amdkfd_fence_release(struct dma_fence *f) * * Check if @mm is same as that of the fence @f, if same return TRUE else * return FALSE. - * For svm bo, which support vram overcommitment, always return FALSE. */ bool amdkfd_fence_check_mm(struct dma_fence *f, struct mm_struct *mm) { @@ -177,7 +168,7 @@ bool amdkfd_fence_check_mm(struct dma_fence *f, struct mm_struct *mm) if (!fence) return false; - else if (fence->mm == mm && !fence->svm_bo) + else if (fence->mm == mm) return true; return false; diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 451d7f7ef5c1..1e71829e0fc6 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -1423,7 +1423,7 @@ static int init_kfd_vm(struct amdgpu_vm *vm, void **process_info, info->eviction_fence = amdgpu_amdkfd_fence_create(dma_fence_context_alloc(1), current->mm, - NULL, process->context_id); + process->context_id); if (!info->eviction_fence) { pr_err("Failed to create eviction fence\n"); ret = -ENOMEM; @@ -3093,7 +3093,7 @@ int amdgpu_amdkfd_gpuvm_restore_process_bos(void *info, struct dma_fence __rcu * amdgpu_amdkfd_fence_create( process_info->eviction_fence->base.context, process_info->eviction_fence->mm, - NULL, process_info->context_id); + process_info->context_id); if (!new_fence) { pr_err("Failed to create eviction fence\n"); diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c index d4a9d5e8fb42..5d9d137209b6 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c @@ -43,6 +43,7 @@ #include "amdgpu_vram_mgr.h" #include "amdgpu_vm.h" #include "amdgpu_dma_buf.h" +#include "kfd_svm.h" /** * DOC: amdgpu_object @@ -93,7 +94,8 @@ static void amdgpu_bo_user_destroy(struct ttm_buffer_object *tbo) bool amdgpu_bo_is_amdgpu_bo(struct ttm_buffer_object *bo) { if (bo->destroy == &amdgpu_bo_destroy || - bo->destroy == &amdgpu_bo_user_destroy) + bo->destroy == &amdgpu_bo_user_destroy || + bo->destroy == &svm_range_bo_destroy) return true; return false; diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index 746290216aae..0e7e586b217a 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -60,6 +60,7 @@ #include "amdgpu_atomfirmware.h" #include "amdgpu_res_cursor.h" #include "bif/bif_4_1_d.h" +#include "kfd_svm.h" MODULE_IMPORT_NS("DMA_BUF"); @@ -1499,7 +1500,8 @@ static bool amdgpu_ttm_bo_eviction_valuable(struct ttm_buffer_object *bo, return true; abo = ttm_to_amdgpu_bo(bo); - if (abo->flags & AMDGPU_GEM_CREATE_DISCARDABLE) { + if ((abo->flags & AMDGPU_GEM_CREATE_DISCARDABLE) && + bo->destroy == &svm_range_bo_destroy) { /* * SVM BOs are migrated to system memory synchronously in this * TTM eviction context. The migration needs the owning @@ -1509,7 +1511,7 @@ static bool amdgpu_ttm_bo_eviction_valuable(struct ttm_buffer_object *bo, * if the eviction fails for any reason, we return false so TTM * skips this BO instead of risking a deadlock. */ - if (amdgpu_amdkfd_evict_svm_bo(abo) < 0) + if (svm_range_evict_svm_bo(abo) < 0) return false; } diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c index ed3649a81332..f5af1dd3b70e 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c @@ -954,12 +954,12 @@ static vm_fault_t svm_migrate_to_ram(struct vm_fault *vmf) pr_debug("failed get device page at addr 0x%lx\n", addr); return VM_FAULT_SIGBUS; } - if (!mmget_not_zero(svm_bo->eviction_fence->mm)) { + if (!mmget_not_zero(svm_bo->mm)) { pr_debug("addr 0x%lx of process mm is destroyed\n", addr); return VM_FAULT_SIGBUS; } - mm = svm_bo->eviction_fence->mm; + mm = svm_bo->mm; if (mm != vmf->vma->vm_mm) pr_debug("addr 0x%lx is COW mapping in child process\n", addr); diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c index 4c6700c6e88d..18abef8918ce 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -390,8 +390,10 @@ static bool svm_bo_ref_unless_zero(struct svm_range_bo *svm_bo) static void svm_range_bo_release(struct kref *kref) { struct svm_range_bo *svm_bo; + struct amdgpu_bo *bo; svm_bo = container_of(kref, struct svm_range_bo, kref); + bo = &svm_bo->bo; pr_debug("svm_bo 0x%p\n", svm_bo); spin_lock(&svm_bo->list_lock); @@ -417,12 +419,12 @@ static void svm_range_bo_release(struct kref *kref) } spin_unlock(&svm_bo->list_lock); - if (mmget_not_zero(svm_bo->eviction_fence->mm)) { + if (mmget_not_zero(svm_bo->mm)) { struct kfd_process_device *pdd; struct kfd_process *p; struct mm_struct *mm; - mm = svm_bo->eviction_fence->mm; + mm = svm_bo->mm; /* * The forked child process takes svm_bo device pages ref, svm_bo could be * released after parent process is gone. @@ -431,18 +433,13 @@ static void svm_range_bo_release(struct kref *kref) if (p) { pdd = kfd_get_process_device_data(svm_bo->node, p); if (pdd) - atomic64_sub(amdgpu_bo_size(svm_bo->bo), &pdd->vram_usage); + atomic64_sub(amdgpu_bo_size(bo), &pdd->vram_usage); kfd_unref_process(p); } mmput(mm); } - if (!dma_fence_is_signaled(&svm_bo->eviction_fence->base)) - /* We're not in the eviction worker. Signal the fence. */ - dma_fence_signal(&svm_bo->eviction_fence->base); - dma_fence_put(&svm_bo->eviction_fence->base); - amdgpu_bo_unref(&svm_bo->bo); - kfree(svm_bo); + amdgpu_bo_unref(&bo); } static void svm_range_bo_wq_release(struct work_struct *work) @@ -504,20 +501,11 @@ svm_range_validate_svm_bo(struct kfd_node *node, struct svm_range *prange) return false; } if (READ_ONCE(prange->svm_bo->evicting)) { - struct dma_fence *f; - struct svm_range_bo *svm_bo; /* The BO is getting evicted, * we need to get a new one */ mutex_unlock(&prange->lock); - svm_bo = prange->svm_bo; - f = dma_fence_get(&svm_bo->eviction_fence->base); svm_range_bo_unref(prange->svm_bo); - /* wait for the fence to avoid long spin-loop - * at list_empty_careful - */ - dma_fence_wait(f, false); - dma_fence_put(f); } else { /* The BO was still around and we got * a new reference to it @@ -526,7 +514,7 @@ svm_range_validate_svm_bo(struct kfd_node *node, struct svm_range *prange) pr_debug("reuse old bo svms 0x%p [0x%lx 0x%lx]\n", prange->svms, prange->start, prange->last); - prange->ttm_res = prange->svm_bo->bo->tbo.resource; + prange->ttm_res = prange->svm_bo->bo.tbo.resource; return true; } @@ -545,19 +533,22 @@ svm_range_validate_svm_bo(struct kfd_node *node, struct svm_range *prange) return false; } -static struct svm_range_bo *svm_range_bo_new(void) -{ - struct svm_range_bo *svm_bo; +#define to_svm_range_bo(bo) container_of((bo), struct svm_range_bo, bo) - svm_bo = kzalloc_obj(*svm_bo); - if (!svm_bo) - return NULL; - - kref_init(&svm_bo->kref); - INIT_LIST_HEAD(&svm_bo->range_list); - spin_lock_init(&svm_bo->list_lock); +void svm_range_bo_destroy(struct ttm_buffer_object *tbo) +{ + struct amdgpu_bo *bo = ttm_to_amdgpu_bo(tbo); + struct svm_range_bo *svm_bo = to_svm_range_bo(bo); - return svm_bo; + drm_gem_object_release(&bo->tbo.base); + /* + * svm_bo->mm is only set once the BO is fully created. If + * ttm_bo_init_reserved() fails (e.g. no VRAM could be evicted), it + * calls this destroy callback with mm still NULL, so guard the drop. + */ + if (svm_bo->mm) + mmdrop(svm_bo->mm); + kvfree(svm_bo); } int @@ -567,7 +558,6 @@ svm_range_vram_node_new(struct kfd_node *node, struct svm_range *prange, struct kfd_process_device *pdd; struct amdgpu_bo_param bp; struct svm_range_bo *svm_bo; - struct amdgpu_bo_user *ubo; struct amdgpu_bo *bo; struct kfd_process *p; struct mm_struct *mm; @@ -581,26 +571,16 @@ svm_range_vram_node_new(struct kfd_node *node, struct svm_range *prange, if (svm_range_validate_svm_bo(node, prange)) return 0; - svm_bo = svm_range_bo_new(); - if (!svm_bo) { - pr_debug("failed to alloc svm bo\n"); - return -ENOMEM; - } mm = get_task_mm(p->lead_thread); if (!mm) { pr_debug("failed to get mm\n"); - kfree(svm_bo); return -ESRCH; } - svm_bo->node = node; - svm_bo->eviction_fence = - amdgpu_amdkfd_fence_create(dma_fence_context_alloc(1), - mm, - svm_bo, p->context_id); - mmput(mm); - svm_bo->evicting = 0; + memset(&bp, 0, sizeof(bp)); bp.size = prange->npages * PAGE_SIZE; + bp.bo_ptr_size = sizeof(struct svm_range_bo); + bp.destroy = svm_range_bo_destroy; bp.byte_align = PAGE_SIZE; bp.domain = AMDGPU_GEM_DOMAIN_VRAM; bp.flags = AMDGPU_GEM_CREATE_NO_CPU_ACCESS; @@ -611,12 +591,23 @@ svm_range_vram_node_new(struct kfd_node *node, struct svm_range *prange, if (node->xcp) bp.xcp_id_plus1 = node->xcp->id + 1; - r = amdgpu_bo_create_user(node->adev, &bp, &ubo); + r = amdgpu_bo_create(node->adev, &bp, &bo); if (r) { pr_debug("failed %d to create bo\n", r); + mmput(mm); goto create_bo_failed; } - bo = &ubo->bo; + + svm_bo = to_svm_range_bo(bo); + svm_bo->evicting = 0; + kref_init(&svm_bo->kref); + INIT_LIST_HEAD(&svm_bo->range_list); + spin_lock_init(&svm_bo->list_lock); + + svm_bo->node = node; + svm_bo->mm = mm; + mmgrab(svm_bo->mm); + mmput(mm); pr_debug("alloc bo at offset 0x%lx size 0x%lx on partition %d\n", bo->tbo.resource->start << PAGE_SHIFT, bp.size, @@ -637,16 +628,8 @@ svm_range_vram_node_new(struct kfd_node *node, struct svm_range *prange, } } - r = dma_resv_reserve_fences(bo->tbo.base.resv, TTM_NUM_MOVE_FENCES); - if (r) { - amdgpu_bo_unreserve(bo); - goto reserve_bo_failed; - } - amdgpu_bo_fence(bo, &svm_bo->eviction_fence->base, true); - amdgpu_bo_unreserve(bo); - svm_bo->bo = bo; prange->svm_bo = svm_bo; prange->ttm_res = bo->tbo.resource; prange->offset = 0; @@ -664,9 +647,6 @@ svm_range_vram_node_new(struct kfd_node *node, struct svm_range *prange, reserve_bo_failed: amdgpu_bo_unref(&bo); create_bo_failed: - dma_fence_put(&svm_bo->eviction_fence->base); - kfree(svm_bo); - prange->ttm_res = NULL; return r; } @@ -3640,19 +3620,20 @@ svm_range_trigger_migration(struct mm_struct *mm, struct svm_range *prange, return 0; } -int svm_range_evict_svm_bo(struct svm_range_bo *svm_bo) +int svm_range_evict_svm_bo(struct amdgpu_bo *bo) { + struct svm_range_bo *svm_bo = to_svm_range_bo(bo); struct mm_struct *mm; int r = 0; if (!svm_bo_ref_unless_zero(svm_bo)) return 0; - if (!mmget_not_zero(svm_bo->eviction_fence->mm)) { + if (!mmget_not_zero(svm_bo->mm)) { svm_range_bo_unref(svm_bo); return 0; } - mm = svm_bo->eviction_fence->mm; + mm = svm_bo->mm; /* * Called with the BO reserved; lock order is mmap_lock -> BO @@ -3721,14 +3702,6 @@ int svm_range_evict_svm_bo(struct svm_range_bo *svm_bo) /* Defer mmput: exit_mmap() must not run under the BO reservation. */ mmput_async(mm); - /* - * Only signal the eviction fence once the ranges have been processed. - * On -EBUSY we bailed out without migrating; leave the BO in VRAM and - * let TTM retry later. - */ - if (r != -EBUSY) - dma_fence_signal(&svm_bo->eviction_fence->base); - /* This is the last reference to svm_bo, after svm_range_vram_node_free * has been called in svm_migrate_vram_to_ram */ diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h index 4232c47422e6..284c4cd5aa0f 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h @@ -39,11 +39,11 @@ ((adev)->hive ? (void *)(adev)->hive : (void *)(adev)) struct svm_range_bo { - struct amdgpu_bo *bo; + struct amdgpu_bo bo; struct kref kref; struct list_head range_list; /* all svm ranges shared this bo */ spinlock_t list_lock; - struct amdgpu_amdkfd_fence *eviction_fence; + struct mm_struct *mm; uint32_t evicting; struct work_struct release_work; struct kfd_node *node; @@ -168,13 +168,14 @@ struct svm_range *svm_range_from_addr(struct svm_range_list *svms, struct svm_range **parent); struct kfd_node *svm_range_get_node_by_id(struct svm_range *prange, uint32_t gpu_id); +void svm_range_bo_destroy(struct ttm_buffer_object *tbo); int svm_range_vram_node_new(struct kfd_node *node, struct svm_range *prange, bool clear); void svm_range_vram_node_free(struct svm_range *prange); int svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid, uint32_t vmid, uint32_t node_id, uint64_t addr, uint64_t ts, bool write_fault); -int svm_range_evict_svm_bo(struct svm_range_bo *svm_bo); +int svm_range_evict_svm_bo(struct amdgpu_bo *bo); void svm_range_add_list_work(struct svm_range_list *svms, struct svm_range *prange, struct mm_struct *mm, @@ -229,7 +230,11 @@ static inline int svm_range_restore_pages(struct amdgpu_device *adev, return -EFAULT; } -static inline int svm_range_evict_svm_bo(struct svm_range_bo *svm_bo) +static inline void svm_range_bo_destroy(struct ttm_buffer_object *tbo) +{ +} + +static inline int svm_range_evict_svm_bo(struct amdgpu_bo *bo) { return 0; } -- 2.50.1