From 1ec39923ef24f55eaa12cbdbdd9bb7e4ba29f6a7 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Christian=20K=C3=B6nig?= Date: Mon, 11 Nov 2019 14:42:13 +0100 Subject: [PATCH] drm/ttm: rework BO delayed delete. v2 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This patch reworks the whole delayed deletion of BOs which aren't idle. Instead of having two counters for the BO structure we resurrect the BO when we find that a deleted BO is not idle yet. This has many advantages, especially that we don't need to increment/decrement the BOs reference counter any more when it moves on the LRUs. v2: remove duplicate ttm_tt_destroy, fix holde lock for LRU move Signed-off-by: Christian König Reviewed-by: xinhui pan Link: https://patchwork.freedesktop.org/patch/352912/ --- drivers/gpu/drm/ttm/ttm_bo.c | 217 +++++++++++++++++--------------------- drivers/gpu/drm/ttm/ttm_bo_util.c | 1 - include/drm/ttm/ttm_bo_api.h | 11 +- 3 files changed, 97 insertions(+), 132 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index e12fc2c..28fd91c 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -145,26 +145,6 @@ static inline uint32_t ttm_bo_type_flags(unsigned type) return 1 << (type); } -static void ttm_bo_release_list(struct kref *list_kref) -{ - struct ttm_buffer_object *bo = - container_of(list_kref, struct ttm_buffer_object, list_kref); - size_t acc_size = bo->acc_size; - - BUG_ON(kref_read(&bo->list_kref)); - BUG_ON(kref_read(&bo->kref)); - BUG_ON(bo->mem.mm_node != NULL); - BUG_ON(!list_empty(&bo->lru)); - BUG_ON(!list_empty(&bo->ddestroy)); - ttm_tt_destroy(bo->ttm); - atomic_dec(&ttm_bo_glob.bo_count); - dma_fence_put(bo->moving); - if (!ttm_bo_uses_embedded_gem_object(bo)) - dma_resv_fini(&bo->base._resv); - bo->destroy(bo); - ttm_mem_global_free(&ttm_mem_glob, acc_size); -} - static void ttm_bo_add_mem_to_lru(struct ttm_buffer_object *bo, struct ttm_mem_reg *mem) { @@ -181,21 +161,14 @@ static void ttm_bo_add_mem_to_lru(struct ttm_buffer_object *bo, man = &bdev->man[mem->mem_type]; list_add_tail(&bo->lru, &man->lru[bo->priority]); - kref_get(&bo->list_kref); if (!(man->flags & TTM_MEMTYPE_FLAG_FIXED) && bo->ttm && !(bo->ttm->page_flags & (TTM_PAGE_FLAG_SG | TTM_PAGE_FLAG_SWAPPED))) { list_add_tail(&bo->swap, &ttm_bo_glob.swap_lru[bo->priority]); - kref_get(&bo->list_kref); } } -static void ttm_bo_ref_bug(struct kref *list_kref) -{ - BUG(); -} - static void ttm_bo_del_from_lru(struct ttm_buffer_object *bo) { struct ttm_bo_device *bdev = bo->bdev; @@ -203,12 +176,10 @@ static void ttm_bo_del_from_lru(struct ttm_buffer_object *bo) if (!list_empty(&bo->swap)) { list_del_init(&bo->swap); - kref_put(&bo->list_kref, ttm_bo_ref_bug); notify = true; } if (!list_empty(&bo->lru)) { list_del_init(&bo->lru); - kref_put(&bo->list_kref, ttm_bo_ref_bug); notify = true; } @@ -421,8 +392,7 @@ 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; } @@ -449,68 +419,10 @@ static void ttm_bo_flush_all_fences(struct ttm_buffer_object *bo) rcu_read_unlock(); } -static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo) -{ - 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); - ret = dma_resv_trylock(bo->base.resv) ? 0 : -EBUSY; - if (!ret) { - if (dma_resv_test_signaled_rcu(&bo->base._resv, true)) { - ttm_bo_del_from_lru(bo); - spin_unlock(&ttm_bo_glob.lru_lock); - if (bo->base.resv != &bo->base._resv) - dma_resv_unlock(&bo->base._resv); - - ttm_bo_cleanup_memtype_use(bo); - dma_resv_unlock(bo->base.resv); - return; - } - - ttm_bo_flush_all_fences(bo); - - /* - * Make NO_EVICT bos immediately available to - * shrinkers, now that they are queued for - * destruction. - */ - if (bo->mem.placement & TTM_PL_FLAG_NO_EVICT) { - bo->mem.placement &= ~TTM_PL_FLAG_NO_EVICT; - ttm_bo_move_to_lru_tail(bo, NULL); - } - - dma_resv_unlock(bo->base.resv); - } - if (bo->base.resv != &bo->base._resv) { - ttm_bo_flush_all_fences(bo); - dma_resv_unlock(&bo->base._resv); - } - -error: - kref_get(&bo->list_kref); - list_add_tail(&bo->ddestroy, &bdev->ddestroy); - spin_unlock(&ttm_bo_glob.lru_lock); - - schedule_delayed_work(&bdev->wq, - ((HZ / 100) < 1) ? 1 : HZ / 100); -} - /** * function ttm_bo_cleanup_refs - * If bo idle, remove from delayed- and lru lists, and unref. - * If not idle, do nothing. + * If bo idle, remove from lru lists, and unref. + * If not idle, block if possible. * * Must be called with lru_lock and reservation held, this function * will drop the lru lock and optionally the reservation lock before returning. @@ -572,14 +484,14 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, ttm_bo_del_from_lru(bo); list_del_init(&bo->ddestroy); - kref_put(&bo->list_kref, ttm_bo_ref_bug); - spin_unlock(&ttm_bo_glob.lru_lock); ttm_bo_cleanup_memtype_use(bo); if (unlock_resv) dma_resv_unlock(bo->base.resv); + ttm_bo_put(bo); + return 0; } @@ -601,8 +513,9 @@ static bool ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all) bo = list_first_entry(&bdev->ddestroy, struct ttm_buffer_object, ddestroy); - kref_get(&bo->list_kref); list_move_tail(&bo->ddestroy, &removed); + if (!ttm_bo_get_unless_zero(bo)) + continue; if (remove_all || bo->base.resv != &bo->base._resv) { spin_unlock(&glob->lru_lock); @@ -617,7 +530,7 @@ static bool ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all) spin_unlock(&glob->lru_lock); } - kref_put(&bo->list_kref, ttm_bo_release_list); + ttm_bo_put(bo); spin_lock(&glob->lru_lock); } list_splice_tail(&removed, &bdev->ddestroy); @@ -643,16 +556,68 @@ 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]; + size_t acc_size = bo->acc_size; + int ret; - if (bo->bdev->driver->release_notify) - bo->bdev->driver->release_notify(bo); + if (!bo->deleted) { + if (bo->bdev->driver->release_notify) + bo->bdev->driver->release_notify(bo); - drm_vma_offset_remove(bdev->vma_manager, &bo->base.vma_node); - ttm_mem_io_lock(man, false); - ttm_mem_io_free_vm(bo); - ttm_mem_io_unlock(man); - ttm_bo_cleanup_refs_or_queue(bo); - kref_put(&bo->list_kref, ttm_bo_release_list); + drm_vma_offset_remove(bdev->vma_manager, &bo->base.vma_node); + ttm_mem_io_lock(man, false); + ttm_mem_io_free_vm(bo); + ttm_mem_io_unlock(man); + + 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 (!dma_resv_test_signaled_rcu(bo->base.resv, true)) { + /* The BO is not idle, resurrect it for delayed destroy */ + ttm_bo_flush_all_fences(bo); + bo->deleted = true; + + spin_lock(&ttm_bo_glob.lru_lock); + + /* + * Make NO_EVICT bos immediately available to + * shrinkers, now that they are queued for + * destruction. + */ + if (bo->mem.placement & TTM_PL_FLAG_NO_EVICT) { + bo->mem.placement &= ~TTM_PL_FLAG_NO_EVICT; + ttm_bo_move_to_lru_tail(bo, NULL); + } + + kref_init(&bo->kref); + list_add_tail(&bo->ddestroy, &bdev->ddestroy); + spin_unlock(&ttm_bo_glob.lru_lock); + + schedule_delayed_work(&bdev->wq, + ((HZ / 100) < 1) ? 1 : HZ / 100); + return; + } + + spin_lock(&ttm_bo_glob.lru_lock); + ttm_bo_del_from_lru(bo); + list_del(&bo->ddestroy); + spin_unlock(&ttm_bo_glob.lru_lock); + + ttm_bo_cleanup_memtype_use(bo); + + BUG_ON(bo->mem.mm_node != NULL); + atomic_dec(&ttm_bo_glob.bo_count); + dma_fence_put(bo->moving); + if (!ttm_bo_uses_embedded_gem_object(bo)) + dma_resv_fini(&bo->base._resv); + bo->destroy(bo); + ttm_mem_global_free(&ttm_mem_glob, acc_size); } void ttm_bo_put(struct ttm_buffer_object *bo) @@ -755,8 +720,7 @@ static bool ttm_bo_evict_swapout_allowable(struct ttm_buffer_object *bo, if (bo->base.resv == ctx->resv) { dma_resv_assert_held(bo->base.resv); - if (ctx->flags & TTM_OPT_FLAG_ALLOW_RES_EVICT - || !list_empty(&bo->ddestroy)) + if (ctx->flags & TTM_OPT_FLAG_ALLOW_RES_EVICT || bo->deleted) ret = true; *locked = false; if (busy) @@ -837,6 +801,11 @@ static int ttm_mem_evict_first(struct ttm_bo_device *bdev, dma_resv_unlock(bo->base.resv); continue; } + if (!ttm_bo_get_unless_zero(bo)) { + if (locked) + dma_resv_unlock(bo->base.resv); + continue; + } break; } @@ -848,21 +817,19 @@ static int ttm_mem_evict_first(struct ttm_bo_device *bdev, } if (!bo) { - if (busy_bo) - kref_get(&busy_bo->list_kref); + if (busy_bo && !ttm_bo_get_unless_zero(busy_bo)) + busy_bo = NULL; spin_unlock(&ttm_bo_glob.lru_lock); ret = ttm_mem_evict_wait_busy(busy_bo, ctx, ticket); if (busy_bo) - kref_put(&busy_bo->list_kref, ttm_bo_release_list); + ttm_bo_put(busy_bo); return ret; } - kref_get(&bo->list_kref); - - if (!list_empty(&bo->ddestroy)) { + if (bo->deleted) { ret = ttm_bo_cleanup_refs(bo, ctx->interruptible, ctx->no_wait_gpu, locked); - kref_put(&bo->list_kref, ttm_bo_release_list); + ttm_bo_put(bo); return ret; } @@ -872,7 +839,7 @@ static int ttm_mem_evict_first(struct ttm_bo_device *bdev, if (locked) ttm_bo_unreserve(bo); - kref_put(&bo->list_kref, ttm_bo_release_list); + ttm_bo_put(bo); return ret; } @@ -1284,7 +1251,6 @@ int ttm_bo_init_reserved(struct ttm_bo_device *bdev, bo->destroy = destroy ? destroy : ttm_bo_default_destroy; kref_init(&bo->kref); - kref_init(&bo->list_kref); INIT_LIST_HEAD(&bo->lru); INIT_LIST_HEAD(&bo->ddestroy); INIT_LIST_HEAD(&bo->swap); @@ -1804,11 +1770,18 @@ int ttm_bo_swapout(struct ttm_bo_global *glob, struct ttm_operation_ctx *ctx) spin_lock(&glob->lru_lock); for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) { list_for_each_entry(bo, &glob->swap_lru[i], swap) { - if (ttm_bo_evict_swapout_allowable(bo, ctx, &locked, - NULL)) { - ret = 0; - break; + if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked, + NULL)) + continue; + + if (!ttm_bo_get_unless_zero(bo)) { + if (locked) + dma_resv_unlock(bo->base.resv); + continue; } + + ret = 0; + break; } if (!ret) break; @@ -1819,11 +1792,9 @@ int ttm_bo_swapout(struct ttm_bo_global *glob, struct ttm_operation_ctx *ctx) return ret; } - kref_get(&bo->list_kref); - - if (!list_empty(&bo->ddestroy)) { + if (bo->deleted) { ret = ttm_bo_cleanup_refs(bo, false, false, locked); - kref_put(&bo->list_kref, ttm_bo_release_list); + ttm_bo_put(bo); return ret; } @@ -1877,7 +1848,7 @@ out: */ if (locked) dma_resv_unlock(bo->base.resv); - kref_put(&bo->list_kref, ttm_bo_release_list); + ttm_bo_put(bo); return ret; } EXPORT_SYMBOL(ttm_bo_swapout); diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index 86d1524..c8e359d 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -507,7 +507,6 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo, fbo->base.moving = NULL; drm_vma_node_reset(&fbo->base.base.vma_node); - kref_init(&fbo->base.list_kref); kref_init(&fbo->base.kref); fbo->base.destroy = &ttm_transfered_destroy; fbo->base.acc_size = 0; diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h index 66ca49d..b9bc1b0 100644 --- a/include/drm/ttm/ttm_bo_api.h +++ b/include/drm/ttm/ttm_bo_api.h @@ -135,18 +135,14 @@ struct ttm_tt; * @num_pages: Actual number of pages. * @acc_size: Accounted size for this object. * @kref: Reference count of this buffer object. When this refcount reaches - * zero, the object is put on the delayed delete list. - * @list_kref: List reference count of this buffer object. This member is - * used to avoid destruction while the buffer object is still on a list. - * Lru lists may keep one refcount, the delayed delete list, and kref != 0 - * keeps one refcount. When this refcount reaches zero, - * the object is destroyed. + * zero, the object is destroyed or put on the delayed delete list. * @mem: structure describing current placement. * @persistent_swap_storage: Usually the swap storage is deleted for buffers * pinned in physical memory. If this behaviour is not desired, this member * holds a pointer to a persistent shmem object. * @ttm: TTM structure holding system pages. * @evicted: Whether the object was evicted without user-space knowing. + * @deleted: True if the object is only a zombie and already deleted. * @lru: List head for the lru list. * @ddestroy: List head for the delayed destroy list. * @swap: List head for swap LRU list. @@ -183,9 +179,7 @@ struct ttm_buffer_object { /** * Members not needing protection. */ - struct kref kref; - struct kref list_kref; /** * Members protected by the bo::resv::reserved lock. @@ -195,6 +189,7 @@ struct ttm_buffer_object { struct file *persistent_swap_storage; struct ttm_tt *ttm; bool evicted; + bool deleted; /** * Members protected by the bdev::lru_lock. -- 2.7.4