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([10.245.244.226]) by fmviesa010-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jul 2024 08:38:35 -0700 From: =?utf-8?q?Thomas_Hellstr=C3=B6m?= To: intel-xe@lists.freedesktop.org Cc: =?utf-8?q?Thomas_Hellstr=C3=B6m?= , =?utf-8?q?Christian_K=C3=B6nig?= , Somalapuram Amaranath , Matthew Brost , dri-devel@lists.freedesktop.org Subject: [PATCH v6 07/12] drm/ttm: Use the LRU walker for eviction Date: Wed, 3 Jul 2024 17:38:08 +0200 Message-ID: <20240703153813.182001-8-thomas.hellstrom@linux.intel.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240703153813.182001-1-thomas.hellstrom@linux.intel.com> References: <20240703153813.182001-1-thomas.hellstrom@linux.intel.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Use the LRU walker for eviction. This helps removing a lot of code with weird locking semantics. The functionality is slightly changed so that when trylocked buffer objects are exhausted, we continue to interleave walks with ticket-locks while there is still progress made. The list walks are not restarted in-between evictions. Also provide a separate ttm_bo_evict_first() function for its single user. The context of that user allows sleeping dma_resv locks. v6: - Various cleanups suggested by Matthew Brost. - Fix error return code of ttm_bo_evict_first(). (Matthew Brost) - Fix an error check that was inverted. (Matthew Brost) Cc: Christian König Cc: Somalapuram Amaranath Cc: Matthew Brost Cc: Signed-off-by: Thomas Hellström Reviewed-by: Matthew Brost --- drivers/gpu/drm/ttm/ttm_bo.c | 346 ++++++++++++----------------- drivers/gpu/drm/ttm/ttm_resource.c | 21 +- include/drm/ttm/ttm_bo.h | 8 +- 3 files changed, 144 insertions(+), 231 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 1053cdca131e..603b9353f436 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -224,80 +224,6 @@ static void ttm_bo_flush_all_fences(struct ttm_buffer_object *bo) dma_resv_iter_end(&cursor); } -/** - * ttm_bo_cleanup_refs - * 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. - * - * @bo: The buffer object to clean-up - * @interruptible: Any sleeps should occur interruptibly. - * @no_wait_gpu: Never wait for gpu. Return -EBUSY instead. - * @unlock_resv: Unlock the reservation lock as well. - */ - -static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, - bool interruptible, bool no_wait_gpu, - bool unlock_resv) -{ - struct dma_resv *resv = &bo->base._resv; - int ret; - - if (dma_resv_test_signaled(resv, DMA_RESV_USAGE_BOOKKEEP)) - ret = 0; - else - ret = -EBUSY; - - if (ret && !no_wait_gpu) { - long lret; - - if (unlock_resv) - dma_resv_unlock(bo->base.resv); - spin_unlock(&bo->bdev->lru_lock); - - lret = dma_resv_wait_timeout(resv, DMA_RESV_USAGE_BOOKKEEP, - interruptible, - 30 * HZ); - - if (lret < 0) - return lret; - else if (lret == 0) - return -EBUSY; - - spin_lock(&bo->bdev->lru_lock); - if (unlock_resv && !dma_resv_trylock(bo->base.resv)) { - /* - * We raced, and lost, someone else holds the reservation now, - * and is probably busy in ttm_bo_cleanup_memtype_use. - * - * Even if it's not the case, because we finished waiting any - * delayed destruction would succeed, so just return success - * here. - */ - spin_unlock(&bo->bdev->lru_lock); - return 0; - } - ret = 0; - } - - if (ret) { - if (unlock_resv) - dma_resv_unlock(bo->base.resv); - spin_unlock(&bo->bdev->lru_lock); - return ret; - } - - spin_unlock(&bo->bdev->lru_lock); - ttm_bo_cleanup_memtype_use(bo); - - if (unlock_resv) - dma_resv_unlock(bo->base.resv); - - return 0; -} - /* * Block for the dma_resv object to become idle, lock the buffer and clean up * the resource and tt object. @@ -505,151 +431,153 @@ bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo, } EXPORT_SYMBOL(ttm_bo_eviction_valuable); -/* - * Check the target bo is allowable to be evicted or swapout, including cases: - * - * a. if share same reservation object with ctx->resv, have assumption - * reservation objects should already be locked, so not lock again and - * return true directly when either the opreation allow_reserved_eviction - * or the target bo already is in delayed free list; +/** + * ttm_bo_evict_first() - Evict the first bo on the manager's LRU list. + * @bdev: The ttm device. + * @man: The manager whose bo to evict. + * @ctx: The TTM operation ctx governing the eviction. * - * b. Otherwise, trylock it. + * Return: 0 if successful or the resource disappeared. Negative error code on error. */ -static bool ttm_bo_evict_swapout_allowable(struct ttm_buffer_object *bo, - struct ttm_operation_ctx *ctx, - const struct ttm_place *place, - bool *locked, bool *busy) +int ttm_bo_evict_first(struct ttm_device *bdev, struct ttm_resource_manager *man, + struct ttm_operation_ctx *ctx) { - bool ret = false; + struct ttm_resource_cursor cursor; + struct ttm_buffer_object *bo; + struct ttm_resource *res; + unsigned int mem_type; + int ret = 0; - if (bo->pin_count) { - *locked = false; - if (busy) - *busy = false; - return false; + spin_lock(&bdev->lru_lock); + res = ttm_resource_manager_first(man, &cursor); + if (!res) { + ret = -ENOENT; + goto out_no_ref; } + bo = res->bo; + if (!ttm_bo_get_unless_zero(bo)) + goto out_no_ref; + mem_type = res->mem_type; + spin_unlock(&bdev->lru_lock); + ret = ttm_bo_reserve(bo, ctx->interruptible, ctx->no_wait_gpu, NULL); + if (ret) + goto out_no_lock; + if (bo->resource != res || res->mem_type != mem_type) + goto out_bo_moved; - if (bo->base.resv == ctx->resv) { - dma_resv_assert_held(bo->base.resv); - if (ctx->allow_res_evict) - ret = true; - *locked = false; - if (busy) - *busy = false; + if (bo->deleted) { + ret = ttm_bo_wait_ctx(bo, ctx); + if (!ret) + ttm_bo_cleanup_memtype_use(bo); } else { - ret = dma_resv_trylock(bo->base.resv); - *locked = ret; - if (busy) - *busy = !ret; - } - - if (ret && place && (bo->resource->mem_type != place->mem_type || - !bo->bdev->funcs->eviction_valuable(bo, place))) { - ret = false; - if (*locked) { - dma_resv_unlock(bo->base.resv); - *locked = false; - } + ret = ttm_bo_evict(bo, ctx); } +out_bo_moved: + dma_resv_unlock(bo->base.resv); +out_no_lock: + ttm_bo_put(bo); + ttm_resource_cursor_fini(&cursor); + return ret; +out_no_ref: + ttm_resource_cursor_fini_locked(&cursor); + spin_unlock(&bdev->lru_lock); return ret; } /** - * ttm_mem_evict_wait_busy - wait for a busy BO to become available - * - * @busy_bo: BO which couldn't be locked with trylock - * @ctx: operation context - * @ticket: acquire ticket - * - * Try to lock a busy buffer object to avoid failing eviction. + * struct ttm_bo_evict_walk - Parameters for the evict walk. */ -static int ttm_mem_evict_wait_busy(struct ttm_buffer_object *busy_bo, - struct ttm_operation_ctx *ctx, - struct ww_acquire_ctx *ticket) -{ - int r; - - if (!busy_bo || !ticket) - return -EBUSY; - - if (ctx->interruptible) - r = dma_resv_lock_interruptible(busy_bo->base.resv, - ticket); - else - r = dma_resv_lock(busy_bo->base.resv, ticket); - - /* - * TODO: It would be better to keep the BO locked until allocation is at - * least tried one more time, but that would mean a much larger rework - * of TTM. - */ - if (!r) - dma_resv_unlock(busy_bo->base.resv); - - return r == -EDEADLK ? -EBUSY : r; -} +struct ttm_bo_evict_walk { + /** @walk: The walk base parameters. */ + struct ttm_lru_walk walk; + /** @place: The place passed to the resource allocation. */ + const struct ttm_place *place; + /** @evictor: The buffer object we're trying to make room for. */ + struct ttm_buffer_object *evictor; + /** @res: The allocated resource if any. */ + struct ttm_resource **res; + /** @evicted: Number of successful evictions. */ + unsigned long evicted; +}; -int ttm_mem_evict_first(struct ttm_device *bdev, - struct ttm_resource_manager *man, - const struct ttm_place *place, - struct ttm_operation_ctx *ctx, - struct ww_acquire_ctx *ticket) +static long ttm_bo_evict_cb(struct ttm_lru_walk *walk, struct ttm_buffer_object *bo) { - struct ttm_buffer_object *bo = NULL, *busy_bo = NULL; - struct ttm_resource_cursor cursor; - struct ttm_resource *res; - bool locked = false; - int ret; + struct ttm_bo_evict_walk *evict_walk = + container_of(walk, typeof(*evict_walk), walk); + long lret; - spin_lock(&bdev->lru_lock); - ttm_resource_manager_for_each_res(man, &cursor, res) { - bool busy; - - if (!ttm_bo_evict_swapout_allowable(res->bo, ctx, place, - &locked, &busy)) { - if (busy && !busy_bo && ticket != - dma_resv_locking_ctx(res->bo->base.resv)) - busy_bo = res->bo; - continue; - } + if (!bo->bdev->funcs->eviction_valuable(bo, evict_walk->place)) + return 0; - if (ttm_bo_get_unless_zero(res->bo)) { - bo = res->bo; - break; - } - if (locked) - dma_resv_unlock(res->bo->base.resv); + if (bo->deleted) { + lret = ttm_bo_wait_ctx(bo, walk->ctx); + if (!lret) + ttm_bo_cleanup_memtype_use(bo); + } else { + lret = ttm_bo_evict(bo, walk->ctx); } - ttm_resource_cursor_fini_locked(&cursor); - if (!bo) { - if (busy_bo && !ttm_bo_get_unless_zero(busy_bo)) - busy_bo = NULL; - spin_unlock(&bdev->lru_lock); - ret = ttm_mem_evict_wait_busy(busy_bo, ctx, ticket); - if (busy_bo) - ttm_bo_put(busy_bo); - return ret; - } + if (lret) + goto out; - if (bo->deleted) { - ret = ttm_bo_cleanup_refs(bo, ctx->interruptible, - ctx->no_wait_gpu, locked); - ttm_bo_put(bo); - return ret; - } + evict_walk->evicted++; + if (evict_walk->res) + lret = ttm_resource_alloc(evict_walk->evictor, evict_walk->place, + evict_walk->res); + if (lret == 0) + return 1; +out: + /* Errors that should terminate the walk. */ + if (lret == -ENOSPC) + return -EBUSY; - spin_unlock(&bdev->lru_lock); + return lret; +} - ret = ttm_bo_evict(bo, ctx); - if (locked) - ttm_bo_unreserve(bo); - else - ttm_bo_move_to_lru_tail_unlocked(bo); +static const struct ttm_lru_walk_ops ttm_evict_walk_ops = { + .process_bo = ttm_bo_evict_cb, +}; - ttm_bo_put(bo); - return ret; +static int ttm_bo_evict_alloc(struct ttm_device *bdev, + struct ttm_resource_manager *man, + const struct ttm_place *place, + struct ttm_buffer_object *evictor, + struct ttm_operation_ctx *ctx, + struct ww_acquire_ctx *ticket, + struct ttm_resource **res) +{ + struct ttm_bo_evict_walk evict_walk = { + .walk = { + .ops = &ttm_evict_walk_ops, + .ctx = ctx, + .ticket = ticket, + }, + .place = place, + .evictor = evictor, + .res = res, + }; + long lret; + + evict_walk.walk.trylock_only = true; + lret = ttm_lru_walk_for_evict(&evict_walk.walk, bdev, man, 1); + if (lret || !ticket) + goto out; + + /* If ticket-locking, repeat while making progress. */ + evict_walk.walk.trylock_only = false; + do { + /* The walk may clear the evict_walk.walk.ticket field */ + evict_walk.walk.ticket = ticket; + evict_walk.evicted = 0; + lret = ttm_lru_walk_for_evict(&evict_walk.walk, bdev, man, 1); + } while (!lret && evict_walk.evicted); +out: + if (lret < 0) + return lret; + if (lret == 0) + return -EBUSY; + return 0; } /** @@ -760,6 +688,7 @@ static int ttm_bo_alloc_resource(struct ttm_buffer_object *bo, for (i = 0; i < placement->num_placement; ++i) { const struct ttm_place *place = &placement->placement[i]; struct ttm_resource_manager *man; + bool may_evict; man = ttm_manager_type(bdev, place->mem_type); if (!man || !ttm_resource_manager_used(man)) @@ -769,22 +698,21 @@ static int ttm_bo_alloc_resource(struct ttm_buffer_object *bo, TTM_PL_FLAG_FALLBACK)) continue; - do { - ret = ttm_resource_alloc(bo, place, res); - if (unlikely(ret && ret != -ENOSPC)) + may_evict = (force_space && place->mem_type != TTM_PL_SYSTEM); + ret = ttm_resource_alloc(bo, place, res); + if (ret) { + if (ret != -ENOSPC) return ret; - if (likely(!ret) || !force_space) - break; - - ret = ttm_mem_evict_first(bdev, man, place, ctx, - ticket); - if (unlikely(ret == -EBUSY)) - break; - if (unlikely(ret)) + if (!may_evict) + continue; + + ret = ttm_bo_evict_alloc(bdev, man, place, bo, ctx, + ticket, res); + if (ret == -EBUSY) + continue; + if (ret) return ret; - } while (1); - if (ret) - continue; + } ret = ttm_bo_add_move_fence(bo, man, ctx->no_wait_gpu); if (unlikely(ret)) { diff --git a/drivers/gpu/drm/ttm/ttm_resource.c b/drivers/gpu/drm/ttm/ttm_resource.c index b6a2daac5518..9dc727d416cc 100644 --- a/drivers/gpu/drm/ttm/ttm_resource.c +++ b/drivers/gpu/drm/ttm/ttm_resource.c @@ -512,24 +512,11 @@ int ttm_resource_manager_evict_all(struct ttm_device *bdev, }; struct dma_fence *fence; int ret; - unsigned i; - - /* - * Can't use standard list traversal since we're unlocking. - */ - spin_lock(&bdev->lru_lock); - for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) { - while (!list_empty(&man->lru[i])) { - spin_unlock(&bdev->lru_lock); - ret = ttm_mem_evict_first(bdev, man, NULL, &ctx, - NULL); - if (ret) - return ret; - spin_lock(&bdev->lru_lock); - } - } - spin_unlock(&bdev->lru_lock); + do { + ret = ttm_bo_evict_first(bdev, man, &ctx); + cond_resched(); + } while (!ret); spin_lock(&man->move_lock); fence = dma_fence_get(man->move); diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h index de97ea9fa75f..e577528f5dfc 100644 --- a/include/drm/ttm/ttm_bo.h +++ b/include/drm/ttm/ttm_bo.h @@ -422,11 +422,9 @@ long ttm_bo_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx, pgoff_t target); void ttm_bo_pin(struct ttm_buffer_object *bo); void ttm_bo_unpin(struct ttm_buffer_object *bo); -int ttm_mem_evict_first(struct ttm_device *bdev, - struct ttm_resource_manager *man, - const struct ttm_place *place, - struct ttm_operation_ctx *ctx, - struct ww_acquire_ctx *ticket); +int ttm_bo_evict_first(struct ttm_device *bdev, + struct ttm_resource_manager *man, + struct ttm_operation_ctx *ctx); vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo, struct vm_fault *vmf); vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,