1 /* 2 * Copyright © 2014 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 */ 24 25 #include "i915_drv.h" 26 #include "i915_gem_batch_pool.h" 27 28 /** 29 * DOC: batch pool 30 * 31 * In order to submit batch buffers as 'secure', the software command parser 32 * must ensure that a batch buffer cannot be modified after parsing. It does 33 * this by copying the user provided batch buffer contents to a kernel owned 34 * buffer from which the hardware will actually execute, and by carefully 35 * managing the address space bindings for such buffers. 36 * 37 * The batch pool framework provides a mechanism for the driver to manage a 38 * set of scratch buffers to use for this purpose. The framework can be 39 * extended to support other uses cases should they arise. 40 */ 41 42 /** 43 * i915_gem_batch_pool_init() - initialize a batch buffer pool 44 * @dev: the drm device 45 * @pool: the batch buffer pool 46 */ 47 void i915_gem_batch_pool_init(struct drm_device *dev, 48 struct i915_gem_batch_pool *pool) 49 { 50 int n; 51 52 pool->dev = dev; 53 54 for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) 55 INIT_LIST_HEAD(&pool->cache_list[n]); 56 } 57 58 /** 59 * i915_gem_batch_pool_fini() - clean up a batch buffer pool 60 * @pool: the pool to clean up 61 * 62 * Note: Callers must hold the struct_mutex. 63 */ 64 void i915_gem_batch_pool_fini(struct i915_gem_batch_pool *pool) 65 { 66 int n; 67 68 WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex)); 69 70 for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) { 71 while (!list_empty(&pool->cache_list[n])) { 72 struct drm_i915_gem_object *obj = 73 list_first_entry(&pool->cache_list[n], 74 struct drm_i915_gem_object, 75 batch_pool_link); 76 77 list_del(&obj->batch_pool_link); 78 drm_gem_object_unreference(&obj->base); 79 } 80 } 81 } 82 83 /** 84 * i915_gem_batch_pool_get() - allocate a buffer from the pool 85 * @pool: the batch buffer pool 86 * @size: the minimum desired size of the returned buffer 87 * 88 * Returns an inactive buffer from @pool with at least @size bytes, 89 * with the pages pinned. The caller must i915_gem_object_unpin_pages() 90 * on the returned object. 91 * 92 * Note: Callers must hold the struct_mutex 93 * 94 * Return: the buffer object or an error pointer 95 */ 96 struct drm_i915_gem_object * 97 i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool, 98 size_t size) 99 { 100 struct drm_i915_gem_object *obj = NULL; 101 struct drm_i915_gem_object *tmp, *next; 102 struct list_head *list; 103 int n; 104 105 WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex)); 106 107 /* Compute a power-of-two bucket, but throw everything greater than 108 * 16KiB into the same bucket: i.e. the the buckets hold objects of 109 * (1 page, 2 pages, 4 pages, 8+ pages). 110 */ 111 n = fls(size >> PAGE_SHIFT) - 1; 112 if (n >= ARRAY_SIZE(pool->cache_list)) 113 n = ARRAY_SIZE(pool->cache_list) - 1; 114 list = &pool->cache_list[n]; 115 116 list_for_each_entry_safe(tmp, next, list, batch_pool_link) { 117 /* The batches are strictly LRU ordered */ 118 if (tmp->active) 119 break; 120 121 /* While we're looping, do some clean up */ 122 if (tmp->madv == __I915_MADV_PURGED) { 123 list_del(&tmp->batch_pool_link); 124 drm_gem_object_unreference(&tmp->base); 125 continue; 126 } 127 128 if (tmp->base.size >= size) { 129 obj = tmp; 130 break; 131 } 132 } 133 134 if (obj == NULL) { 135 int ret; 136 137 obj = i915_gem_alloc_object(pool->dev, size); 138 if (obj == NULL) 139 return ERR_PTR(-ENOMEM); 140 141 ret = i915_gem_object_get_pages(obj); 142 if (ret) 143 return ERR_PTR(ret); 144 145 obj->madv = I915_MADV_DONTNEED; 146 } 147 148 list_move_tail(&obj->batch_pool_link, list); 149 i915_gem_object_pin_pages(obj); 150 return obj; 151 } 152