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 * @engine: the associated request submission engine 45 * @pool: the batch buffer pool 46 */ 47 void i915_gem_batch_pool_init(struct intel_engine_cs *engine, 48 struct i915_gem_batch_pool *pool) 49 { 50 int n; 51 52 pool->engine = engine; 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 lockdep_assert_held(&pool->engine->i915->drm.struct_mutex); 69 70 for (n = 0; n < ARRAY_SIZE(pool->cache_list); n++) { 71 struct drm_i915_gem_object *obj, *next; 72 73 list_for_each_entry_safe(obj, next, 74 &pool->cache_list[n], 75 batch_pool_link) 76 __i915_gem_object_release_unless_active(obj); 77 78 INIT_LIST_HEAD(&pool->cache_list[n]); 79 } 80 } 81 82 /** 83 * i915_gem_batch_pool_get() - allocate a buffer from the pool 84 * @pool: the batch buffer pool 85 * @size: the minimum desired size of the returned buffer 86 * 87 * Returns an inactive buffer from @pool with at least @size bytes, 88 * with the pages pinned. The caller must i915_gem_object_unpin_pages() 89 * on the returned object. 90 * 91 * Note: Callers must hold the struct_mutex 92 * 93 * Return: the buffer object or an error pointer 94 */ 95 struct drm_i915_gem_object * 96 i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool, 97 size_t size) 98 { 99 struct drm_i915_gem_object *obj; 100 struct list_head *list; 101 int n, ret; 102 103 lockdep_assert_held(&pool->engine->i915->drm.struct_mutex); 104 105 /* Compute a power-of-two bucket, but throw everything greater than 106 * 16KiB into the same bucket: i.e. the the buckets hold objects of 107 * (1 page, 2 pages, 4 pages, 8+ pages). 108 */ 109 n = fls(size >> PAGE_SHIFT) - 1; 110 if (n >= ARRAY_SIZE(pool->cache_list)) 111 n = ARRAY_SIZE(pool->cache_list) - 1; 112 list = &pool->cache_list[n]; 113 114 list_for_each_entry(obj, list, batch_pool_link) { 115 /* The batches are strictly LRU ordered */ 116 if (i915_gem_object_is_active(obj)) { 117 struct reservation_object *resv = obj->resv; 118 119 if (!reservation_object_test_signaled_rcu(resv, true)) 120 break; 121 122 i915_gem_retire_requests(pool->engine->i915); 123 GEM_BUG_ON(i915_gem_object_is_active(obj)); 124 125 /* 126 * The object is now idle, clear the array of shared 127 * fences before we add a new request. Although, we 128 * remain on the same engine, we may be on a different 129 * timeline and so may continually grow the array, 130 * trapping a reference to all the old fences, rather 131 * than replace the existing fence. 132 */ 133 if (rcu_access_pointer(resv->fence)) { 134 reservation_object_lock(resv, NULL); 135 reservation_object_add_excl_fence(resv, NULL); 136 reservation_object_unlock(resv); 137 } 138 } 139 140 GEM_BUG_ON(!reservation_object_test_signaled_rcu(obj->resv, 141 true)); 142 143 if (obj->base.size >= size) 144 goto found; 145 } 146 147 obj = i915_gem_object_create_internal(pool->engine->i915, size); 148 if (IS_ERR(obj)) 149 return obj; 150 151 found: 152 ret = i915_gem_object_pin_pages(obj); 153 if (ret) 154 return ERR_PTR(ret); 155 156 list_move_tail(&obj->batch_pool_link, list); 157 return obj; 158 } 159