1 /************************************************************************** 2 * 3 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA 4 * All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the 8 * "Software"), to deal in the Software without restriction, including 9 * without limitation the rights to use, copy, modify, merge, publish, 10 * distribute, sub license, and/or sell copies of the Software, and to 11 * permit persons to whom the Software is furnished to do so, subject to 12 * the following conditions: 13 * 14 * The above copyright notice and this permission notice (including the 15 * next paragraph) shall be included in all copies or substantial portions 16 * of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 24 * USE OR OTHER DEALINGS IN THE SOFTWARE. 25 * 26 **************************************************************************/ 27 28 #include <drm/ttm/ttm_execbuf_util.h> 29 #include <drm/ttm/ttm_bo_driver.h> 30 #include <drm/ttm/ttm_placement.h> 31 #include <linux/export.h> 32 33 static void ttm_eu_backoff_reservation_locked(struct list_head *list) 34 { 35 struct ttm_validate_buffer *entry; 36 37 list_for_each_entry(entry, list, head) { 38 struct ttm_buffer_object *bo = entry->bo; 39 if (!entry->reserved) 40 continue; 41 42 if (entry->removed) { 43 ttm_bo_add_to_lru(bo); 44 entry->removed = false; 45 46 } 47 entry->reserved = false; 48 atomic_set(&bo->reserved, 0); 49 wakeup(bo); 50 } 51 } 52 53 static void ttm_eu_del_from_lru_locked(struct list_head *list) 54 { 55 struct ttm_validate_buffer *entry; 56 57 list_for_each_entry(entry, list, head) { 58 struct ttm_buffer_object *bo = entry->bo; 59 if (!entry->reserved) 60 continue; 61 62 if (!entry->removed) { 63 entry->put_count = ttm_bo_del_from_lru(bo); 64 entry->removed = true; 65 } 66 } 67 } 68 69 static void ttm_eu_list_ref_sub(struct list_head *list) 70 { 71 struct ttm_validate_buffer *entry; 72 73 list_for_each_entry(entry, list, head) { 74 struct ttm_buffer_object *bo = entry->bo; 75 76 if (entry->put_count) { 77 ttm_bo_list_ref_sub(bo, entry->put_count, true); 78 entry->put_count = 0; 79 } 80 } 81 } 82 83 void ttm_eu_backoff_reservation(struct list_head *list) 84 { 85 struct ttm_validate_buffer *entry; 86 struct ttm_bo_global *glob; 87 88 if (list_empty(list)) 89 return; 90 91 entry = list_first_entry(list, struct ttm_validate_buffer, head); 92 glob = entry->bo->glob; 93 lockmgr(&glob->lru_lock, LK_EXCLUSIVE); 94 ttm_eu_backoff_reservation_locked(list); 95 lockmgr(&glob->lru_lock, LK_RELEASE); 96 } 97 EXPORT_SYMBOL(ttm_eu_backoff_reservation); 98 99 /* 100 * Reserve buffers for validation. 101 * 102 * If a buffer in the list is marked for CPU access, we back off and 103 * wait for that buffer to become free for GPU access. 104 * 105 * If a buffer is reserved for another validation, the validator with 106 * the highest validation sequence backs off and waits for that buffer 107 * to become unreserved. This prevents deadlocks when validating multiple 108 * buffers in different orders. 109 */ 110 111 int ttm_eu_reserve_buffers(struct list_head *list) 112 { 113 struct ttm_bo_global *glob; 114 struct ttm_validate_buffer *entry; 115 int ret; 116 uint32_t val_seq; 117 118 if (list_empty(list)) 119 return 0; 120 121 list_for_each_entry(entry, list, head) { 122 entry->reserved = false; 123 entry->put_count = 0; 124 entry->removed = false; 125 } 126 127 entry = list_first_entry(list, struct ttm_validate_buffer, head); 128 glob = entry->bo->glob; 129 130 lockmgr(&glob->lru_lock, LK_EXCLUSIVE); 131 val_seq = entry->bo->bdev->val_seq++; 132 133 retry: 134 list_for_each_entry(entry, list, head) { 135 struct ttm_buffer_object *bo = entry->bo; 136 137 /* already slowpath reserved? */ 138 if (entry->reserved) 139 continue; 140 141 ret = ttm_bo_reserve_nolru(bo, true, true, true, val_seq); 142 switch (ret) { 143 case 0: 144 break; 145 case -EBUSY: 146 ttm_eu_del_from_lru_locked(list); 147 lockmgr(&glob->lru_lock, LK_RELEASE); 148 ret = ttm_bo_reserve_nolru(bo, true, false, 149 true, val_seq); 150 lockmgr(&glob->lru_lock, LK_EXCLUSIVE); 151 if (!ret) 152 break; 153 154 if (unlikely(ret != -EAGAIN)) 155 goto err; 156 157 /* fallthrough */ 158 case -EAGAIN: 159 ttm_eu_backoff_reservation_locked(list); 160 161 /* 162 * temporarily increase sequence number every retry, 163 * to prevent us from seeing our old reservation 164 * sequence when someone else reserved the buffer, 165 * but hasn't updated the seq_valid/seqno members yet. 166 */ 167 val_seq = entry->bo->bdev->val_seq++; 168 169 lockmgr(&glob->lru_lock, LK_RELEASE); 170 ttm_eu_list_ref_sub(list); 171 ret = ttm_bo_reserve_slowpath_nolru(bo, true, val_seq); 172 if (unlikely(ret != 0)) 173 return ret; 174 lockmgr(&glob->lru_lock, LK_EXCLUSIVE); 175 entry->reserved = true; 176 if (unlikely(atomic_read(&bo->cpu_writers) > 0)) { 177 ret = -EBUSY; 178 goto err; 179 } 180 goto retry; 181 default: 182 goto err; 183 } 184 185 entry->reserved = true; 186 if (unlikely(atomic_read(&bo->cpu_writers) > 0)) { 187 ret = -EBUSY; 188 goto err; 189 } 190 } 191 192 ttm_eu_del_from_lru_locked(list); 193 lockmgr(&glob->lru_lock, LK_RELEASE); 194 ttm_eu_list_ref_sub(list); 195 196 return 0; 197 198 err: 199 ttm_eu_backoff_reservation_locked(list); 200 lockmgr(&glob->lru_lock, LK_RELEASE); 201 ttm_eu_list_ref_sub(list); 202 return ret; 203 } 204 EXPORT_SYMBOL(ttm_eu_reserve_buffers); 205 206 void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj) 207 { 208 struct ttm_validate_buffer *entry; 209 struct ttm_buffer_object *bo; 210 struct ttm_bo_global *glob; 211 struct ttm_bo_device *bdev; 212 struct ttm_bo_driver *driver; 213 214 if (list_empty(list)) 215 return; 216 217 bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo; 218 bdev = bo->bdev; 219 driver = bdev->driver; 220 glob = bo->glob; 221 222 lockmgr(&glob->lru_lock, LK_EXCLUSIVE); 223 lockmgr(&bdev->fence_lock, LK_EXCLUSIVE); 224 225 list_for_each_entry(entry, list, head) { 226 bo = entry->bo; 227 entry->old_sync_obj = bo->sync_obj; 228 bo->sync_obj = driver->sync_obj_ref(sync_obj); 229 ttm_bo_unreserve_locked(bo); 230 entry->reserved = false; 231 } 232 lockmgr(&bdev->fence_lock, LK_RELEASE); 233 lockmgr(&glob->lru_lock, LK_RELEASE); 234 235 list_for_each_entry(entry, list, head) { 236 if (entry->old_sync_obj) 237 driver->sync_obj_unref(&entry->old_sync_obj); 238 } 239 } 240 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects); 241