1 /* 2 * Copyright © 2008-2010 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 * Authors: 24 * Eric Anholt <eric@anholt.net> 25 * Chris Wilson <chris@chris-wilson.co.uuk> 26 * 27 */ 28 29 #include <drm/drmP.h> 30 #include <drm/i915_drm.h> 31 32 #include "i915_drv.h" 33 #include "intel_drv.h" 34 #include "i915_trace.h" 35 36 static bool ggtt_is_idle(struct drm_i915_private *i915) 37 { 38 struct intel_engine_cs *engine; 39 enum intel_engine_id id; 40 41 if (i915->gt.active_requests) 42 return false; 43 44 for_each_engine(engine, i915, id) { 45 if (engine->last_retired_context != i915->kernel_context) 46 return false; 47 } 48 49 return true; 50 } 51 52 static int ggtt_flush(struct drm_i915_private *i915) 53 { 54 int err; 55 56 /* Not everything in the GGTT is tracked via vma (otherwise we 57 * could evict as required with minimal stalling) so we are forced 58 * to idle the GPU and explicitly retire outstanding requests in 59 * the hopes that we can then remove contexts and the like only 60 * bound by their active reference. 61 */ 62 err = i915_gem_switch_to_kernel_context(i915); 63 if (err) 64 return err; 65 66 err = i915_gem_wait_for_idle(i915, 67 I915_WAIT_INTERRUPTIBLE | 68 I915_WAIT_LOCKED); 69 if (err) 70 return err; 71 72 return 0; 73 } 74 75 static bool 76 mark_free(struct drm_mm_scan *scan, 77 struct i915_vma *vma, 78 unsigned int flags, 79 struct list_head *unwind) 80 { 81 if (i915_vma_is_pinned(vma)) 82 return false; 83 84 if (flags & PIN_NONFAULT && !list_empty(&vma->obj->userfault_link)) 85 return false; 86 87 list_add(&vma->evict_link, unwind); 88 return drm_mm_scan_add_block(scan, &vma->node); 89 } 90 91 /** 92 * i915_gem_evict_something - Evict vmas to make room for binding a new one 93 * @vm: address space to evict from 94 * @min_size: size of the desired free space 95 * @alignment: alignment constraint of the desired free space 96 * @cache_level: cache_level for the desired space 97 * @start: start (inclusive) of the range from which to evict objects 98 * @end: end (exclusive) of the range from which to evict objects 99 * @flags: additional flags to control the eviction algorithm 100 * 101 * This function will try to evict vmas until a free space satisfying the 102 * requirements is found. Callers must check first whether any such hole exists 103 * already before calling this function. 104 * 105 * This function is used by the object/vma binding code. 106 * 107 * Since this function is only used to free up virtual address space it only 108 * ignores pinned vmas, and not object where the backing storage itself is 109 * pinned. Hence obj->pages_pin_count does not protect against eviction. 110 * 111 * To clarify: This is for freeing up virtual address space, not for freeing 112 * memory in e.g. the shrinker. 113 */ 114 int 115 i915_gem_evict_something(struct i915_address_space *vm, 116 u64 min_size, u64 alignment, 117 unsigned cache_level, 118 u64 start, u64 end, 119 unsigned flags) 120 { 121 struct drm_i915_private *dev_priv = vm->i915; 122 struct drm_mm_scan scan; 123 struct list_head eviction_list; 124 struct list_head *phases[] = { 125 &vm->inactive_list, 126 &vm->active_list, 127 NULL, 128 }, **phase; 129 struct i915_vma *vma, *next; 130 struct drm_mm_node *node; 131 enum drm_mm_insert_mode mode; 132 int ret; 133 134 lockdep_assert_held(&vm->i915->drm.struct_mutex); 135 trace_i915_gem_evict(vm, min_size, alignment, flags); 136 137 /* 138 * The goal is to evict objects and amalgamate space in LRU order. 139 * The oldest idle objects reside on the inactive list, which is in 140 * retirement order. The next objects to retire are those in flight, 141 * on the active list, again in retirement order. 142 * 143 * The retirement sequence is thus: 144 * 1. Inactive objects (already retired) 145 * 2. Active objects (will stall on unbinding) 146 * 147 * On each list, the oldest objects lie at the HEAD with the freshest 148 * object on the TAIL. 149 */ 150 mode = DRM_MM_INSERT_BEST; 151 if (flags & PIN_HIGH) 152 mode = DRM_MM_INSERT_HIGH; 153 if (flags & PIN_MAPPABLE) 154 mode = DRM_MM_INSERT_LOW; 155 drm_mm_scan_init_with_range(&scan, &vm->mm, 156 min_size, alignment, cache_level, 157 start, end, mode); 158 159 /* 160 * Retire before we search the active list. Although we have 161 * reasonable accuracy in our retirement lists, we may have 162 * a stray pin (preventing eviction) that can only be resolved by 163 * retiring. 164 */ 165 if (!(flags & PIN_NONBLOCK)) 166 i915_gem_retire_requests(dev_priv); 167 else 168 phases[1] = NULL; 169 170 search_again: 171 INIT_LIST_HEAD(&eviction_list); 172 phase = phases; 173 do { 174 list_for_each_entry(vma, *phase, vm_link) 175 if (mark_free(&scan, vma, flags, &eviction_list)) 176 goto found; 177 } while (*++phase); 178 179 /* Nothing found, clean up and bail out! */ 180 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 181 ret = drm_mm_scan_remove_block(&scan, &vma->node); 182 BUG_ON(ret); 183 } 184 185 /* 186 * Can we unpin some objects such as idle hw contents, 187 * or pending flips? But since only the GGTT has global entries 188 * such as scanouts, rinbuffers and contexts, we can skip the 189 * purge when inspecting per-process local address spaces. 190 */ 191 if (!i915_is_ggtt(vm) || flags & PIN_NONBLOCK) 192 return -ENOSPC; 193 194 /* 195 * Not everything in the GGTT is tracked via VMA using 196 * i915_vma_move_to_active(), otherwise we could evict as required 197 * with minimal stalling. Instead we are forced to idle the GPU and 198 * explicitly retire outstanding requests which will then remove 199 * the pinning for active objects such as contexts and ring, 200 * enabling us to evict them on the next iteration. 201 * 202 * To ensure that all user contexts are evictable, we perform 203 * a switch to the perma-pinned kernel context. This all also gives 204 * us a termination condition, when the last retired context is 205 * the kernel's there is no more we can evict. 206 */ 207 if (!ggtt_is_idle(dev_priv)) { 208 ret = ggtt_flush(dev_priv); 209 if (ret) 210 return ret; 211 212 goto search_again; 213 } 214 215 /* 216 * If we still have pending pageflip completions, drop 217 * back to userspace to give our workqueues time to 218 * acquire our locks and unpin the old scanouts. 219 */ 220 return intel_has_pending_fb_unpin(dev_priv) ? -EAGAIN : -ENOSPC; 221 222 found: 223 /* drm_mm doesn't allow any other other operations while 224 * scanning, therefore store to-be-evicted objects on a 225 * temporary list and take a reference for all before 226 * calling unbind (which may remove the active reference 227 * of any of our objects, thus corrupting the list). 228 */ 229 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 230 if (drm_mm_scan_remove_block(&scan, &vma->node)) 231 __i915_vma_pin(vma); 232 else 233 list_del(&vma->evict_link); 234 } 235 236 /* Unbinding will emit any required flushes */ 237 ret = 0; 238 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 239 __i915_vma_unpin(vma); 240 if (ret == 0) 241 ret = i915_vma_unbind(vma); 242 } 243 244 while (ret == 0 && (node = drm_mm_scan_color_evict(&scan))) { 245 vma = container_of(node, struct i915_vma, node); 246 ret = i915_vma_unbind(vma); 247 } 248 249 return ret; 250 } 251 252 /** 253 * i915_gem_evict_for_vma - Evict vmas to make room for binding a new one 254 * @vm: address space to evict from 255 * @target: range (and color) to evict for 256 * @flags: additional flags to control the eviction algorithm 257 * 258 * This function will try to evict vmas that overlap the target node. 259 * 260 * To clarify: This is for freeing up virtual address space, not for freeing 261 * memory in e.g. the shrinker. 262 */ 263 int i915_gem_evict_for_node(struct i915_address_space *vm, 264 struct drm_mm_node *target, 265 unsigned int flags) 266 { 267 LIST_HEAD(eviction_list); 268 struct drm_mm_node *node; 269 u64 start = target->start; 270 u64 end = start + target->size; 271 struct i915_vma *vma, *next; 272 bool check_color; 273 int ret = 0; 274 275 lockdep_assert_held(&vm->i915->drm.struct_mutex); 276 GEM_BUG_ON(!IS_ALIGNED(start, I915_GTT_PAGE_SIZE)); 277 GEM_BUG_ON(!IS_ALIGNED(end, I915_GTT_PAGE_SIZE)); 278 279 trace_i915_gem_evict_node(vm, target, flags); 280 281 /* Retire before we search the active list. Although we have 282 * reasonable accuracy in our retirement lists, we may have 283 * a stray pin (preventing eviction) that can only be resolved by 284 * retiring. 285 */ 286 if (!(flags & PIN_NONBLOCK)) 287 i915_gem_retire_requests(vm->i915); 288 289 check_color = vm->mm.color_adjust; 290 if (check_color) { 291 /* Expand search to cover neighbouring guard pages (or lack!) */ 292 if (start) 293 start -= I915_GTT_PAGE_SIZE; 294 295 /* Always look at the page afterwards to avoid the end-of-GTT */ 296 end += I915_GTT_PAGE_SIZE; 297 } 298 GEM_BUG_ON(start >= end); 299 300 drm_mm_for_each_node_in_range(node, &vm->mm, start, end) { 301 /* If we find any non-objects (!vma), we cannot evict them */ 302 if (node->color == I915_COLOR_UNEVICTABLE) { 303 ret = -ENOSPC; 304 break; 305 } 306 307 GEM_BUG_ON(!node->allocated); 308 vma = container_of(node, typeof(*vma), node); 309 310 /* If we are using coloring to insert guard pages between 311 * different cache domains within the address space, we have 312 * to check whether the objects on either side of our range 313 * abutt and conflict. If they are in conflict, then we evict 314 * those as well to make room for our guard pages. 315 */ 316 if (check_color) { 317 if (node->start + node->size == target->start) { 318 if (node->color == target->color) 319 continue; 320 } 321 if (node->start == target->start + target->size) { 322 if (node->color == target->color) 323 continue; 324 } 325 } 326 327 if (flags & PIN_NONBLOCK && 328 (i915_vma_is_pinned(vma) || i915_vma_is_active(vma))) { 329 ret = -ENOSPC; 330 break; 331 } 332 333 /* Overlap of objects in the same batch? */ 334 if (i915_vma_is_pinned(vma)) { 335 ret = -ENOSPC; 336 if (vma->exec_flags && 337 *vma->exec_flags & EXEC_OBJECT_PINNED) 338 ret = -EINVAL; 339 break; 340 } 341 342 /* Never show fear in the face of dragons! 343 * 344 * We cannot directly remove this node from within this 345 * iterator and as with i915_gem_evict_something() we employ 346 * the vma pin_count in order to prevent the action of 347 * unbinding one vma from freeing (by dropping its active 348 * reference) another in our eviction list. 349 */ 350 __i915_vma_pin(vma); 351 list_add(&vma->evict_link, &eviction_list); 352 } 353 354 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 355 __i915_vma_unpin(vma); 356 if (ret == 0) 357 ret = i915_vma_unbind(vma); 358 } 359 360 return ret; 361 } 362 363 /** 364 * i915_gem_evict_vm - Evict all idle vmas from a vm 365 * @vm: Address space to cleanse 366 * 367 * This function evicts all vmas from a vm. 368 * 369 * This is used by the execbuf code as a last-ditch effort to defragment the 370 * address space. 371 * 372 * To clarify: This is for freeing up virtual address space, not for freeing 373 * memory in e.g. the shrinker. 374 */ 375 int i915_gem_evict_vm(struct i915_address_space *vm) 376 { 377 struct list_head *phases[] = { 378 &vm->inactive_list, 379 &vm->active_list, 380 NULL 381 }, **phase; 382 struct list_head eviction_list; 383 struct i915_vma *vma, *next; 384 int ret; 385 386 lockdep_assert_held(&vm->i915->drm.struct_mutex); 387 trace_i915_gem_evict_vm(vm); 388 389 /* Switch back to the default context in order to unpin 390 * the existing context objects. However, such objects only 391 * pin themselves inside the global GTT and performing the 392 * switch otherwise is ineffective. 393 */ 394 if (i915_is_ggtt(vm)) { 395 ret = ggtt_flush(vm->i915); 396 if (ret) 397 return ret; 398 } 399 400 INIT_LIST_HEAD(&eviction_list); 401 phase = phases; 402 do { 403 list_for_each_entry(vma, *phase, vm_link) { 404 if (i915_vma_is_pinned(vma)) 405 continue; 406 407 __i915_vma_pin(vma); 408 list_add(&vma->evict_link, &eviction_list); 409 } 410 } while (*++phase); 411 412 ret = 0; 413 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 414 __i915_vma_unpin(vma); 415 if (ret == 0) 416 ret = i915_vma_unbind(vma); 417 } 418 return ret; 419 } 420 421 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) 422 #include "selftests/i915_gem_evict.c" 423 #endif 424