1 /* 2 * Copyright © 2008-2015 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 <linux/oom.h> 26 #include <linux/shmem_fs.h> 27 #include <linux/slab.h> 28 #include <linux/swap.h> 29 #include <linux/pci.h> 30 #include <linux/dma-buf.h> 31 #include <linux/vmalloc.h> 32 #include <drm/drmP.h> 33 #include <drm/i915_drm.h> 34 35 #include "i915_drv.h" 36 #include "i915_trace.h" 37 38 static bool shrinker_lock(struct drm_i915_private *dev_priv, bool *unlock) 39 { 40 switch (mutex_trylock_recursive(&dev_priv->drm.struct_mutex)) { 41 case MUTEX_TRYLOCK_RECURSIVE: 42 *unlock = false; 43 return true; 44 45 case MUTEX_TRYLOCK_FAILED: 46 *unlock = false; 47 preempt_disable(); 48 do { 49 cpu_relax(); 50 if (mutex_trylock(&dev_priv->drm.struct_mutex)) { 51 *unlock = true; 52 break; 53 } 54 } while (!need_resched()); 55 preempt_enable(); 56 return *unlock; 57 58 case MUTEX_TRYLOCK_SUCCESS: 59 *unlock = true; 60 return true; 61 } 62 63 BUG(); 64 } 65 66 static void shrinker_unlock(struct drm_i915_private *dev_priv, bool unlock) 67 { 68 if (!unlock) 69 return; 70 71 mutex_unlock(&dev_priv->drm.struct_mutex); 72 } 73 74 static bool swap_available(void) 75 { 76 return get_nr_swap_pages() > 0; 77 } 78 79 static bool can_release_pages(struct drm_i915_gem_object *obj) 80 { 81 /* Consider only shrinkable ojects. */ 82 if (!i915_gem_object_is_shrinkable(obj)) 83 return false; 84 85 /* Only report true if by unbinding the object and putting its pages 86 * we can actually make forward progress towards freeing physical 87 * pages. 88 * 89 * If the pages are pinned for any other reason than being bound 90 * to the GPU, simply unbinding from the GPU is not going to succeed 91 * in releasing our pin count on the pages themselves. 92 */ 93 if (atomic_read(&obj->mm.pages_pin_count) > obj->bind_count) 94 return false; 95 96 /* If any vma are "permanently" pinned, it will prevent us from 97 * reclaiming the obj->mm.pages. We only allow scanout objects to claim 98 * a permanent pin, along with a few others like the context objects. 99 * To simplify the scan, and to avoid walking the list of vma under the 100 * object, we just check the count of its permanently pinned. 101 */ 102 if (READ_ONCE(obj->pin_global)) 103 return false; 104 105 /* We can only return physical pages to the system if we can either 106 * discard the contents (because the user has marked them as being 107 * purgeable) or if we can move their contents out to swap. 108 */ 109 return swap_available() || obj->mm.madv == I915_MADV_DONTNEED; 110 } 111 112 static bool unsafe_drop_pages(struct drm_i915_gem_object *obj) 113 { 114 if (i915_gem_object_unbind(obj) == 0) 115 __i915_gem_object_put_pages(obj, I915_MM_SHRINKER); 116 return !i915_gem_object_has_pages(obj); 117 } 118 119 /** 120 * i915_gem_shrink - Shrink buffer object caches 121 * @dev_priv: i915 device 122 * @target: amount of memory to make available, in pages 123 * @nr_scanned: optional output for number of pages scanned (incremental) 124 * @flags: control flags for selecting cache types 125 * 126 * This function is the main interface to the shrinker. It will try to release 127 * up to @target pages of main memory backing storage from buffer objects. 128 * Selection of the specific caches can be done with @flags. This is e.g. useful 129 * when purgeable objects should be removed from caches preferentially. 130 * 131 * Note that it's not guaranteed that released amount is actually available as 132 * free system memory - the pages might still be in-used to due to other reasons 133 * (like cpu mmaps) or the mm core has reused them before we could grab them. 134 * Therefore code that needs to explicitly shrink buffer objects caches (e.g. to 135 * avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all(). 136 * 137 * Also note that any kind of pinning (both per-vma address space pins and 138 * backing storage pins at the buffer object level) result in the shrinker code 139 * having to skip the object. 140 * 141 * Returns: 142 * The number of pages of backing storage actually released. 143 */ 144 unsigned long 145 i915_gem_shrink(struct drm_i915_private *dev_priv, 146 unsigned long target, 147 unsigned long *nr_scanned, 148 unsigned flags) 149 { 150 const struct { 151 struct list_head *list; 152 unsigned int bit; 153 } phases[] = { 154 { &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND }, 155 { &dev_priv->mm.bound_list, I915_SHRINK_BOUND }, 156 { NULL, 0 }, 157 }, *phase; 158 unsigned long count = 0; 159 unsigned long scanned = 0; 160 bool unlock; 161 162 if (!shrinker_lock(dev_priv, &unlock)) 163 return 0; 164 165 /* 166 * When shrinking the active list, also consider active contexts. 167 * Active contexts are pinned until they are retired, and so can 168 * not be simply unbound to retire and unpin their pages. To shrink 169 * the contexts, we must wait until the gpu is idle. 170 * 171 * We don't care about errors here; if we cannot wait upon the GPU, 172 * we will free as much as we can and hope to get a second chance. 173 */ 174 if (flags & I915_SHRINK_ACTIVE) 175 i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED); 176 177 trace_i915_gem_shrink(dev_priv, target, flags); 178 i915_gem_retire_requests(dev_priv); 179 180 /* 181 * Unbinding of objects will require HW access; Let us not wake the 182 * device just to recover a little memory. If absolutely necessary, 183 * we will force the wake during oom-notifier. 184 */ 185 if ((flags & I915_SHRINK_BOUND) && 186 !intel_runtime_pm_get_if_in_use(dev_priv)) 187 flags &= ~I915_SHRINK_BOUND; 188 189 /* 190 * As we may completely rewrite the (un)bound list whilst unbinding 191 * (due to retiring requests) we have to strictly process only 192 * one element of the list at the time, and recheck the list 193 * on every iteration. 194 * 195 * In particular, we must hold a reference whilst removing the 196 * object as we may end up waiting for and/or retiring the objects. 197 * This might release the final reference (held by the active list) 198 * and result in the object being freed from under us. This is 199 * similar to the precautions the eviction code must take whilst 200 * removing objects. 201 * 202 * Also note that although these lists do not hold a reference to 203 * the object we can safely grab one here: The final object 204 * unreferencing and the bound_list are both protected by the 205 * dev->struct_mutex and so we won't ever be able to observe an 206 * object on the bound_list with a reference count equals 0. 207 */ 208 for (phase = phases; phase->list; phase++) { 209 struct list_head still_in_list; 210 struct drm_i915_gem_object *obj; 211 212 if ((flags & phase->bit) == 0) 213 continue; 214 215 INIT_LIST_HEAD(&still_in_list); 216 217 /* 218 * We serialize our access to unreferenced objects through 219 * the use of the struct_mutex. While the objects are not 220 * yet freed (due to RCU then a workqueue) we still want 221 * to be able to shrink their pages, so they remain on 222 * the unbound/bound list until actually freed. 223 */ 224 lockmgr(&dev_priv->mm.obj_lock, LK_EXCLUSIVE); 225 while (count < target && 226 (obj = list_first_entry_or_null(phase->list, 227 typeof(*obj), 228 mm.link))) { 229 list_move_tail(&obj->mm.link, &still_in_list); 230 231 if (flags & I915_SHRINK_PURGEABLE && 232 obj->mm.madv != I915_MADV_DONTNEED) 233 continue; 234 235 if (flags & I915_SHRINK_VMAPS && 236 !is_vmalloc_addr(obj->mm.mapping)) 237 continue; 238 239 if (!(flags & I915_SHRINK_ACTIVE) && 240 (i915_gem_object_is_active(obj) || 241 i915_gem_object_is_framebuffer(obj))) 242 continue; 243 244 if (!can_release_pages(obj)) 245 continue; 246 247 lockmgr(&dev_priv->mm.obj_lock, LK_RELEASE); 248 249 if (unsafe_drop_pages(obj)) { 250 /* May arrive from get_pages on another bo */ 251 mutex_lock_nested(&obj->mm.lock, 252 I915_MM_SHRINKER); 253 if (!i915_gem_object_has_pages(obj)) { 254 __i915_gem_object_invalidate(obj); 255 count += obj->base.size >> PAGE_SHIFT; 256 } 257 mutex_unlock(&obj->mm.lock); 258 } 259 scanned += obj->base.size >> PAGE_SHIFT; 260 261 lockmgr(&dev_priv->mm.obj_lock, LK_EXCLUSIVE); 262 } 263 list_splice_tail(&still_in_list, phase->list); 264 lockmgr(&dev_priv->mm.obj_lock, LK_RELEASE); 265 } 266 267 if (flags & I915_SHRINK_BOUND) 268 intel_runtime_pm_put(dev_priv); 269 270 i915_gem_retire_requests(dev_priv); 271 272 shrinker_unlock(dev_priv, unlock); 273 274 if (nr_scanned) 275 *nr_scanned += scanned; 276 return count; 277 } 278 279 /** 280 * i915_gem_shrink_all - Shrink buffer object caches completely 281 * @dev_priv: i915 device 282 * 283 * This is a simple wraper around i915_gem_shrink() to aggressively shrink all 284 * caches completely. It also first waits for and retires all outstanding 285 * requests to also be able to release backing storage for active objects. 286 * 287 * This should only be used in code to intentionally quiescent the gpu or as a 288 * last-ditch effort when memory seems to have run out. 289 * 290 * Returns: 291 * The number of pages of backing storage actually released. 292 */ 293 unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv) 294 { 295 unsigned long freed; 296 297 intel_runtime_pm_get(dev_priv); 298 freed = i915_gem_shrink(dev_priv, -1UL, NULL, 299 I915_SHRINK_BOUND | 300 I915_SHRINK_UNBOUND | 301 I915_SHRINK_ACTIVE); 302 intel_runtime_pm_put(dev_priv); 303 304 return freed; 305 } 306 307 static unsigned long 308 i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc) 309 { 310 #if 0 311 struct drm_i915_private *dev_priv = 312 container_of(shrinker, struct drm_i915_private, mm.shrinker); 313 struct drm_i915_gem_object *obj; 314 unsigned long count = 0; 315 316 spin_lock(&dev_priv->mm.obj_lock); 317 list_for_each_entry(obj, &dev_priv->mm.unbound_list, mm.link) 318 if (can_release_pages(obj)) 319 count += obj->base.size >> PAGE_SHIFT; 320 321 list_for_each_entry(obj, &dev_priv->mm.bound_list, mm.link) 322 if (!i915_gem_object_is_active(obj) && can_release_pages(obj)) 323 count += obj->base.size >> PAGE_SHIFT; 324 spin_unlock(&dev_priv->mm.obj_lock); 325 326 return count; 327 #endif 328 return 0; 329 } 330 331 static unsigned long 332 i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) 333 { 334 #if 0 335 struct drm_i915_private *dev_priv = 336 container_of(shrinker, struct drm_i915_private, mm.shrinker); 337 unsigned long freed; 338 bool unlock; 339 340 sc->nr_scanned = 0; 341 342 if (!shrinker_lock(dev_priv, &unlock)) 343 return SHRINK_STOP; 344 345 freed = i915_gem_shrink(dev_priv, 346 sc->nr_to_scan, 347 &sc->nr_scanned, 348 I915_SHRINK_BOUND | 349 I915_SHRINK_UNBOUND | 350 I915_SHRINK_PURGEABLE); 351 if (freed < sc->nr_to_scan) 352 freed += i915_gem_shrink(dev_priv, 353 sc->nr_to_scan - sc->nr_scanned, 354 &sc->nr_scanned, 355 I915_SHRINK_BOUND | 356 I915_SHRINK_UNBOUND); 357 if (freed < sc->nr_to_scan && current_is_kswapd()) { 358 intel_runtime_pm_get(dev_priv); 359 freed += i915_gem_shrink(dev_priv, 360 sc->nr_to_scan - sc->nr_scanned, 361 &sc->nr_scanned, 362 I915_SHRINK_ACTIVE | 363 I915_SHRINK_BOUND | 364 I915_SHRINK_UNBOUND); 365 intel_runtime_pm_put(dev_priv); 366 } 367 368 shrinker_unlock(dev_priv, unlock); 369 370 return freed; 371 #endif 372 return 0; 373 } 374 375 #if 0 376 static bool 377 shrinker_lock_uninterruptible(struct drm_i915_private *dev_priv, bool *unlock, 378 int timeout_ms) 379 { 380 unsigned long timeout = jiffies + msecs_to_jiffies_timeout(timeout_ms); 381 382 do { 383 if (i915_gem_wait_for_idle(dev_priv, 0) == 0 && 384 shrinker_lock(dev_priv, unlock)) 385 break; 386 387 schedule_timeout_killable(1); 388 if (fatal_signal_pending(current)) 389 return false; 390 391 if (time_after(jiffies, timeout)) { 392 pr_err("Unable to lock GPU to purge memory.\n"); 393 return false; 394 } 395 } while (1); 396 397 return true; 398 } 399 400 static int 401 i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr) 402 { 403 struct drm_i915_private *dev_priv = 404 container_of(nb, struct drm_i915_private, mm.oom_notifier); 405 struct drm_i915_gem_object *obj; 406 unsigned long unevictable, bound, unbound, freed_pages; 407 408 freed_pages = i915_gem_shrink_all(dev_priv); 409 410 /* Because we may be allocating inside our own driver, we cannot 411 * assert that there are no objects with pinned pages that are not 412 * being pointed to by hardware. 413 */ 414 unbound = bound = unevictable = 0; 415 spin_lock(&dev_priv->mm.obj_lock); 416 list_for_each_entry(obj, &dev_priv->mm.unbound_list, mm.link) { 417 if (!can_release_pages(obj)) 418 unevictable += obj->base.size >> PAGE_SHIFT; 419 else 420 unbound += obj->base.size >> PAGE_SHIFT; 421 } 422 list_for_each_entry(obj, &dev_priv->mm.bound_list, mm.link) { 423 if (!can_release_pages(obj)) 424 unevictable += obj->base.size >> PAGE_SHIFT; 425 else 426 bound += obj->base.size >> PAGE_SHIFT; 427 } 428 spin_unlock(&dev_priv->mm.obj_lock); 429 430 if (freed_pages || unbound || bound) 431 pr_info("Purging GPU memory, %lu pages freed, " 432 "%lu pages still pinned.\n", 433 freed_pages, unevictable); 434 if (unbound || bound) 435 pr_err("%lu and %lu pages still available in the " 436 "bound and unbound GPU page lists.\n", 437 bound, unbound); 438 439 *(unsigned long *)ptr += freed_pages; 440 return NOTIFY_DONE; 441 } 442 443 static int 444 i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr) 445 { 446 struct drm_i915_private *dev_priv = 447 container_of(nb, struct drm_i915_private, mm.vmap_notifier); 448 struct i915_vma *vma, *next; 449 unsigned long freed_pages = 0; 450 bool unlock; 451 int ret; 452 453 if (!shrinker_lock_uninterruptible(dev_priv, &unlock, 5000)) 454 return NOTIFY_DONE; 455 456 /* Force everything onto the inactive lists */ 457 ret = i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED); 458 if (ret) 459 goto out; 460 461 intel_runtime_pm_get(dev_priv); 462 freed_pages += i915_gem_shrink(dev_priv, -1UL, NULL, 463 I915_SHRINK_BOUND | 464 I915_SHRINK_UNBOUND | 465 I915_SHRINK_ACTIVE | 466 I915_SHRINK_VMAPS); 467 intel_runtime_pm_put(dev_priv); 468 469 /* We also want to clear any cached iomaps as they wrap vmap */ 470 list_for_each_entry_safe(vma, next, 471 &dev_priv->ggtt.base.inactive_list, vm_link) { 472 unsigned long count = vma->node.size >> PAGE_SHIFT; 473 if (vma->iomap && i915_vma_unbind(vma) == 0) 474 freed_pages += count; 475 } 476 477 out: 478 shrinker_unlock(dev_priv, unlock); 479 480 *(unsigned long *)ptr += freed_pages; 481 return NOTIFY_DONE; 482 } 483 #endif 484 485 /** 486 * i915_gem_shrinker_init - Initialize i915 shrinker 487 * @dev_priv: i915 device 488 * 489 * This function registers and sets up the i915 shrinker and OOM handler. 490 */ 491 void i915_gem_shrinker_init(struct drm_i915_private *dev_priv) 492 { 493 dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan; 494 dev_priv->mm.shrinker.count_objects = i915_gem_shrinker_count; 495 dev_priv->mm.shrinker.seeks = DEFAULT_SEEKS; 496 #if 0 497 WARN_ON(register_shrinker(&dev_priv->mm.shrinker)); 498 499 dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom; 500 WARN_ON(register_oom_notifier(&dev_priv->mm.oom_notifier)); 501 502 dev_priv->mm.vmap_notifier.notifier_call = i915_gem_shrinker_vmap; 503 WARN_ON(register_vmap_purge_notifier(&dev_priv->mm.vmap_notifier)); 504 #endif 505 } 506 507 /** 508 * i915_gem_shrinker_cleanup - Clean up i915 shrinker 509 * @dev_priv: i915 device 510 * 511 * This function unregisters the i915 shrinker and OOM handler. 512 */ 513 void i915_gem_shrinker_cleanup(struct drm_i915_private *dev_priv) 514 { 515 #if 0 516 WARN_ON(unregister_vmap_purge_notifier(&dev_priv->mm.vmap_notifier)); 517 WARN_ON(unregister_oom_notifier(&dev_priv->mm.oom_notifier)); 518 unregister_shrinker(&dev_priv->mm.shrinker); 519 #endif 520 } 521