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/i915_drm.h> 30 31 #include "i915_drv.h" 32 #include "intel_drv.h" 33 #include "i915_trace.h" 34 35 I915_SELFTEST_DECLARE(static struct igt_evict_ctl { 36 bool fail_if_busy:1; 37 } igt_evict_ctl;) 38 39 static bool ggtt_is_idle(struct drm_i915_private *i915) 40 { 41 return !i915->gt.active_requests; 42 } 43 44 static int ggtt_flush(struct drm_i915_private *i915) 45 { 46 int err; 47 48 /* 49 * Not everything in the GGTT is tracked via vma (otherwise we 50 * could evict as required with minimal stalling) so we are forced 51 * to idle the GPU and explicitly retire outstanding requests in 52 * the hopes that we can then remove contexts and the like only 53 * bound by their active reference. 54 */ 55 err = i915_gem_switch_to_kernel_context(i915, i915->gt.active_engines); 56 if (err) 57 return err; 58 59 err = i915_gem_wait_for_idle(i915, 60 I915_WAIT_INTERRUPTIBLE | 61 I915_WAIT_LOCKED, 62 MAX_SCHEDULE_TIMEOUT); 63 if (err) 64 return err; 65 66 GEM_BUG_ON(!ggtt_is_idle(i915)); 67 return 0; 68 } 69 70 static bool 71 mark_free(struct drm_mm_scan *scan, 72 struct i915_vma *vma, 73 unsigned int flags, 74 struct list_head *unwind) 75 { 76 if (i915_vma_is_pinned(vma)) 77 return false; 78 79 if (flags & PIN_NONFAULT && i915_vma_has_userfault(vma)) 80 return false; 81 82 list_add(&vma->evict_link, unwind); 83 return drm_mm_scan_add_block(scan, &vma->node); 84 } 85 86 /** 87 * i915_gem_evict_something - Evict vmas to make room for binding a new one 88 * @vm: address space to evict from 89 * @min_size: size of the desired free space 90 * @alignment: alignment constraint of the desired free space 91 * @cache_level: cache_level for the desired space 92 * @start: start (inclusive) of the range from which to evict objects 93 * @end: end (exclusive) of the range from which to evict objects 94 * @flags: additional flags to control the eviction algorithm 95 * 96 * This function will try to evict vmas until a free space satisfying the 97 * requirements is found. Callers must check first whether any such hole exists 98 * already before calling this function. 99 * 100 * This function is used by the object/vma binding code. 101 * 102 * Since this function is only used to free up virtual address space it only 103 * ignores pinned vmas, and not object where the backing storage itself is 104 * pinned. Hence obj->pages_pin_count does not protect against eviction. 105 * 106 * To clarify: This is for freeing up virtual address space, not for freeing 107 * memory in e.g. the shrinker. 108 */ 109 int 110 i915_gem_evict_something(struct i915_address_space *vm, 111 u64 min_size, u64 alignment, 112 unsigned cache_level, 113 u64 start, u64 end, 114 unsigned flags) 115 { 116 struct drm_i915_private *dev_priv = vm->i915; 117 struct drm_mm_scan scan; 118 struct list_head eviction_list; 119 struct i915_vma *vma, *next; 120 struct drm_mm_node *node; 121 enum drm_mm_insert_mode mode; 122 struct i915_vma *active; 123 int ret; 124 125 lockdep_assert_held(&vm->i915->drm.struct_mutex); 126 trace_i915_gem_evict(vm, min_size, alignment, flags); 127 128 /* 129 * The goal is to evict objects and amalgamate space in rough LRU order. 130 * Since both active and inactive objects reside on the same list, 131 * in a mix of creation and last scanned order, as we process the list 132 * we sort it into inactive/active, which keeps the active portion 133 * in a rough MRU order. 134 * 135 * The retirement sequence is thus: 136 * 1. Inactive objects (already retired, random order) 137 * 2. Active objects (will stall on unbinding, oldest scanned first) 138 */ 139 mode = DRM_MM_INSERT_BEST; 140 if (flags & PIN_HIGH) 141 mode = DRM_MM_INSERT_HIGH; 142 if (flags & PIN_MAPPABLE) 143 mode = DRM_MM_INSERT_LOW; 144 drm_mm_scan_init_with_range(&scan, &vm->mm, 145 min_size, alignment, cache_level, 146 start, end, mode); 147 148 /* 149 * Retire before we search the active list. Although we have 150 * reasonable accuracy in our retirement lists, we may have 151 * a stray pin (preventing eviction) that can only be resolved by 152 * retiring. 153 */ 154 if (!(flags & PIN_NONBLOCK)) 155 i915_retire_requests(dev_priv); 156 157 search_again: 158 active = NULL; 159 INIT_LIST_HEAD(&eviction_list); 160 list_for_each_entry_safe(vma, next, &vm->bound_list, vm_link) { 161 /* 162 * We keep this list in a rough least-recently scanned order 163 * of active elements (inactive elements are cheap to reap). 164 * New entries are added to the end, and we move anything we 165 * scan to the end. The assumption is that the working set 166 * of applications is either steady state (and thanks to the 167 * userspace bo cache it almost always is) or volatile and 168 * frequently replaced after a frame, which are self-evicting! 169 * Given that assumption, the MRU order of the scan list is 170 * fairly static, and keeping it in least-recently scan order 171 * is suitable. 172 * 173 * To notice when we complete one full cycle, we record the 174 * first active element seen, before moving it to the tail. 175 */ 176 if (i915_vma_is_active(vma)) { 177 if (vma == active) { 178 if (flags & PIN_NONBLOCK) 179 break; 180 181 active = ERR_PTR(-EAGAIN); 182 } 183 184 if (active != ERR_PTR(-EAGAIN)) { 185 if (!active) 186 active = vma; 187 188 list_move_tail(&vma->vm_link, &vm->bound_list); 189 continue; 190 } 191 } 192 193 if (mark_free(&scan, vma, flags, &eviction_list)) 194 goto found; 195 } 196 197 /* Nothing found, clean up and bail out! */ 198 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 199 ret = drm_mm_scan_remove_block(&scan, &vma->node); 200 BUG_ON(ret); 201 } 202 203 /* 204 * Can we unpin some objects such as idle hw contents, 205 * or pending flips? But since only the GGTT has global entries 206 * such as scanouts, rinbuffers and contexts, we can skip the 207 * purge when inspecting per-process local address spaces. 208 */ 209 if (!i915_is_ggtt(vm) || flags & PIN_NONBLOCK) 210 return -ENOSPC; 211 212 /* 213 * Not everything in the GGTT is tracked via VMA using 214 * i915_vma_move_to_active(), otherwise we could evict as required 215 * with minimal stalling. Instead we are forced to idle the GPU and 216 * explicitly retire outstanding requests which will then remove 217 * the pinning for active objects such as contexts and ring, 218 * enabling us to evict them on the next iteration. 219 * 220 * To ensure that all user contexts are evictable, we perform 221 * a switch to the perma-pinned kernel context. This all also gives 222 * us a termination condition, when the last retired context is 223 * the kernel's there is no more we can evict. 224 */ 225 if (!ggtt_is_idle(dev_priv)) { 226 if (I915_SELFTEST_ONLY(igt_evict_ctl.fail_if_busy)) 227 return -EBUSY; 228 229 ret = ggtt_flush(dev_priv); 230 if (ret) 231 return ret; 232 233 cond_resched(); 234 goto search_again; 235 } 236 237 /* 238 * If we still have pending pageflip completions, drop 239 * back to userspace to give our workqueues time to 240 * acquire our locks and unpin the old scanouts. 241 */ 242 return intel_has_pending_fb_unpin(dev_priv) ? -EAGAIN : -ENOSPC; 243 244 found: 245 /* drm_mm doesn't allow any other other operations while 246 * scanning, therefore store to-be-evicted objects on a 247 * temporary list and take a reference for all before 248 * calling unbind (which may remove the active reference 249 * of any of our objects, thus corrupting the list). 250 */ 251 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 252 if (drm_mm_scan_remove_block(&scan, &vma->node)) 253 __i915_vma_pin(vma); 254 else 255 list_del(&vma->evict_link); 256 } 257 258 /* Unbinding will emit any required flushes */ 259 ret = 0; 260 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 261 __i915_vma_unpin(vma); 262 if (ret == 0) 263 ret = i915_vma_unbind(vma); 264 } 265 266 while (ret == 0 && (node = drm_mm_scan_color_evict(&scan))) { 267 vma = container_of(node, struct i915_vma, node); 268 ret = i915_vma_unbind(vma); 269 } 270 271 return ret; 272 } 273 274 /** 275 * i915_gem_evict_for_vma - Evict vmas to make room for binding a new one 276 * @vm: address space to evict from 277 * @target: range (and color) to evict for 278 * @flags: additional flags to control the eviction algorithm 279 * 280 * This function will try to evict vmas that overlap the target node. 281 * 282 * To clarify: This is for freeing up virtual address space, not for freeing 283 * memory in e.g. the shrinker. 284 */ 285 int i915_gem_evict_for_node(struct i915_address_space *vm, 286 struct drm_mm_node *target, 287 unsigned int flags) 288 { 289 LIST_HEAD(eviction_list); 290 struct drm_mm_node *node; 291 u64 start = target->start; 292 u64 end = start + target->size; 293 struct i915_vma *vma, *next; 294 bool check_color; 295 int ret = 0; 296 297 lockdep_assert_held(&vm->i915->drm.struct_mutex); 298 GEM_BUG_ON(!IS_ALIGNED(start, I915_GTT_PAGE_SIZE)); 299 GEM_BUG_ON(!IS_ALIGNED(end, I915_GTT_PAGE_SIZE)); 300 301 trace_i915_gem_evict_node(vm, target, flags); 302 303 /* Retire before we search the active list. Although we have 304 * reasonable accuracy in our retirement lists, we may have 305 * a stray pin (preventing eviction) that can only be resolved by 306 * retiring. 307 */ 308 if (!(flags & PIN_NONBLOCK)) 309 i915_retire_requests(vm->i915); 310 311 check_color = vm->mm.color_adjust; 312 if (check_color) { 313 /* Expand search to cover neighbouring guard pages (or lack!) */ 314 if (start) 315 start -= I915_GTT_PAGE_SIZE; 316 317 /* Always look at the page afterwards to avoid the end-of-GTT */ 318 end += I915_GTT_PAGE_SIZE; 319 } 320 GEM_BUG_ON(start >= end); 321 322 drm_mm_for_each_node_in_range(node, &vm->mm, start, end) { 323 /* If we find any non-objects (!vma), we cannot evict them */ 324 if (node->color == I915_COLOR_UNEVICTABLE) { 325 ret = -ENOSPC; 326 break; 327 } 328 329 GEM_BUG_ON(!node->allocated); 330 vma = container_of(node, typeof(*vma), node); 331 332 /* If we are using coloring to insert guard pages between 333 * different cache domains within the address space, we have 334 * to check whether the objects on either side of our range 335 * abutt and conflict. If they are in conflict, then we evict 336 * those as well to make room for our guard pages. 337 */ 338 if (check_color) { 339 if (node->start + node->size == target->start) { 340 if (node->color == target->color) 341 continue; 342 } 343 if (node->start == target->start + target->size) { 344 if (node->color == target->color) 345 continue; 346 } 347 } 348 349 if (flags & PIN_NONBLOCK && 350 (i915_vma_is_pinned(vma) || i915_vma_is_active(vma))) { 351 ret = -ENOSPC; 352 break; 353 } 354 355 if (flags & PIN_NONFAULT && i915_vma_has_userfault(vma)) { 356 ret = -ENOSPC; 357 break; 358 } 359 360 /* Overlap of objects in the same batch? */ 361 if (i915_vma_is_pinned(vma)) { 362 ret = -ENOSPC; 363 if (vma->exec_flags && 364 *vma->exec_flags & EXEC_OBJECT_PINNED) 365 ret = -EINVAL; 366 break; 367 } 368 369 /* Never show fear in the face of dragons! 370 * 371 * We cannot directly remove this node from within this 372 * iterator and as with i915_gem_evict_something() we employ 373 * the vma pin_count in order to prevent the action of 374 * unbinding one vma from freeing (by dropping its active 375 * reference) another in our eviction list. 376 */ 377 __i915_vma_pin(vma); 378 list_add(&vma->evict_link, &eviction_list); 379 } 380 381 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 382 __i915_vma_unpin(vma); 383 if (ret == 0) 384 ret = i915_vma_unbind(vma); 385 } 386 387 return ret; 388 } 389 390 /** 391 * i915_gem_evict_vm - Evict all idle vmas from a vm 392 * @vm: Address space to cleanse 393 * 394 * This function evicts all vmas from a vm. 395 * 396 * This is used by the execbuf code as a last-ditch effort to defragment the 397 * address space. 398 * 399 * To clarify: This is for freeing up virtual address space, not for freeing 400 * memory in e.g. the shrinker. 401 */ 402 int i915_gem_evict_vm(struct i915_address_space *vm) 403 { 404 struct list_head eviction_list; 405 struct i915_vma *vma, *next; 406 int ret; 407 408 lockdep_assert_held(&vm->i915->drm.struct_mutex); 409 trace_i915_gem_evict_vm(vm); 410 411 /* Switch back to the default context in order to unpin 412 * the existing context objects. However, such objects only 413 * pin themselves inside the global GTT and performing the 414 * switch otherwise is ineffective. 415 */ 416 if (i915_is_ggtt(vm)) { 417 ret = ggtt_flush(vm->i915); 418 if (ret) 419 return ret; 420 } 421 422 INIT_LIST_HEAD(&eviction_list); 423 mutex_lock(&vm->mutex); 424 list_for_each_entry(vma, &vm->bound_list, vm_link) { 425 if (i915_vma_is_pinned(vma)) 426 continue; 427 428 __i915_vma_pin(vma); 429 list_add(&vma->evict_link, &eviction_list); 430 } 431 mutex_unlock(&vm->mutex); 432 433 ret = 0; 434 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 435 __i915_vma_unpin(vma); 436 if (ret == 0) 437 ret = i915_vma_unbind(vma); 438 } 439 return ret; 440 } 441 442 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) 443 #include "selftests/i915_gem_evict.c" 444 #endif 445