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 "gem/i915_gem_context.h" 32 33 #include "i915_drv.h" 34 #include "i915_trace.h" 35 36 I915_SELFTEST_DECLARE(static struct igt_evict_ctl { 37 bool fail_if_busy:1; 38 } igt_evict_ctl;) 39 40 static int ggtt_flush(struct drm_i915_private *i915) 41 { 42 /* 43 * Not everything in the GGTT is tracked via vma (otherwise we 44 * could evict as required with minimal stalling) so we are forced 45 * to idle the GPU and explicitly retire outstanding requests in 46 * the hopes that we can then remove contexts and the like only 47 * bound by their active reference. 48 */ 49 return i915_gem_wait_for_idle(i915, 50 I915_WAIT_INTERRUPTIBLE | 51 I915_WAIT_LOCKED, 52 MAX_SCHEDULE_TIMEOUT); 53 } 54 55 static bool 56 mark_free(struct drm_mm_scan *scan, 57 struct i915_vma *vma, 58 unsigned int flags, 59 struct list_head *unwind) 60 { 61 if (i915_vma_is_pinned(vma)) 62 return false; 63 64 list_add(&vma->evict_link, unwind); 65 return drm_mm_scan_add_block(scan, &vma->node); 66 } 67 68 /** 69 * i915_gem_evict_something - Evict vmas to make room for binding a new one 70 * @vm: address space to evict from 71 * @min_size: size of the desired free space 72 * @alignment: alignment constraint of the desired free space 73 * @cache_level: cache_level for the desired space 74 * @start: start (inclusive) of the range from which to evict objects 75 * @end: end (exclusive) of the range from which to evict objects 76 * @flags: additional flags to control the eviction algorithm 77 * 78 * This function will try to evict vmas until a free space satisfying the 79 * requirements is found. Callers must check first whether any such hole exists 80 * already before calling this function. 81 * 82 * This function is used by the object/vma binding code. 83 * 84 * Since this function is only used to free up virtual address space it only 85 * ignores pinned vmas, and not object where the backing storage itself is 86 * pinned. Hence obj->pages_pin_count does not protect against eviction. 87 * 88 * To clarify: This is for freeing up virtual address space, not for freeing 89 * memory in e.g. the shrinker. 90 */ 91 int 92 i915_gem_evict_something(struct i915_address_space *vm, 93 u64 min_size, u64 alignment, 94 unsigned cache_level, 95 u64 start, u64 end, 96 unsigned flags) 97 { 98 struct drm_i915_private *dev_priv = vm->i915; 99 struct drm_mm_scan scan; 100 struct list_head eviction_list; 101 struct i915_vma *vma, *next; 102 struct drm_mm_node *node; 103 enum drm_mm_insert_mode mode; 104 struct i915_vma *active; 105 int ret; 106 107 lockdep_assert_held(&vm->i915->drm.struct_mutex); 108 trace_i915_gem_evict(vm, min_size, alignment, flags); 109 110 /* 111 * The goal is to evict objects and amalgamate space in rough LRU order. 112 * Since both active and inactive objects reside on the same list, 113 * in a mix of creation and last scanned order, as we process the list 114 * we sort it into inactive/active, which keeps the active portion 115 * in a rough MRU order. 116 * 117 * The retirement sequence is thus: 118 * 1. Inactive objects (already retired, random order) 119 * 2. Active objects (will stall on unbinding, oldest scanned first) 120 */ 121 mode = DRM_MM_INSERT_BEST; 122 if (flags & PIN_HIGH) 123 mode = DRM_MM_INSERT_HIGH; 124 if (flags & PIN_MAPPABLE) 125 mode = DRM_MM_INSERT_LOW; 126 drm_mm_scan_init_with_range(&scan, &vm->mm, 127 min_size, alignment, cache_level, 128 start, end, mode); 129 130 /* 131 * Retire before we search the active list. Although we have 132 * reasonable accuracy in our retirement lists, we may have 133 * a stray pin (preventing eviction) that can only be resolved by 134 * retiring. 135 */ 136 if (!(flags & PIN_NONBLOCK)) 137 i915_retire_requests(dev_priv); 138 139 search_again: 140 active = NULL; 141 INIT_LIST_HEAD(&eviction_list); 142 list_for_each_entry_safe(vma, next, &vm->bound_list, vm_link) { 143 /* 144 * We keep this list in a rough least-recently scanned order 145 * of active elements (inactive elements are cheap to reap). 146 * New entries are added to the end, and we move anything we 147 * scan to the end. The assumption is that the working set 148 * of applications is either steady state (and thanks to the 149 * userspace bo cache it almost always is) or volatile and 150 * frequently replaced after a frame, which are self-evicting! 151 * Given that assumption, the MRU order of the scan list is 152 * fairly static, and keeping it in least-recently scan order 153 * is suitable. 154 * 155 * To notice when we complete one full cycle, we record the 156 * first active element seen, before moving it to the tail. 157 */ 158 if (i915_vma_is_active(vma)) { 159 if (vma == active) { 160 if (flags & PIN_NONBLOCK) 161 break; 162 163 active = ERR_PTR(-EAGAIN); 164 } 165 166 if (active != ERR_PTR(-EAGAIN)) { 167 if (!active) 168 active = vma; 169 170 list_move_tail(&vma->vm_link, &vm->bound_list); 171 continue; 172 } 173 } 174 175 if (mark_free(&scan, vma, flags, &eviction_list)) 176 goto found; 177 } 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 (I915_SELFTEST_ONLY(igt_evict_ctl.fail_if_busy)) 208 return -EBUSY; 209 210 ret = ggtt_flush(dev_priv); 211 if (ret) 212 return ret; 213 214 cond_resched(); 215 216 flags |= PIN_NONBLOCK; 217 goto search_again; 218 219 found: 220 /* drm_mm doesn't allow any other other operations while 221 * scanning, therefore store to-be-evicted objects on a 222 * temporary list and take a reference for all before 223 * calling unbind (which may remove the active reference 224 * of any of our objects, thus corrupting the list). 225 */ 226 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 227 if (drm_mm_scan_remove_block(&scan, &vma->node)) 228 __i915_vma_pin(vma); 229 else 230 list_del(&vma->evict_link); 231 } 232 233 /* Unbinding will emit any required flushes */ 234 ret = 0; 235 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 236 __i915_vma_unpin(vma); 237 if (ret == 0) 238 ret = i915_vma_unbind(vma); 239 } 240 241 while (ret == 0 && (node = drm_mm_scan_color_evict(&scan))) { 242 vma = container_of(node, struct i915_vma, node); 243 ret = i915_vma_unbind(vma); 244 } 245 246 return ret; 247 } 248 249 /** 250 * i915_gem_evict_for_vma - Evict vmas to make room for binding a new one 251 * @vm: address space to evict from 252 * @target: range (and color) to evict for 253 * @flags: additional flags to control the eviction algorithm 254 * 255 * This function will try to evict vmas that overlap the target node. 256 * 257 * To clarify: This is for freeing up virtual address space, not for freeing 258 * memory in e.g. the shrinker. 259 */ 260 int i915_gem_evict_for_node(struct i915_address_space *vm, 261 struct drm_mm_node *target, 262 unsigned int flags) 263 { 264 LIST_HEAD(eviction_list); 265 struct drm_mm_node *node; 266 u64 start = target->start; 267 u64 end = start + target->size; 268 struct i915_vma *vma, *next; 269 bool check_color; 270 int ret = 0; 271 272 lockdep_assert_held(&vm->i915->drm.struct_mutex); 273 GEM_BUG_ON(!IS_ALIGNED(start, I915_GTT_PAGE_SIZE)); 274 GEM_BUG_ON(!IS_ALIGNED(end, I915_GTT_PAGE_SIZE)); 275 276 trace_i915_gem_evict_node(vm, target, flags); 277 278 /* Retire before we search the active list. Although we have 279 * reasonable accuracy in our retirement lists, we may have 280 * a stray pin (preventing eviction) that can only be resolved by 281 * retiring. 282 */ 283 if (!(flags & PIN_NONBLOCK)) 284 i915_retire_requests(vm->i915); 285 286 check_color = vm->mm.color_adjust; 287 if (check_color) { 288 /* Expand search to cover neighbouring guard pages (or lack!) */ 289 if (start) 290 start -= I915_GTT_PAGE_SIZE; 291 292 /* Always look at the page afterwards to avoid the end-of-GTT */ 293 end += I915_GTT_PAGE_SIZE; 294 } 295 GEM_BUG_ON(start >= end); 296 297 drm_mm_for_each_node_in_range(node, &vm->mm, start, end) { 298 /* If we find any non-objects (!vma), we cannot evict them */ 299 if (node->color == I915_COLOR_UNEVICTABLE) { 300 ret = -ENOSPC; 301 break; 302 } 303 304 GEM_BUG_ON(!node->allocated); 305 vma = container_of(node, typeof(*vma), node); 306 307 /* If we are using coloring to insert guard pages between 308 * different cache domains within the address space, we have 309 * to check whether the objects on either side of our range 310 * abutt and conflict. If they are in conflict, then we evict 311 * those as well to make room for our guard pages. 312 */ 313 if (check_color) { 314 if (node->start + node->size == target->start) { 315 if (node->color == target->color) 316 continue; 317 } 318 if (node->start == target->start + target->size) { 319 if (node->color == target->color) 320 continue; 321 } 322 } 323 324 if (flags & PIN_NONBLOCK && 325 (i915_vma_is_pinned(vma) || i915_vma_is_active(vma))) { 326 ret = -ENOSPC; 327 break; 328 } 329 330 /* Overlap of objects in the same batch? */ 331 if (i915_vma_is_pinned(vma)) { 332 ret = -ENOSPC; 333 if (vma->exec_flags && 334 *vma->exec_flags & EXEC_OBJECT_PINNED) 335 ret = -EINVAL; 336 break; 337 } 338 339 /* Never show fear in the face of dragons! 340 * 341 * We cannot directly remove this node from within this 342 * iterator and as with i915_gem_evict_something() we employ 343 * the vma pin_count in order to prevent the action of 344 * unbinding one vma from freeing (by dropping its active 345 * reference) another in our eviction list. 346 */ 347 __i915_vma_pin(vma); 348 list_add(&vma->evict_link, &eviction_list); 349 } 350 351 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 352 __i915_vma_unpin(vma); 353 if (ret == 0) 354 ret = i915_vma_unbind(vma); 355 } 356 357 return ret; 358 } 359 360 /** 361 * i915_gem_evict_vm - Evict all idle vmas from a vm 362 * @vm: Address space to cleanse 363 * 364 * This function evicts all vmas from a vm. 365 * 366 * This is used by the execbuf code as a last-ditch effort to defragment the 367 * address space. 368 * 369 * To clarify: This is for freeing up virtual address space, not for freeing 370 * memory in e.g. the shrinker. 371 */ 372 int i915_gem_evict_vm(struct i915_address_space *vm) 373 { 374 struct list_head eviction_list; 375 struct i915_vma *vma, *next; 376 int ret; 377 378 lockdep_assert_held(&vm->i915->drm.struct_mutex); 379 trace_i915_gem_evict_vm(vm); 380 381 /* Switch back to the default context in order to unpin 382 * the existing context objects. However, such objects only 383 * pin themselves inside the global GTT and performing the 384 * switch otherwise is ineffective. 385 */ 386 if (i915_is_ggtt(vm)) { 387 ret = ggtt_flush(vm->i915); 388 if (ret) 389 return ret; 390 } 391 392 INIT_LIST_HEAD(&eviction_list); 393 mutex_lock(&vm->mutex); 394 list_for_each_entry(vma, &vm->bound_list, vm_link) { 395 if (i915_vma_is_pinned(vma)) 396 continue; 397 398 __i915_vma_pin(vma); 399 list_add(&vma->evict_link, &eviction_list); 400 } 401 mutex_unlock(&vm->mutex); 402 403 ret = 0; 404 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 405 __i915_vma_unpin(vma); 406 if (ret == 0) 407 ret = i915_vma_unbind(vma); 408 } 409 return ret; 410 } 411 412 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) 413 #include "selftests/i915_gem_evict.c" 414 #endif 415