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 "gem/i915_gem_context.h" 30 #include "gt/intel_gt.h" 31 #include "gt/intel_gt_requests.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 intel_gt *gt) 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 intel_gt_wait_for_idle(gt, MAX_SCHEDULE_TIMEOUT); 50 } 51 52 static bool 53 mark_free(struct drm_mm_scan *scan, 54 struct i915_vma *vma, 55 unsigned int flags, 56 struct list_head *unwind) 57 { 58 if (i915_vma_is_pinned(vma)) 59 return false; 60 61 list_add(&vma->evict_link, unwind); 62 return drm_mm_scan_add_block(scan, &vma->node); 63 } 64 65 static bool defer_evict(struct i915_vma *vma) 66 { 67 if (i915_vma_is_active(vma)) 68 return true; 69 70 if (i915_vma_is_scanout(vma)) 71 return true; 72 73 return false; 74 } 75 76 /** 77 * i915_gem_evict_something - Evict vmas to make room for binding a new one 78 * @vm: address space to evict from 79 * @min_size: size of the desired free space 80 * @alignment: alignment constraint of the desired free space 81 * @color: color for the desired space 82 * @start: start (inclusive) of the range from which to evict objects 83 * @end: end (exclusive) of the range from which to evict objects 84 * @flags: additional flags to control the eviction algorithm 85 * 86 * This function will try to evict vmas until a free space satisfying the 87 * requirements is found. Callers must check first whether any such hole exists 88 * already before calling this function. 89 * 90 * This function is used by the object/vma binding code. 91 * 92 * Since this function is only used to free up virtual address space it only 93 * ignores pinned vmas, and not object where the backing storage itself is 94 * pinned. Hence obj->pages_pin_count does not protect against eviction. 95 * 96 * To clarify: This is for freeing up virtual address space, not for freeing 97 * memory in e.g. the shrinker. 98 */ 99 int 100 i915_gem_evict_something(struct i915_address_space *vm, 101 u64 min_size, u64 alignment, 102 unsigned long color, 103 u64 start, u64 end, 104 unsigned flags) 105 { 106 struct drm_mm_scan scan; 107 struct list_head eviction_list; 108 struct i915_vma *vma, *next; 109 struct drm_mm_node *node; 110 enum drm_mm_insert_mode mode; 111 struct i915_vma *active; 112 int ret; 113 114 lockdep_assert_held(&vm->mutex); 115 trace_i915_gem_evict(vm, min_size, alignment, flags); 116 117 /* 118 * The goal is to evict objects and amalgamate space in rough LRU order. 119 * Since both active and inactive objects reside on the same list, 120 * in a mix of creation and last scanned order, as we process the list 121 * we sort it into inactive/active, which keeps the active portion 122 * in a rough MRU order. 123 * 124 * The retirement sequence is thus: 125 * 1. Inactive objects (already retired, random order) 126 * 2. Active objects (will stall on unbinding, oldest scanned first) 127 */ 128 mode = DRM_MM_INSERT_BEST; 129 if (flags & PIN_HIGH) 130 mode = DRM_MM_INSERT_HIGH; 131 if (flags & PIN_MAPPABLE) 132 mode = DRM_MM_INSERT_LOW; 133 drm_mm_scan_init_with_range(&scan, &vm->mm, 134 min_size, alignment, color, 135 start, end, mode); 136 137 intel_gt_retire_requests(vm->gt); 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 if (vma == active) { /* now seen this vma twice */ 144 if (flags & PIN_NONBLOCK) 145 break; 146 147 active = ERR_PTR(-EAGAIN); 148 } 149 150 /* 151 * We keep this list in a rough least-recently scanned order 152 * of active elements (inactive elements are cheap to reap). 153 * New entries are added to the end, and we move anything we 154 * scan to the end. The assumption is that the working set 155 * of applications is either steady state (and thanks to the 156 * userspace bo cache it almost always is) or volatile and 157 * frequently replaced after a frame, which are self-evicting! 158 * Given that assumption, the MRU order of the scan list is 159 * fairly static, and keeping it in least-recently scan order 160 * is suitable. 161 * 162 * To notice when we complete one full cycle, we record the 163 * first active element seen, before moving it to the tail. 164 */ 165 if (active != ERR_PTR(-EAGAIN) && defer_evict(vma)) { 166 if (!active) 167 active = vma; 168 169 list_move_tail(&vma->vm_link, &vm->bound_list); 170 continue; 171 } 172 173 if (mark_free(&scan, vma, flags, &eviction_list)) 174 goto found; 175 } 176 177 /* Nothing found, clean up and bail out! */ 178 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 179 ret = drm_mm_scan_remove_block(&scan, &vma->node); 180 BUG_ON(ret); 181 } 182 183 /* 184 * Can we unpin some objects such as idle hw contents, 185 * or pending flips? But since only the GGTT has global entries 186 * such as scanouts, rinbuffers and contexts, we can skip the 187 * purge when inspecting per-process local address spaces. 188 */ 189 if (!i915_is_ggtt(vm) || flags & PIN_NONBLOCK) 190 return -ENOSPC; 191 192 /* 193 * Not everything in the GGTT is tracked via VMA using 194 * i915_vma_move_to_active(), otherwise we could evict as required 195 * with minimal stalling. Instead we are forced to idle the GPU and 196 * explicitly retire outstanding requests which will then remove 197 * the pinning for active objects such as contexts and ring, 198 * enabling us to evict them on the next iteration. 199 * 200 * To ensure that all user contexts are evictable, we perform 201 * a switch to the perma-pinned kernel context. This all also gives 202 * us a termination condition, when the last retired context is 203 * the kernel's there is no more we can evict. 204 */ 205 if (I915_SELFTEST_ONLY(igt_evict_ctl.fail_if_busy)) 206 return -EBUSY; 207 208 ret = ggtt_flush(vm->gt); 209 if (ret) 210 return ret; 211 212 cond_resched(); 213 214 flags |= PIN_NONBLOCK; 215 goto search_again; 216 217 found: 218 /* drm_mm doesn't allow any other other operations while 219 * scanning, therefore store to-be-evicted objects on a 220 * temporary list and take a reference for all before 221 * calling unbind (which may remove the active reference 222 * of any of our objects, thus corrupting the list). 223 */ 224 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 225 if (drm_mm_scan_remove_block(&scan, &vma->node)) 226 __i915_vma_pin(vma); 227 else 228 list_del(&vma->evict_link); 229 } 230 231 /* Unbinding will emit any required flushes */ 232 ret = 0; 233 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 234 __i915_vma_unpin(vma); 235 if (ret == 0) 236 ret = __i915_vma_unbind(vma); 237 } 238 239 while (ret == 0 && (node = drm_mm_scan_color_evict(&scan))) { 240 vma = container_of(node, struct i915_vma, node); 241 242 /* If we find any non-objects (!vma), we cannot evict them */ 243 if (vma->node.color != I915_COLOR_UNEVICTABLE) 244 ret = __i915_vma_unbind(vma); 245 else 246 ret = -ENOSPC; /* XXX search failed, try again? */ 247 } 248 249 return ret; 250 } 251 252 /** 253 * i915_gem_evict_for_node - 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 int ret = 0; 273 274 lockdep_assert_held(&vm->mutex); 275 GEM_BUG_ON(!IS_ALIGNED(start, I915_GTT_PAGE_SIZE)); 276 GEM_BUG_ON(!IS_ALIGNED(end, I915_GTT_PAGE_SIZE)); 277 278 trace_i915_gem_evict_node(vm, target, flags); 279 280 /* 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 intel_gt_retire_requests(vm->gt); 287 288 if (i915_vm_has_cache_coloring(vm)) { 289 /* Expand search to cover neighbouring guard pages (or lack!) */ 290 if (start) 291 start -= I915_GTT_PAGE_SIZE; 292 293 /* Always look at the page afterwards to avoid the end-of-GTT */ 294 end += I915_GTT_PAGE_SIZE; 295 } 296 GEM_BUG_ON(start >= end); 297 298 drm_mm_for_each_node_in_range(node, &vm->mm, start, end) { 299 /* If we find any non-objects (!vma), we cannot evict them */ 300 if (node->color == I915_COLOR_UNEVICTABLE) { 301 ret = -ENOSPC; 302 break; 303 } 304 305 GEM_BUG_ON(!drm_mm_node_allocated(node)); 306 vma = container_of(node, typeof(*vma), node); 307 308 /* 309 * If we are using coloring to insert guard pages between 310 * different cache domains within the address space, we have 311 * to check whether the objects on either side of our range 312 * abutt and conflict. If they are in conflict, then we evict 313 * those as well to make room for our guard pages. 314 */ 315 if (i915_vm_has_cache_coloring(vm)) { 316 if (node->start + node->size == target->start) { 317 if (node->color == target->color) 318 continue; 319 } 320 if (node->start == target->start + target->size) { 321 if (node->color == target->color) 322 continue; 323 } 324 } 325 326 if (i915_vma_is_pinned(vma)) { 327 ret = -ENOSPC; 328 break; 329 } 330 331 if (flags & PIN_NONBLOCK && i915_vma_is_active(vma)) { 332 ret = -ENOSPC; 333 break; 334 } 335 336 /* 337 * Never show fear in the face of dragons! 338 * 339 * We cannot directly remove this node from within this 340 * iterator and as with i915_gem_evict_something() we employ 341 * the vma pin_count in order to prevent the action of 342 * unbinding one vma from freeing (by dropping its active 343 * reference) another in our eviction list. 344 */ 345 __i915_vma_pin(vma); 346 list_add(&vma->evict_link, &eviction_list); 347 } 348 349 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) { 350 __i915_vma_unpin(vma); 351 if (ret == 0) 352 ret = __i915_vma_unbind(vma); 353 } 354 355 return ret; 356 } 357 358 /** 359 * i915_gem_evict_vm - Evict all idle vmas from a vm 360 * @vm: Address space to cleanse 361 * 362 * This function evicts all vmas from a vm. 363 * 364 * This is used by the execbuf code as a last-ditch effort to defragment the 365 * address space. 366 * 367 * To clarify: This is for freeing up virtual address space, not for freeing 368 * memory in e.g. the shrinker. 369 */ 370 int i915_gem_evict_vm(struct i915_address_space *vm) 371 { 372 int ret = 0; 373 374 lockdep_assert_held(&vm->mutex); 375 trace_i915_gem_evict_vm(vm); 376 377 /* Switch back to the default context in order to unpin 378 * the existing context objects. However, such objects only 379 * pin themselves inside the global GTT and performing the 380 * switch otherwise is ineffective. 381 */ 382 if (i915_is_ggtt(vm)) { 383 ret = ggtt_flush(vm->gt); 384 if (ret) 385 return ret; 386 } 387 388 do { 389 struct i915_vma *vma, *vn; 390 LIST_HEAD(eviction_list); 391 392 list_for_each_entry(vma, &vm->bound_list, vm_link) { 393 if (i915_vma_is_pinned(vma)) 394 continue; 395 396 __i915_vma_pin(vma); 397 list_add(&vma->evict_link, &eviction_list); 398 } 399 if (list_empty(&eviction_list)) 400 break; 401 402 ret = 0; 403 list_for_each_entry_safe(vma, vn, &eviction_list, evict_link) { 404 __i915_vma_unpin(vma); 405 if (ret == 0) 406 ret = __i915_vma_unbind(vma); 407 if (ret != -EINTR) /* "Get me out of here!" */ 408 ret = 0; 409 } 410 } while (ret == 0); 411 412 return ret; 413 } 414 415 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST) 416 #include "selftests/i915_gem_evict.c" 417 #endif 418