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
I915_SELFTEST_DECLARE(static struct igt_evict_ctl{ bool fail_if_busy:1; } igt_evict_ctl;)36 I915_SELFTEST_DECLARE(static struct igt_evict_ctl {
37 bool fail_if_busy:1;
38 } igt_evict_ctl;)
39
40 static bool ggtt_is_idle(struct drm_i915_private *i915)
41 {
42 struct intel_engine_cs *engine;
43 enum intel_engine_id id;
44
45 if (i915->gt.active_requests)
46 return false;
47
48 for_each_engine(engine, i915, id) {
49 if (engine->last_retired_context != i915->kernel_context)
50 return false;
51 }
52
53 return true;
54 }
55
ggtt_flush(struct drm_i915_private * i915)56 static int ggtt_flush(struct drm_i915_private *i915)
57 {
58 int err;
59
60 /* Not everything in the GGTT is tracked via vma (otherwise we
61 * could evict as required with minimal stalling) so we are forced
62 * to idle the GPU and explicitly retire outstanding requests in
63 * the hopes that we can then remove contexts and the like only
64 * bound by their active reference.
65 */
66 err = i915_gem_switch_to_kernel_context(i915);
67 if (err)
68 return err;
69
70 err = i915_gem_wait_for_idle(i915,
71 I915_WAIT_INTERRUPTIBLE |
72 I915_WAIT_LOCKED);
73 if (err)
74 return err;
75
76 return 0;
77 }
78
79 static bool
mark_free(struct drm_mm_scan * scan,struct i915_vma * vma,unsigned int flags,struct list_head * unwind)80 mark_free(struct drm_mm_scan *scan,
81 struct i915_vma *vma,
82 unsigned int flags,
83 struct list_head *unwind)
84 {
85 if (i915_vma_is_pinned(vma))
86 return false;
87
88 if (flags & PIN_NONFAULT && i915_vma_has_userfault(vma))
89 return false;
90
91 list_add(&vma->evict_link, unwind);
92 return drm_mm_scan_add_block(scan, &vma->node);
93 }
94
95 /**
96 * i915_gem_evict_something - Evict vmas to make room for binding a new one
97 * @vm: address space to evict from
98 * @min_size: size of the desired free space
99 * @alignment: alignment constraint of the desired free space
100 * @cache_level: cache_level for the desired space
101 * @start: start (inclusive) of the range from which to evict objects
102 * @end: end (exclusive) of the range from which to evict objects
103 * @flags: additional flags to control the eviction algorithm
104 *
105 * This function will try to evict vmas until a free space satisfying the
106 * requirements is found. Callers must check first whether any such hole exists
107 * already before calling this function.
108 *
109 * This function is used by the object/vma binding code.
110 *
111 * Since this function is only used to free up virtual address space it only
112 * ignores pinned vmas, and not object where the backing storage itself is
113 * pinned. Hence obj->pages_pin_count does not protect against eviction.
114 *
115 * To clarify: This is for freeing up virtual address space, not for freeing
116 * memory in e.g. the shrinker.
117 */
118 int
i915_gem_evict_something(struct i915_address_space * vm,u64 min_size,u64 alignment,unsigned cache_level,u64 start,u64 end,unsigned flags)119 i915_gem_evict_something(struct i915_address_space *vm,
120 u64 min_size, u64 alignment,
121 unsigned cache_level,
122 u64 start, u64 end,
123 unsigned flags)
124 {
125 struct drm_i915_private *dev_priv = vm->i915;
126 struct drm_mm_scan scan;
127 struct list_head eviction_list;
128 struct list_head *phases[] = {
129 &vm->inactive_list,
130 &vm->active_list,
131 NULL,
132 }, **phase;
133 struct i915_vma *vma, *next;
134 struct drm_mm_node *node;
135 enum drm_mm_insert_mode mode;
136 int ret;
137
138 lockdep_assert_held(&vm->i915->drm.struct_mutex);
139 trace_i915_gem_evict(vm, min_size, alignment, flags);
140
141 /*
142 * The goal is to evict objects and amalgamate space in LRU order.
143 * The oldest idle objects reside on the inactive list, which is in
144 * retirement order. The next objects to retire are those in flight,
145 * on the active list, again in retirement order.
146 *
147 * The retirement sequence is thus:
148 * 1. Inactive objects (already retired)
149 * 2. Active objects (will stall on unbinding)
150 *
151 * On each list, the oldest objects lie at the HEAD with the freshest
152 * object on the TAIL.
153 */
154 kprintf("i915_gem_evict_something: %016llx-%016llx\n", start, end);
155 mode = DRM_MM_INSERT_BEST;
156 if (flags & PIN_HIGH)
157 mode = DRM_MM_INSERT_HIGH;
158 if (flags & PIN_MAPPABLE)
159 mode = DRM_MM_INSERT_LOW;
160 drm_mm_scan_init_with_range(&scan, &vm->mm,
161 min_size, alignment, cache_level,
162 start, end, mode);
163
164 /*
165 * Retire before we search the active list. Although we have
166 * reasonable accuracy in our retirement lists, we may have
167 * a stray pin (preventing eviction) that can only be resolved by
168 * retiring.
169 */
170 if (!(flags & PIN_NONBLOCK))
171 i915_gem_retire_requests(dev_priv);
172 else
173 phases[1] = NULL;
174
175 search_again:
176 INIT_LIST_HEAD(&eviction_list);
177 phase = phases;
178 do {
179 list_for_each_entry(vma, *phase, vm_link)
180 if (mark_free(&scan, vma, flags, &eviction_list))
181 goto found;
182 } while (*++phase);
183
184 /* Nothing found, clean up and bail out! */
185 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
186 ret = drm_mm_scan_remove_block(&scan, &vma->node);
187 BUG_ON(ret);
188 }
189
190 /*
191 * Can we unpin some objects such as idle hw contents,
192 * or pending flips? But since only the GGTT has global entries
193 * such as scanouts, rinbuffers and contexts, we can skip the
194 * purge when inspecting per-process local address spaces.
195 */
196 if (!i915_is_ggtt(vm) || flags & PIN_NONBLOCK) {
197 return -ENOSPC;
198 }
199 kprintf("i915_gem_evict_something: Nothing found %d,%d\n",
200 ggtt_is_idle(dev_priv),
201 intel_has_pending_fb_unpin(dev_priv));
202
203 /*
204 * Not everything in the GGTT is tracked via VMA using
205 * i915_vma_move_to_active(), otherwise we could evict as required
206 * with minimal stalling. Instead we are forced to idle the GPU and
207 * explicitly retire outstanding requests which will then remove
208 * the pinning for active objects such as contexts and ring,
209 * enabling us to evict them on the next iteration.
210 *
211 * To ensure that all user contexts are evictable, we perform
212 * a switch to the perma-pinned kernel context. This all also gives
213 * us a termination condition, when the last retired context is
214 * the kernel's there is no more we can evict.
215 */
216 if (!ggtt_is_idle(dev_priv)) {
217 if (I915_SELFTEST_ONLY(igt_evict_ctl.fail_if_busy))
218 return -EBUSY;
219
220 ret = ggtt_flush(dev_priv);
221 if (ret)
222 return ret;
223
224 goto search_again;
225 }
226
227 /*
228 * If we still have pending pageflip completions, drop
229 * back to userspace to give our workqueues time to
230 * acquire our locks and unpin the old scanouts.
231 */
232 return intel_has_pending_fb_unpin(dev_priv) ? -EAGAIN : -ENOSPC;
233
234 found:
235 /* drm_mm doesn't allow any other other operations while
236 * scanning, therefore store to-be-evicted objects on a
237 * temporary list and take a reference for all before
238 * calling unbind (which may remove the active reference
239 * of any of our objects, thus corrupting the list).
240 */
241 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
242 if (drm_mm_scan_remove_block(&scan, &vma->node))
243 __i915_vma_pin(vma);
244 else
245 list_del(&vma->evict_link);
246 }
247
248 /* Unbinding will emit any required flushes */
249 ret = 0;
250 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
251 __i915_vma_unpin(vma);
252 if (ret == 0)
253 ret = i915_vma_unbind(vma);
254 }
255
256 while (ret == 0 && (node = drm_mm_scan_color_evict(&scan))) {
257 vma = container_of(node, struct i915_vma, node);
258 ret = i915_vma_unbind(vma);
259 }
260
261 return ret;
262 }
263
264 /**
265 * i915_gem_evict_for_vma - Evict vmas to make room for binding a new one
266 * @vm: address space to evict from
267 * @target: range (and color) to evict for
268 * @flags: additional flags to control the eviction algorithm
269 *
270 * This function will try to evict vmas that overlap the target node.
271 *
272 * To clarify: This is for freeing up virtual address space, not for freeing
273 * memory in e.g. the shrinker.
274 */
i915_gem_evict_for_node(struct i915_address_space * vm,struct drm_mm_node * target,unsigned int flags)275 int i915_gem_evict_for_node(struct i915_address_space *vm,
276 struct drm_mm_node *target,
277 unsigned int flags)
278 {
279 LINUX_LIST_HEAD(eviction_list);
280 struct drm_mm_node *node;
281 u64 start = target->start;
282 u64 end = start + target->size;
283 struct i915_vma *vma, *next;
284 bool check_color;
285 int ret = 0;
286
287 lockdep_assert_held(&vm->i915->drm.struct_mutex);
288 GEM_BUG_ON(!IS_ALIGNED(start, I915_GTT_PAGE_SIZE));
289 GEM_BUG_ON(!IS_ALIGNED(end, I915_GTT_PAGE_SIZE));
290
291 trace_i915_gem_evict_node(vm, target, flags);
292
293 /* Retire before we search the active list. Although we have
294 * reasonable accuracy in our retirement lists, we may have
295 * a stray pin (preventing eviction) that can only be resolved by
296 * retiring.
297 */
298 if (!(flags & PIN_NONBLOCK))
299 i915_gem_retire_requests(vm->i915);
300
301 check_color = vm->mm.color_adjust;
302 if (check_color) {
303 /* Expand search to cover neighbouring guard pages (or lack!) */
304 if (start)
305 start -= I915_GTT_PAGE_SIZE;
306
307 /* Always look at the page afterwards to avoid the end-of-GTT */
308 end += I915_GTT_PAGE_SIZE;
309 }
310 GEM_BUG_ON(start >= end);
311
312 drm_mm_for_each_node_in_range(node, &vm->mm, start, end) {
313 /* If we find any non-objects (!vma), we cannot evict them */
314 if (node->color == I915_COLOR_UNEVICTABLE) {
315 ret = -ENOSPC;
316 break;
317 }
318
319 GEM_BUG_ON(!node->allocated);
320 vma = container_of(node, typeof(*vma), node);
321
322 /* If we are using coloring to insert guard pages between
323 * different cache domains within the address space, we have
324 * to check whether the objects on either side of our range
325 * abutt and conflict. If they are in conflict, then we evict
326 * those as well to make room for our guard pages.
327 */
328 if (check_color) {
329 if (node->start + node->size == target->start) {
330 if (node->color == target->color)
331 continue;
332 }
333 if (node->start == target->start + target->size) {
334 if (node->color == target->color)
335 continue;
336 }
337 }
338
339 if (flags & PIN_NONBLOCK &&
340 (i915_vma_is_pinned(vma) || i915_vma_is_active(vma))) {
341 ret = -ENOSPC;
342 break;
343 }
344
345 if (flags & PIN_NONFAULT && i915_vma_has_userfault(vma)) {
346 ret = -ENOSPC;
347 break;
348 }
349
350 /* Overlap of objects in the same batch? */
351 if (i915_vma_is_pinned(vma)) {
352 ret = -ENOSPC;
353 if (vma->exec_flags &&
354 *vma->exec_flags & EXEC_OBJECT_PINNED)
355 ret = -EINVAL;
356 break;
357 }
358
359 /* Never show fear in the face of dragons!
360 *
361 * We cannot directly remove this node from within this
362 * iterator and as with i915_gem_evict_something() we employ
363 * the vma pin_count in order to prevent the action of
364 * unbinding one vma from freeing (by dropping its active
365 * reference) another in our eviction list.
366 */
367 __i915_vma_pin(vma);
368 list_add(&vma->evict_link, &eviction_list);
369 }
370
371 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
372 __i915_vma_unpin(vma);
373 if (ret == 0)
374 ret = i915_vma_unbind(vma);
375 }
376
377 return ret;
378 }
379
380 /**
381 * i915_gem_evict_vm - Evict all idle vmas from a vm
382 * @vm: Address space to cleanse
383 *
384 * This function evicts all vmas from a vm.
385 *
386 * This is used by the execbuf code as a last-ditch effort to defragment the
387 * address space.
388 *
389 * To clarify: This is for freeing up virtual address space, not for freeing
390 * memory in e.g. the shrinker.
391 */
i915_gem_evict_vm(struct i915_address_space * vm)392 int i915_gem_evict_vm(struct i915_address_space *vm)
393 {
394 struct list_head *phases[] = {
395 &vm->inactive_list,
396 &vm->active_list,
397 NULL
398 }, **phase;
399 struct list_head eviction_list;
400 struct i915_vma *vma, *next;
401 int ret;
402
403 lockdep_assert_held(&vm->i915->drm.struct_mutex);
404 trace_i915_gem_evict_vm(vm);
405
406 /* Switch back to the default context in order to unpin
407 * the existing context objects. However, such objects only
408 * pin themselves inside the global GTT and performing the
409 * switch otherwise is ineffective.
410 */
411 if (i915_is_ggtt(vm)) {
412 ret = ggtt_flush(vm->i915);
413 if (ret)
414 return ret;
415 }
416
417 INIT_LIST_HEAD(&eviction_list);
418 phase = phases;
419 do {
420 list_for_each_entry(vma, *phase, vm_link) {
421 if (i915_vma_is_pinned(vma))
422 continue;
423
424 __i915_vma_pin(vma);
425 list_add(&vma->evict_link, &eviction_list);
426 }
427 } while (*++phase);
428
429 ret = 0;
430 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
431 __i915_vma_unpin(vma);
432 if (ret == 0)
433 ret = i915_vma_unbind(vma);
434 }
435 return ret;
436 }
437
438 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
439 #include "selftests/i915_gem_evict.c"
440 #endif
441