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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
36static bool
37mark_free(struct i915_vma *vma, struct list_head *unwind)
38{
39 if (vma->pin_count)
40 return false;
41
42 if (WARN_ON(!list_empty(&vma->exec_list)))
43 return false;
44
45 list_add(&vma->exec_list, unwind);
46 return drm_mm_scan_add_block(&vma->node);
47}
48
49/**
50 * i915_gem_evict_something - Evict vmas to make room for binding a new one
51 * @dev: drm_device
52 * @vm: address space to evict from
53 * @min_size: size of the desired free space
54 * @alignment: alignment constraint of the desired free space
55 * @cache_level: cache_level for the desired space
56 * @start: start (inclusive) of the range from which to evict objects
57 * @end: end (exclusive) of the range from which to evict objects
58 * @flags: additional flags to control the eviction algorithm
59 *
60 * This function will try to evict vmas until a free space satisfying the
61 * requirements is found. Callers must check first whether any such hole exists
62 * already before calling this function.
63 *
64 * This function is used by the object/vma binding code.
65 *
66 * Since this function is only used to free up virtual address space it only
67 * ignores pinned vmas, and not object where the backing storage itself is
68 * pinned. Hence obj->pages_pin_count does not protect against eviction.
69 *
70 * To clarify: This is for freeing up virtual address space, not for freeing
71 * memory in e.g. the shrinker.
72 */
73int
74i915_gem_evict_something(struct drm_device *dev, struct i915_address_space *vm,
75 int min_size, unsigned alignment, unsigned cache_level,
76 unsigned long start, unsigned long end,
77 unsigned flags)
78{
79 struct list_head eviction_list, unwind_list;
80 struct i915_vma *vma;
81 int ret = 0;
82 int pass = 0;
83
84 trace_i915_gem_evict(dev, min_size, alignment, flags);
85
86 /*
87 * The goal is to evict objects and amalgamate space in LRU order.
88 * The oldest idle objects reside on the inactive list, which is in
89 * retirement order. The next objects to retire are those on the (per
90 * ring) active list that do not have an outstanding flush. Once the
91 * hardware reports completion (the seqno is updated after the
92 * batchbuffer has been finished) the clean buffer objects would
93 * be retired to the inactive list. Any dirty objects would be added
94 * to the tail of the flushing list. So after processing the clean
95 * active objects we need to emit a MI_FLUSH to retire the flushing
96 * list, hence the retirement order of the flushing list is in
97 * advance of the dirty objects on the active lists.
98 *
99 * The retirement sequence is thus:
100 * 1. Inactive objects (already retired)
101 * 2. Clean active objects
102 * 3. Flushing list
103 * 4. Dirty active objects.
104 *
105 * On each list, the oldest objects lie at the HEAD with the freshest
106 * object on the TAIL.
107 */
108
109 INIT_LIST_HEAD(&unwind_list);
110 if (start != 0 || end != vm->total) {
111 drm_mm_init_scan_with_range(&vm->mm, min_size,
112 alignment, cache_level,
113 start, end);
114 } else
115 drm_mm_init_scan(&vm->mm, min_size, alignment, cache_level);
116
117search_again:
118 /* First see if there is a large enough contiguous idle region... */
119 list_for_each_entry(vma, &vm->inactive_list, vm_link) {
120 if (mark_free(vma, &unwind_list))
121 goto found;
122 }
123
124 if (flags & PIN_NONBLOCK)
125 goto none;
126
127 /* Now merge in the soon-to-be-expired objects... */
128 list_for_each_entry(vma, &vm->active_list, vm_link) {
129 if (mark_free(vma, &unwind_list))
130 goto found;
131 }
132
133none:
134 /* Nothing found, clean up and bail out! */
135 while (!list_empty(&unwind_list)) {
136 vma = list_first_entry(&unwind_list,
137 struct i915_vma,
138 exec_list);
139 ret = drm_mm_scan_remove_block(&vma->node);
140 BUG_ON(ret);
141
142 list_del_init(&vma->exec_list);
143 }
144
145 /* Can we unpin some objects such as idle hw contents,
146 * or pending flips?
147 */
148 if (flags & PIN_NONBLOCK)
149 return -ENOSPC;
150
151 /* Only idle the GPU and repeat the search once */
152 if (pass++ == 0) {
153 ret = i915_gpu_idle(dev);
154 if (ret)
155 return ret;
156
157 i915_gem_retire_requests(dev);
158 goto search_again;
159 }
160
161 /* If we still have pending pageflip completions, drop
162 * back to userspace to give our workqueues time to
163 * acquire our locks and unpin the old scanouts.
164 */
165 return intel_has_pending_fb_unpin(dev) ? -EAGAIN : -ENOSPC;
166
167found:
168 /* drm_mm doesn't allow any other other operations while
169 * scanning, therefore store to be evicted objects on a
170 * temporary list. */
171 INIT_LIST_HEAD(&eviction_list);
172 while (!list_empty(&unwind_list)) {
173 vma = list_first_entry(&unwind_list,
174 struct i915_vma,
175 exec_list);
176 if (drm_mm_scan_remove_block(&vma->node)) {
177 list_move(&vma->exec_list, &eviction_list);
178 drm_gem_object_reference(&vma->obj->base);
179 continue;
180 }
181 list_del_init(&vma->exec_list);
182 }
183
184 /* Unbinding will emit any required flushes */
185 while (!list_empty(&eviction_list)) {
186 struct drm_gem_object *obj;
187 vma = list_first_entry(&eviction_list,
188 struct i915_vma,
189 exec_list);
190
191 obj = &vma->obj->base;
192 list_del_init(&vma->exec_list);
193 if (ret == 0)
194 ret = i915_vma_unbind(vma);
195
196 drm_gem_object_unreference(obj);
197 }
198
199 return ret;
200}
201
202int
203i915_gem_evict_for_vma(struct i915_vma *target)
204{
205 struct drm_mm_node *node, *next;
206
207 list_for_each_entry_safe(node, next,
208 &target->vm->mm.head_node.node_list,
209 node_list) {
210 struct i915_vma *vma;
211 int ret;
212
213 if (node->start + node->size <= target->node.start)
214 continue;
215 if (node->start >= target->node.start + target->node.size)
216 break;
217
218 vma = container_of(node, typeof(*vma), node);
219
220 if (vma->pin_count) {
221 if (!vma->exec_entry || (vma->pin_count > 1))
222 /* Object is pinned for some other use */
223 return -EBUSY;
224
225 /* We need to evict a buffer in the same batch */
226 if (vma->exec_entry->flags & EXEC_OBJECT_PINNED)
227 /* Overlapping fixed objects in the same batch */
228 return -EINVAL;
229
230 return -ENOSPC;
231 }
232
233 ret = i915_vma_unbind(vma);
234 if (ret)
235 return ret;
236 }
237
238 return 0;
239}
240
241/**
242 * i915_gem_evict_vm - Evict all idle vmas from a vm
243 * @vm: Address space to cleanse
244 * @do_idle: Boolean directing whether to idle first.
245 *
246 * This function evicts all idles vmas from a vm. If all unpinned vmas should be
247 * evicted the @do_idle needs to be set to true.
248 *
249 * This is used by the execbuf code as a last-ditch effort to defragment the
250 * address space.
251 *
252 * To clarify: This is for freeing up virtual address space, not for freeing
253 * memory in e.g. the shrinker.
254 */
255int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)
256{
257 struct i915_vma *vma, *next;
258 int ret;
259
260 WARN_ON(!mutex_is_locked(&vm->dev->struct_mutex));
261 trace_i915_gem_evict_vm(vm);
262
263 if (do_idle) {
264 ret = i915_gpu_idle(vm->dev);
265 if (ret)
266 return ret;
267
268 i915_gem_retire_requests(vm->dev);
269
270 WARN_ON(!list_empty(&vm->active_list));
271 }
272
273 list_for_each_entry_safe(vma, next, &vm->inactive_list, vm_link)
274 if (vma->pin_count == 0)
275 WARN_ON(i915_vma_unbind(vma));
276
277 return 0;
278}
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_gem_evict.h"
35#include "i915_trace.h"
36
37I915_SELFTEST_DECLARE(static struct igt_evict_ctl {
38 bool fail_if_busy:1;
39} igt_evict_ctl;)
40
41static bool dying_vma(struct i915_vma *vma)
42{
43 return !kref_read(&vma->obj->base.refcount);
44}
45
46static int ggtt_flush(struct intel_gt *gt)
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 return intel_gt_wait_for_idle(gt, MAX_SCHEDULE_TIMEOUT);
56}
57
58static bool grab_vma(struct i915_vma *vma, struct i915_gem_ww_ctx *ww)
59{
60 /*
61 * We add the extra refcount so the object doesn't drop to zero until
62 * after ungrab_vma(), this way trylock is always paired with unlock.
63 */
64 if (i915_gem_object_get_rcu(vma->obj)) {
65 if (!i915_gem_object_trylock(vma->obj, ww)) {
66 i915_gem_object_put(vma->obj);
67 return false;
68 }
69 } else {
70 /* Dead objects don't need pins */
71 atomic_and(~I915_VMA_PIN_MASK, &vma->flags);
72 }
73
74 return true;
75}
76
77static void ungrab_vma(struct i915_vma *vma)
78{
79 if (dying_vma(vma))
80 return;
81
82 i915_gem_object_unlock(vma->obj);
83 i915_gem_object_put(vma->obj);
84}
85
86static bool
87mark_free(struct drm_mm_scan *scan,
88 struct i915_gem_ww_ctx *ww,
89 struct i915_vma *vma,
90 unsigned int flags,
91 struct list_head *unwind)
92{
93 if (i915_vma_is_pinned(vma))
94 return false;
95
96 if (!grab_vma(vma, ww))
97 return false;
98
99 list_add(&vma->evict_link, unwind);
100 return drm_mm_scan_add_block(scan, &vma->node);
101}
102
103static bool defer_evict(struct i915_vma *vma)
104{
105 if (i915_vma_is_active(vma))
106 return true;
107
108 if (i915_vma_is_scanout(vma))
109 return true;
110
111 return false;
112}
113
114/**
115 * i915_gem_evict_something - Evict vmas to make room for binding a new one
116 * @vm: address space to evict from
117 * @ww: An optional struct i915_gem_ww_ctx.
118 * @min_size: size of the desired free space
119 * @alignment: alignment constraint of the desired free space
120 * @color: color for the desired space
121 * @start: start (inclusive) of the range from which to evict objects
122 * @end: end (exclusive) of the range from which to evict objects
123 * @flags: additional flags to control the eviction algorithm
124 *
125 * This function will try to evict vmas until a free space satisfying the
126 * requirements is found. Callers must check first whether any such hole exists
127 * already before calling this function.
128 *
129 * This function is used by the object/vma binding code.
130 *
131 * Since this function is only used to free up virtual address space it only
132 * ignores pinned vmas, and not object where the backing storage itself is
133 * pinned. Hence obj->pages_pin_count does not protect against eviction.
134 *
135 * To clarify: This is for freeing up virtual address space, not for freeing
136 * memory in e.g. the shrinker.
137 */
138int
139i915_gem_evict_something(struct i915_address_space *vm,
140 struct i915_gem_ww_ctx *ww,
141 u64 min_size, u64 alignment,
142 unsigned long color,
143 u64 start, u64 end,
144 unsigned flags)
145{
146 struct drm_mm_scan scan;
147 struct list_head eviction_list;
148 struct i915_vma *vma, *next;
149 struct drm_mm_node *node;
150 enum drm_mm_insert_mode mode;
151 struct i915_vma *active;
152 int ret;
153
154 lockdep_assert_held(&vm->mutex);
155 trace_i915_gem_evict(vm, min_size, alignment, flags);
156
157 /*
158 * The goal is to evict objects and amalgamate space in rough LRU order.
159 * Since both active and inactive objects reside on the same list,
160 * in a mix of creation and last scanned order, as we process the list
161 * we sort it into inactive/active, which keeps the active portion
162 * in a rough MRU order.
163 *
164 * The retirement sequence is thus:
165 * 1. Inactive objects (already retired, random order)
166 * 2. Active objects (will stall on unbinding, oldest scanned first)
167 */
168 mode = DRM_MM_INSERT_BEST;
169 if (flags & PIN_HIGH)
170 mode = DRM_MM_INSERT_HIGH;
171 if (flags & PIN_MAPPABLE)
172 mode = DRM_MM_INSERT_LOW;
173 drm_mm_scan_init_with_range(&scan, &vm->mm,
174 min_size, alignment, color,
175 start, end, mode);
176
177 intel_gt_retire_requests(vm->gt);
178
179search_again:
180 active = NULL;
181 INIT_LIST_HEAD(&eviction_list);
182 list_for_each_entry_safe(vma, next, &vm->bound_list, vm_link) {
183 if (vma == active) { /* now seen this vma twice */
184 if (flags & PIN_NONBLOCK)
185 break;
186
187 active = ERR_PTR(-EAGAIN);
188 }
189
190 /*
191 * We keep this list in a rough least-recently scanned order
192 * of active elements (inactive elements are cheap to reap).
193 * New entries are added to the end, and we move anything we
194 * scan to the end. The assumption is that the working set
195 * of applications is either steady state (and thanks to the
196 * userspace bo cache it almost always is) or volatile and
197 * frequently replaced after a frame, which are self-evicting!
198 * Given that assumption, the MRU order of the scan list is
199 * fairly static, and keeping it in least-recently scan order
200 * is suitable.
201 *
202 * To notice when we complete one full cycle, we record the
203 * first active element seen, before moving it to the tail.
204 */
205 if (active != ERR_PTR(-EAGAIN) && defer_evict(vma)) {
206 if (!active)
207 active = vma;
208
209 list_move_tail(&vma->vm_link, &vm->bound_list);
210 continue;
211 }
212
213 if (mark_free(&scan, ww, vma, flags, &eviction_list))
214 goto found;
215 }
216
217 /* Nothing found, clean up and bail out! */
218 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
219 ret = drm_mm_scan_remove_block(&scan, &vma->node);
220 BUG_ON(ret);
221 ungrab_vma(vma);
222 }
223
224 /*
225 * Can we unpin some objects such as idle hw contents,
226 * or pending flips? But since only the GGTT has global entries
227 * such as scanouts, rinbuffers and contexts, we can skip the
228 * purge when inspecting per-process local address spaces.
229 */
230 if (!i915_is_ggtt(vm) || flags & PIN_NONBLOCK)
231 return -ENOSPC;
232
233 /*
234 * Not everything in the GGTT is tracked via VMA using
235 * i915_vma_move_to_active(), otherwise we could evict as required
236 * with minimal stalling. Instead we are forced to idle the GPU and
237 * explicitly retire outstanding requests which will then remove
238 * the pinning for active objects such as contexts and ring,
239 * enabling us to evict them on the next iteration.
240 *
241 * To ensure that all user contexts are evictable, we perform
242 * a switch to the perma-pinned kernel context. This all also gives
243 * us a termination condition, when the last retired context is
244 * the kernel's there is no more we can evict.
245 */
246 if (I915_SELFTEST_ONLY(igt_evict_ctl.fail_if_busy))
247 return -EBUSY;
248
249 ret = ggtt_flush(vm->gt);
250 if (ret)
251 return ret;
252
253 cond_resched();
254
255 flags |= PIN_NONBLOCK;
256 goto search_again;
257
258found:
259 /* drm_mm doesn't allow any other other operations while
260 * scanning, therefore store to-be-evicted objects on a
261 * temporary list and take a reference for all before
262 * calling unbind (which may remove the active reference
263 * of any of our objects, thus corrupting the list).
264 */
265 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
266 if (drm_mm_scan_remove_block(&scan, &vma->node)) {
267 __i915_vma_pin(vma);
268 } else {
269 list_del(&vma->evict_link);
270 ungrab_vma(vma);
271 }
272 }
273
274 /* Unbinding will emit any required flushes */
275 ret = 0;
276 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
277 __i915_vma_unpin(vma);
278 if (ret == 0)
279 ret = __i915_vma_unbind(vma);
280 ungrab_vma(vma);
281 }
282
283 while (ret == 0 && (node = drm_mm_scan_color_evict(&scan))) {
284 vma = container_of(node, struct i915_vma, node);
285
286 /* If we find any non-objects (!vma), we cannot evict them */
287 if (vma->node.color != I915_COLOR_UNEVICTABLE &&
288 grab_vma(vma, ww)) {
289 ret = __i915_vma_unbind(vma);
290 ungrab_vma(vma);
291 } else {
292 ret = -ENOSPC;
293 }
294 }
295
296 return ret;
297}
298
299/**
300 * i915_gem_evict_for_node - Evict vmas to make room for binding a new one
301 * @vm: address space to evict from
302 * @ww: An optional struct i915_gem_ww_ctx.
303 * @target: range (and color) to evict for
304 * @flags: additional flags to control the eviction algorithm
305 *
306 * This function will try to evict vmas that overlap the target node.
307 *
308 * To clarify: This is for freeing up virtual address space, not for freeing
309 * memory in e.g. the shrinker.
310 */
311int i915_gem_evict_for_node(struct i915_address_space *vm,
312 struct i915_gem_ww_ctx *ww,
313 struct drm_mm_node *target,
314 unsigned int flags)
315{
316 LIST_HEAD(eviction_list);
317 struct drm_mm_node *node;
318 u64 start = target->start;
319 u64 end = start + target->size;
320 struct i915_vma *vma, *next;
321 int ret = 0;
322
323 lockdep_assert_held(&vm->mutex);
324 GEM_BUG_ON(!IS_ALIGNED(start, I915_GTT_PAGE_SIZE));
325 GEM_BUG_ON(!IS_ALIGNED(end, I915_GTT_PAGE_SIZE));
326
327 trace_i915_gem_evict_node(vm, target, flags);
328
329 /*
330 * Retire before we search the active list. Although we have
331 * reasonable accuracy in our retirement lists, we may have
332 * a stray pin (preventing eviction) that can only be resolved by
333 * retiring.
334 */
335 intel_gt_retire_requests(vm->gt);
336
337 if (i915_vm_has_cache_coloring(vm)) {
338 /* Expand search to cover neighbouring guard pages (or lack!) */
339 if (start)
340 start -= I915_GTT_PAGE_SIZE;
341
342 /* Always look at the page afterwards to avoid the end-of-GTT */
343 end += I915_GTT_PAGE_SIZE;
344 }
345 GEM_BUG_ON(start >= end);
346
347 drm_mm_for_each_node_in_range(node, &vm->mm, start, end) {
348 /* If we find any non-objects (!vma), we cannot evict them */
349 if (node->color == I915_COLOR_UNEVICTABLE) {
350 ret = -ENOSPC;
351 break;
352 }
353
354 GEM_BUG_ON(!drm_mm_node_allocated(node));
355 vma = container_of(node, typeof(*vma), node);
356
357 /*
358 * If we are using coloring to insert guard pages between
359 * different cache domains within the address space, we have
360 * to check whether the objects on either side of our range
361 * abutt and conflict. If they are in conflict, then we evict
362 * those as well to make room for our guard pages.
363 */
364 if (i915_vm_has_cache_coloring(vm)) {
365 if (node->start + node->size == target->start) {
366 if (node->color == target->color)
367 continue;
368 }
369 if (node->start == target->start + target->size) {
370 if (node->color == target->color)
371 continue;
372 }
373 }
374
375 if (i915_vma_is_pinned(vma)) {
376 ret = -ENOSPC;
377 break;
378 }
379
380 if (flags & PIN_NONBLOCK && i915_vma_is_active(vma)) {
381 ret = -ENOSPC;
382 break;
383 }
384
385 if (!grab_vma(vma, ww)) {
386 ret = -ENOSPC;
387 break;
388 }
389
390 /*
391 * Never show fear in the face of dragons!
392 *
393 * We cannot directly remove this node from within this
394 * iterator and as with i915_gem_evict_something() we employ
395 * the vma pin_count in order to prevent the action of
396 * unbinding one vma from freeing (by dropping its active
397 * reference) another in our eviction list.
398 */
399 __i915_vma_pin(vma);
400 list_add(&vma->evict_link, &eviction_list);
401 }
402
403 list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
404 __i915_vma_unpin(vma);
405 if (ret == 0)
406 ret = __i915_vma_unbind(vma);
407
408 ungrab_vma(vma);
409 }
410
411 return ret;
412}
413
414/**
415 * i915_gem_evict_vm - Evict all idle vmas from a vm
416 * @vm: Address space to cleanse
417 * @ww: An optional struct i915_gem_ww_ctx. If not NULL, i915_gem_evict_vm
418 * will be able to evict vma's locked by the ww as well.
419 * @busy_bo: Optional pointer to struct drm_i915_gem_object. If not NULL, then
420 * in the event i915_gem_evict_vm() is unable to trylock an object for eviction,
421 * then @busy_bo will point to it. -EBUSY is also returned. The caller must drop
422 * the vm->mutex, before trying again to acquire the contended lock. The caller
423 * also owns a reference to the object.
424 *
425 * This function evicts all vmas from a vm.
426 *
427 * This is used by the execbuf code as a last-ditch effort to defragment the
428 * address space.
429 *
430 * To clarify: This is for freeing up virtual address space, not for freeing
431 * memory in e.g. the shrinker.
432 */
433int i915_gem_evict_vm(struct i915_address_space *vm, struct i915_gem_ww_ctx *ww,
434 struct drm_i915_gem_object **busy_bo)
435{
436 int ret = 0;
437
438 lockdep_assert_held(&vm->mutex);
439 trace_i915_gem_evict_vm(vm);
440
441 /* Switch back to the default context in order to unpin
442 * the existing context objects. However, such objects only
443 * pin themselves inside the global GTT and performing the
444 * switch otherwise is ineffective.
445 */
446 if (i915_is_ggtt(vm)) {
447 ret = ggtt_flush(vm->gt);
448 if (ret)
449 return ret;
450 }
451
452 do {
453 struct i915_vma *vma, *vn;
454 LIST_HEAD(eviction_list);
455 LIST_HEAD(locked_eviction_list);
456
457 list_for_each_entry(vma, &vm->bound_list, vm_link) {
458 if (i915_vma_is_pinned(vma))
459 continue;
460
461 /*
462 * If we already own the lock, trylock fails. In case
463 * the resv is shared among multiple objects, we still
464 * need the object ref.
465 */
466 if (!i915_gem_object_get_rcu(vma->obj) ||
467 (ww && (dma_resv_locking_ctx(vma->obj->base.resv) == &ww->ctx))) {
468 __i915_vma_pin(vma);
469 list_add(&vma->evict_link, &locked_eviction_list);
470 continue;
471 }
472
473 if (!i915_gem_object_trylock(vma->obj, ww)) {
474 if (busy_bo) {
475 *busy_bo = vma->obj; /* holds ref */
476 ret = -EBUSY;
477 break;
478 }
479 i915_gem_object_put(vma->obj);
480 continue;
481 }
482
483 __i915_vma_pin(vma);
484 list_add(&vma->evict_link, &eviction_list);
485 }
486 if (list_empty(&eviction_list) && list_empty(&locked_eviction_list))
487 break;
488
489 /* Unbind locked objects first, before unlocking the eviction_list */
490 list_for_each_entry_safe(vma, vn, &locked_eviction_list, evict_link) {
491 __i915_vma_unpin(vma);
492
493 if (ret == 0) {
494 ret = __i915_vma_unbind(vma);
495 if (ret != -EINTR) /* "Get me out of here!" */
496 ret = 0;
497 }
498 if (!dying_vma(vma))
499 i915_gem_object_put(vma->obj);
500 }
501
502 list_for_each_entry_safe(vma, vn, &eviction_list, evict_link) {
503 __i915_vma_unpin(vma);
504 if (ret == 0) {
505 ret = __i915_vma_unbind(vma);
506 if (ret != -EINTR) /* "Get me out of here!" */
507 ret = 0;
508 }
509
510 i915_gem_object_unlock(vma->obj);
511 i915_gem_object_put(vma->obj);
512 }
513 } while (ret == 0);
514
515 return ret;
516}
517
518#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
519#include "selftests/i915_gem_evict.c"
520#endif