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git.ipfire.org Git - thirdparty/linux.git/blob - drivers/gpu/drm/i915/i915_gem_evict.c
2 * Copyright © 2008-2010 Intel Corporation
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:
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
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
24 * Eric Anholt <eric@anholt.net>
25 * Chris Wilson <chris@chris-wilson.co.uuk>
29 #include "gem/i915_gem_context.h"
30 #include "gt/intel_gt_requests.h"
33 #include "i915_trace.h"
35 I915_SELFTEST_DECLARE(static struct igt_evict_ctl
{
39 static int ggtt_flush(struct intel_gt
*gt
)
42 * Not everything in the GGTT is tracked via vma (otherwise we
43 * could evict as required with minimal stalling) so we are forced
44 * to idle the GPU and explicitly retire outstanding requests in
45 * the hopes that we can then remove contexts and the like only
46 * bound by their active reference.
48 return intel_gt_wait_for_idle(gt
, MAX_SCHEDULE_TIMEOUT
);
52 mark_free(struct drm_mm_scan
*scan
,
55 struct list_head
*unwind
)
57 if (i915_vma_is_pinned(vma
))
60 list_add(&vma
->evict_link
, unwind
);
61 return drm_mm_scan_add_block(scan
, &vma
->node
);
65 * i915_gem_evict_something - Evict vmas to make room for binding a new one
66 * @vm: address space to evict from
67 * @min_size: size of the desired free space
68 * @alignment: alignment constraint of the desired free space
69 * @color: color for the desired space
70 * @start: start (inclusive) of the range from which to evict objects
71 * @end: end (exclusive) of the range from which to evict objects
72 * @flags: additional flags to control the eviction algorithm
74 * This function will try to evict vmas until a free space satisfying the
75 * requirements is found. Callers must check first whether any such hole exists
76 * already before calling this function.
78 * This function is used by the object/vma binding code.
80 * Since this function is only used to free up virtual address space it only
81 * ignores pinned vmas, and not object where the backing storage itself is
82 * pinned. Hence obj->pages_pin_count does not protect against eviction.
84 * To clarify: This is for freeing up virtual address space, not for freeing
85 * memory in e.g. the shrinker.
88 i915_gem_evict_something(struct i915_address_space
*vm
,
89 u64 min_size
, u64 alignment
,
94 struct drm_mm_scan scan
;
95 struct list_head eviction_list
;
96 struct i915_vma
*vma
, *next
;
97 struct drm_mm_node
*node
;
98 enum drm_mm_insert_mode mode
;
99 struct i915_vma
*active
;
102 lockdep_assert_held(&vm
->mutex
);
103 trace_i915_gem_evict(vm
, min_size
, alignment
, flags
);
106 * The goal is to evict objects and amalgamate space in rough LRU order.
107 * Since both active and inactive objects reside on the same list,
108 * in a mix of creation and last scanned order, as we process the list
109 * we sort it into inactive/active, which keeps the active portion
110 * in a rough MRU order.
112 * The retirement sequence is thus:
113 * 1. Inactive objects (already retired, random order)
114 * 2. Active objects (will stall on unbinding, oldest scanned first)
116 mode
= DRM_MM_INSERT_BEST
;
117 if (flags
& PIN_HIGH
)
118 mode
= DRM_MM_INSERT_HIGH
;
119 if (flags
& PIN_MAPPABLE
)
120 mode
= DRM_MM_INSERT_LOW
;
121 drm_mm_scan_init_with_range(&scan
, &vm
->mm
,
122 min_size
, alignment
, color
,
125 intel_gt_retire_requests(vm
->gt
);
129 INIT_LIST_HEAD(&eviction_list
);
130 list_for_each_entry_safe(vma
, next
, &vm
->bound_list
, vm_link
) {
132 * We keep this list in a rough least-recently scanned order
133 * of active elements (inactive elements are cheap to reap).
134 * New entries are added to the end, and we move anything we
135 * scan to the end. The assumption is that the working set
136 * of applications is either steady state (and thanks to the
137 * userspace bo cache it almost always is) or volatile and
138 * frequently replaced after a frame, which are self-evicting!
139 * Given that assumption, the MRU order of the scan list is
140 * fairly static, and keeping it in least-recently scan order
143 * To notice when we complete one full cycle, we record the
144 * first active element seen, before moving it to the tail.
146 if (i915_vma_is_active(vma
)) {
148 if (flags
& PIN_NONBLOCK
)
151 active
= ERR_PTR(-EAGAIN
);
154 if (active
!= ERR_PTR(-EAGAIN
)) {
158 list_move_tail(&vma
->vm_link
, &vm
->bound_list
);
163 if (mark_free(&scan
, vma
, flags
, &eviction_list
))
167 /* Nothing found, clean up and bail out! */
168 list_for_each_entry_safe(vma
, next
, &eviction_list
, evict_link
) {
169 ret
= drm_mm_scan_remove_block(&scan
, &vma
->node
);
174 * Can we unpin some objects such as idle hw contents,
175 * or pending flips? But since only the GGTT has global entries
176 * such as scanouts, rinbuffers and contexts, we can skip the
177 * purge when inspecting per-process local address spaces.
179 if (!i915_is_ggtt(vm
) || flags
& PIN_NONBLOCK
)
183 * Not everything in the GGTT is tracked via VMA using
184 * i915_vma_move_to_active(), otherwise we could evict as required
185 * with minimal stalling. Instead we are forced to idle the GPU and
186 * explicitly retire outstanding requests which will then remove
187 * the pinning for active objects such as contexts and ring,
188 * enabling us to evict them on the next iteration.
190 * To ensure that all user contexts are evictable, we perform
191 * a switch to the perma-pinned kernel context. This all also gives
192 * us a termination condition, when the last retired context is
193 * the kernel's there is no more we can evict.
195 if (I915_SELFTEST_ONLY(igt_evict_ctl
.fail_if_busy
))
198 ret
= ggtt_flush(vm
->gt
);
204 flags
|= PIN_NONBLOCK
;
208 /* drm_mm doesn't allow any other other operations while
209 * scanning, therefore store to-be-evicted objects on a
210 * temporary list and take a reference for all before
211 * calling unbind (which may remove the active reference
212 * of any of our objects, thus corrupting the list).
214 list_for_each_entry_safe(vma
, next
, &eviction_list
, evict_link
) {
215 if (drm_mm_scan_remove_block(&scan
, &vma
->node
))
218 list_del(&vma
->evict_link
);
221 /* Unbinding will emit any required flushes */
223 list_for_each_entry_safe(vma
, next
, &eviction_list
, evict_link
) {
224 __i915_vma_unpin(vma
);
226 ret
= __i915_vma_unbind(vma
);
229 while (ret
== 0 && (node
= drm_mm_scan_color_evict(&scan
))) {
230 vma
= container_of(node
, struct i915_vma
, node
);
231 ret
= __i915_vma_unbind(vma
);
238 * i915_gem_evict_for_vma - Evict vmas to make room for binding a new one
239 * @vm: address space to evict from
240 * @target: range (and color) to evict for
241 * @flags: additional flags to control the eviction algorithm
243 * This function will try to evict vmas that overlap the target node.
245 * To clarify: This is for freeing up virtual address space, not for freeing
246 * memory in e.g. the shrinker.
248 int i915_gem_evict_for_node(struct i915_address_space
*vm
,
249 struct drm_mm_node
*target
,
252 LIST_HEAD(eviction_list
);
253 struct drm_mm_node
*node
;
254 u64 start
= target
->start
;
255 u64 end
= start
+ target
->size
;
256 struct i915_vma
*vma
, *next
;
259 lockdep_assert_held(&vm
->mutex
);
260 GEM_BUG_ON(!IS_ALIGNED(start
, I915_GTT_PAGE_SIZE
));
261 GEM_BUG_ON(!IS_ALIGNED(end
, I915_GTT_PAGE_SIZE
));
263 trace_i915_gem_evict_node(vm
, target
, flags
);
266 * Retire before we search the active list. Although we have
267 * reasonable accuracy in our retirement lists, we may have
268 * a stray pin (preventing eviction) that can only be resolved by
271 intel_gt_retire_requests(vm
->gt
);
273 if (i915_vm_has_cache_coloring(vm
)) {
274 /* Expand search to cover neighbouring guard pages (or lack!) */
276 start
-= I915_GTT_PAGE_SIZE
;
278 /* Always look at the page afterwards to avoid the end-of-GTT */
279 end
+= I915_GTT_PAGE_SIZE
;
281 GEM_BUG_ON(start
>= end
);
283 drm_mm_for_each_node_in_range(node
, &vm
->mm
, start
, end
) {
284 /* If we find any non-objects (!vma), we cannot evict them */
285 if (node
->color
== I915_COLOR_UNEVICTABLE
) {
290 GEM_BUG_ON(!drm_mm_node_allocated(node
));
291 vma
= container_of(node
, typeof(*vma
), node
);
294 * If we are using coloring to insert guard pages between
295 * different cache domains within the address space, we have
296 * to check whether the objects on either side of our range
297 * abutt and conflict. If they are in conflict, then we evict
298 * those as well to make room for our guard pages.
300 if (i915_vm_has_cache_coloring(vm
)) {
301 if (node
->start
+ node
->size
== target
->start
) {
302 if (node
->color
== target
->color
)
305 if (node
->start
== target
->start
+ target
->size
) {
306 if (node
->color
== target
->color
)
311 if (i915_vma_is_pinned(vma
)) {
316 if (flags
& PIN_NONBLOCK
&& i915_vma_is_active(vma
)) {
322 * Never show fear in the face of dragons!
324 * We cannot directly remove this node from within this
325 * iterator and as with i915_gem_evict_something() we employ
326 * the vma pin_count in order to prevent the action of
327 * unbinding one vma from freeing (by dropping its active
328 * reference) another in our eviction list.
331 list_add(&vma
->evict_link
, &eviction_list
);
334 list_for_each_entry_safe(vma
, next
, &eviction_list
, evict_link
) {
335 __i915_vma_unpin(vma
);
337 ret
= __i915_vma_unbind(vma
);
344 * i915_gem_evict_vm - Evict all idle vmas from a vm
345 * @vm: Address space to cleanse
347 * This function evicts all vmas from a vm.
349 * This is used by the execbuf code as a last-ditch effort to defragment the
352 * To clarify: This is for freeing up virtual address space, not for freeing
353 * memory in e.g. the shrinker.
355 int i915_gem_evict_vm(struct i915_address_space
*vm
)
359 lockdep_assert_held(&vm
->mutex
);
360 trace_i915_gem_evict_vm(vm
);
362 /* Switch back to the default context in order to unpin
363 * the existing context objects. However, such objects only
364 * pin themselves inside the global GTT and performing the
365 * switch otherwise is ineffective.
367 if (i915_is_ggtt(vm
)) {
368 ret
= ggtt_flush(vm
->gt
);
374 struct i915_vma
*vma
, *vn
;
375 LIST_HEAD(eviction_list
);
377 list_for_each_entry(vma
, &vm
->bound_list
, vm_link
) {
378 if (i915_vma_is_pinned(vma
))
382 list_add(&vma
->evict_link
, &eviction_list
);
384 if (list_empty(&eviction_list
))
388 list_for_each_entry_safe(vma
, vn
, &eviction_list
, evict_link
) {
389 __i915_vma_unpin(vma
);
391 ret
= __i915_vma_unbind(vma
);
392 if (ret
!= -EINTR
) /* "Get me out of here!" */
400 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
401 #include "selftests/i915_gem_evict.c"