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 
36 static bool
37 mark_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  * @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  * @mappable: whether the free space must be mappable
57  * @nonblocking: whether evicting active objects is allowed or not
58  *
59  * This function will try to evict vmas until a free space satisfying the
60  * requirements is found. Callers must check first whether any such hole exists
61  * already before calling this function.
62  *
63  * This function is used by the object/vma binding code.
64  *
65  * To clarify: This is for freeing up virtual address space, not for freeing
66  * memory in e.g. the shrinker.
67  */
68 int
69 i915_gem_evict_something(struct drm_device *dev, struct i915_address_space *vm,
70 			 int min_size, unsigned alignment, unsigned cache_level,
71 			 unsigned flags)
72 {
73 	struct drm_i915_private *dev_priv = dev->dev_private;
74 	struct list_head eviction_list, unwind_list;
75 	struct i915_vma *vma;
76 	int ret = 0;
77 	int pass = 0;
78 
79 	trace_i915_gem_evict(dev, min_size, alignment, flags);
80 
81 	/*
82 	 * The goal is to evict objects and amalgamate space in LRU order.
83 	 * The oldest idle objects reside on the inactive list, which is in
84 	 * retirement order. The next objects to retire are those on the (per
85 	 * ring) active list that do not have an outstanding flush. Once the
86 	 * hardware reports completion (the seqno is updated after the
87 	 * batchbuffer has been finished) the clean buffer objects would
88 	 * be retired to the inactive list. Any dirty objects would be added
89 	 * to the tail of the flushing list. So after processing the clean
90 	 * active objects we need to emit a MI_FLUSH to retire the flushing
91 	 * list, hence the retirement order of the flushing list is in
92 	 * advance of the dirty objects on the active lists.
93 	 *
94 	 * The retirement sequence is thus:
95 	 *   1. Inactive objects (already retired)
96 	 *   2. Clean active objects
97 	 *   3. Flushing list
98 	 *   4. Dirty active objects.
99 	 *
100 	 * On each list, the oldest objects lie at the HEAD with the freshest
101 	 * object on the TAIL.
102 	 */
103 
104 	INIT_LIST_HEAD(&unwind_list);
105 	if (flags & PIN_MAPPABLE) {
106 		BUG_ON(!i915_is_ggtt(vm));
107 		drm_mm_init_scan_with_range(&vm->mm, min_size,
108 					    alignment, cache_level, 0,
109 					    dev_priv->gtt.mappable_end);
110 	} else
111 		drm_mm_init_scan(&vm->mm, min_size, alignment, cache_level);
112 
113 search_again:
114 	/* First see if there is a large enough contiguous idle region... */
115 	list_for_each_entry(vma, &vm->inactive_list, mm_list) {
116 		if (mark_free(vma, &unwind_list))
117 			goto found;
118 	}
119 
120 	if (flags & PIN_NONBLOCK)
121 		goto none;
122 
123 	/* Now merge in the soon-to-be-expired objects... */
124 	list_for_each_entry(vma, &vm->active_list, mm_list) {
125 		if (mark_free(vma, &unwind_list))
126 			goto found;
127 	}
128 
129 none:
130 	/* Nothing found, clean up and bail out! */
131 	while (!list_empty(&unwind_list)) {
132 		vma = list_first_entry(&unwind_list,
133 				       struct i915_vma,
134 				       exec_list);
135 		ret = drm_mm_scan_remove_block(&vma->node);
136 		BUG_ON(ret);
137 
138 		list_del_init(&vma->exec_list);
139 	}
140 
141 	/* Can we unpin some objects such as idle hw contents,
142 	 * or pending flips?
143 	 */
144 	if (flags & PIN_NONBLOCK)
145 		return -ENOSPC;
146 
147 	/* Only idle the GPU and repeat the search once */
148 	if (pass++ == 0) {
149 		ret = i915_gpu_idle(dev);
150 		if (ret)
151 			return ret;
152 
153 		i915_gem_retire_requests(dev);
154 		goto search_again;
155 	}
156 
157 	/* If we still have pending pageflip completions, drop
158 	 * back to userspace to give our workqueues time to
159 	 * acquire our locks and unpin the old scanouts.
160 	 */
161 	return intel_has_pending_fb_unpin(dev) ? -EAGAIN : -ENOSPC;
162 
163 found:
164 	/* drm_mm doesn't allow any other other operations while
165 	 * scanning, therefore store to be evicted objects on a
166 	 * temporary list. */
167 	INIT_LIST_HEAD(&eviction_list);
168 	while (!list_empty(&unwind_list)) {
169 		vma = list_first_entry(&unwind_list,
170 				       struct i915_vma,
171 				       exec_list);
172 		if (drm_mm_scan_remove_block(&vma->node)) {
173 			list_move(&vma->exec_list, &eviction_list);
174 			drm_gem_object_reference(&vma->obj->base);
175 			continue;
176 		}
177 		list_del_init(&vma->exec_list);
178 	}
179 
180 	/* Unbinding will emit any required flushes */
181 	while (!list_empty(&eviction_list)) {
182 		struct drm_gem_object *obj;
183 		vma = list_first_entry(&eviction_list,
184 				       struct i915_vma,
185 				       exec_list);
186 
187 		obj =  &vma->obj->base;
188 		list_del_init(&vma->exec_list);
189 		if (ret == 0)
190 			ret = i915_vma_unbind(vma);
191 
192 		drm_gem_object_unreference(obj);
193 	}
194 
195 	return ret;
196 }
197 
198 /**
199  * i915_gem_evict_vm - Evict all idle vmas from a vm
200  *
201  * @vm: Address space to cleanse
202  * @do_idle: Boolean directing whether to idle first.
203  *
204  * This function evicts all idles vmas from a vm. If all unpinned vmas should be
205  * evicted the @do_idle needs to be set to true.
206  *
207  * This is used by the execbuf code as a last-ditch effort to defragment the
208  * address space.
209  *
210  * To clarify: This is for freeing up virtual address space, not for freeing
211  * memory in e.g. the shrinker.
212  */
213 int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)
214 {
215 	struct i915_vma *vma, *next;
216 	int ret;
217 
218 	trace_i915_gem_evict_vm(vm);
219 
220 	if (do_idle) {
221 		ret = i915_gpu_idle(vm->dev);
222 		if (ret)
223 			return ret;
224 
225 		i915_gem_retire_requests(vm->dev);
226 	}
227 
228 	list_for_each_entry_safe(vma, next, &vm->inactive_list, mm_list)
229 		if (vma->pin_count == 0)
230 			WARN_ON(i915_vma_unbind(vma));
231 
232 	return 0;
233 }
234 
235 /**
236  * i915_gem_evict_everything - Try to evict all objects
237  * @dev: Device to evict objects for
238  *
239  * This functions tries to evict all gem objects from all address spaces. Used
240  * by the shrinker as a last-ditch effort and for suspend, before releasing the
241  * backing storage of all unbound objects.
242  */
243 int
244 i915_gem_evict_everything(struct drm_device *dev)
245 {
246 	struct drm_i915_private *dev_priv = dev->dev_private;
247 	struct i915_address_space *vm;
248 	bool lists_empty = true;
249 	int ret;
250 
251 	list_for_each_entry(vm, &dev_priv->vm_list, global_link) {
252 		lists_empty = (list_empty(&vm->inactive_list) &&
253 			       list_empty(&vm->active_list));
254 		if (!lists_empty)
255 			lists_empty = false;
256 	}
257 
258 	if (lists_empty)
259 		return -ENOSPC;
260 
261 	trace_i915_gem_evict_everything(dev);
262 
263 	/* The gpu_idle will flush everything in the write domain to the
264 	 * active list. Then we must move everything off the active list
265 	 * with retire requests.
266 	 */
267 	ret = i915_gpu_idle(dev);
268 	if (ret)
269 		return ret;
270 
271 	i915_gem_retire_requests(dev);
272 
273 	/* Having flushed everything, unbind() should never raise an error */
274 	list_for_each_entry(vm, &dev_priv->vm_list, global_link)
275 		WARN_ON(i915_gem_evict_vm(vm, false));
276 
277 	return 0;
278 }
279