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, mm_list) {
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, mm_list) {
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
202/**
203 * i915_gem_evict_vm - Evict all idle vmas from a vm
204 * @vm: Address space to cleanse
205 * @do_idle: Boolean directing whether to idle first.
206 *
207 * This function evicts all idles vmas from a vm. If all unpinned vmas should be
208 * evicted the @do_idle needs to be set to true.
209 *
210 * This is used by the execbuf code as a last-ditch effort to defragment the
211 * address space.
212 *
213 * To clarify: This is for freeing up virtual address space, not for freeing
214 * memory in e.g. the shrinker.
215 */
216int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)
217{
218	struct i915_vma *vma, *next;
219	int ret;
220
221	WARN_ON(!mutex_is_locked(&vm->dev->struct_mutex));
222	trace_i915_gem_evict_vm(vm);
223
224	if (do_idle) {
225		ret = i915_gpu_idle(vm->dev);
226		if (ret)
227			return ret;
228
229		i915_gem_retire_requests(vm->dev);
230
231		WARN_ON(!list_empty(&vm->active_list));
232	}
233
234	list_for_each_entry_safe(vma, next, &vm->inactive_list, mm_list)
235		if (vma->pin_count == 0)
236			WARN_ON(i915_vma_unbind(vma));
237
238	return 0;
239}
240
241/**
242 * i915_gem_evict_everything - Try to evict all objects
243 * @dev: Device to evict objects for
244 *
245 * This functions tries to evict all gem objects from all address spaces. Used
246 * by the shrinker as a last-ditch effort and for suspend, before releasing the
247 * backing storage of all unbound objects.
248 */
249int
250i915_gem_evict_everything(struct drm_device *dev)
251{
252	struct drm_i915_private *dev_priv = dev->dev_private;
253	struct i915_address_space *vm, *v;
254	bool lists_empty = true;
255	int ret;
256
257	list_for_each_entry(vm, &dev_priv->vm_list, global_link) {
258		lists_empty = (list_empty(&vm->inactive_list) &&
259			       list_empty(&vm->active_list));
260		if (!lists_empty)
261			lists_empty = false;
262	}
263
264	if (lists_empty)
265		return -ENOSPC;
266
267	trace_i915_gem_evict_everything(dev);
268
269	/* The gpu_idle will flush everything in the write domain to the
270	 * active list. Then we must move everything off the active list
271	 * with retire requests.
272	 */
273	ret = i915_gpu_idle(dev);
274	if (ret)
275		return ret;
276
277	i915_gem_retire_requests(dev);
278
279	/* Having flushed everything, unbind() should never raise an error */
280	list_for_each_entry_safe(vm, v, &dev_priv->vm_list, global_link)
281		WARN_ON(i915_gem_evict_vm(vm, false));
282
283	return 0;
284}
285