2 * SPDX-License-Identifier: MIT
4 * Copyright © 2014-2016 Intel Corporation
7 #include <linux/scatterlist.h>
8 #include <linux/slab.h>
9 #include <linux/swiotlb.h>
11 #include <drm/i915_drm.h>
15 #include "i915_gem_object.h"
16 #include "i915_scatterlist.h"
17 #include "i915_utils.h"
19 #define QUIET (__GFP_NORETRY | __GFP_NOWARN)
20 #define MAYFAIL (__GFP_RETRY_MAYFAIL | __GFP_NOWARN)
22 static void internal_free_pages(struct sg_table *st)
24 struct scatterlist *sg;
26 for (sg = st->sgl; sg; sg = __sg_next(sg)) {
28 __free_pages(sg_page(sg), get_order(sg->length));
35 static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
37 struct drm_i915_private *i915 = to_i915(obj->base.dev);
39 struct scatterlist *sg;
40 unsigned int sg_page_sizes;
45 max_order = MAX_ORDER;
47 if (swiotlb_nr_tbl()) {
48 unsigned int max_segment;
50 max_segment = swiotlb_max_segment();
52 max_segment = max_t(unsigned int, max_segment,
53 PAGE_SIZE) >> PAGE_SHIFT;
54 max_order = min(max_order, ilog2(max_segment));
59 gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_RECLAIMABLE;
60 if (IS_I965GM(i915) || IS_I965G(i915)) {
61 /* 965gm cannot relocate objects above 4GiB. */
62 gfp &= ~__GFP_HIGHMEM;
67 st = kmalloc(sizeof(*st), GFP_KERNEL);
71 npages = obj->base.size / PAGE_SIZE;
72 if (sg_alloc_table(st, npages, GFP_KERNEL)) {
82 int order = min(fls(npages) - 1, max_order);
86 page = alloc_pages(gfp | (order ? QUIET : MAYFAIL),
93 /* Limit subsequent allocations as well */
97 sg_set_page(sg, page, PAGE_SIZE << order, 0);
98 sg_page_sizes |= PAGE_SIZE << order;
101 npages -= 1 << order;
110 if (i915_gem_gtt_prepare_pages(obj, st)) {
111 /* Failed to dma-map try again with single page sg segments */
112 if (get_order(st->sgl->length)) {
113 internal_free_pages(st);
120 /* Mark the pages as dontneed whilst they are still pinned. As soon
121 * as they are unpinned they are allowed to be reaped by the shrinker,
122 * and the caller is expected to repopulate - the contents of this
123 * object are only valid whilst active and pinned.
125 obj->mm.madv = I915_MADV_DONTNEED;
127 __i915_gem_object_set_pages(obj, st, sg_page_sizes);
132 sg_set_page(sg, NULL, 0, 0);
134 internal_free_pages(st);
139 static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj,
140 struct sg_table *pages)
142 i915_gem_gtt_finish_pages(obj, pages);
143 internal_free_pages(pages);
145 obj->mm.dirty = false;
146 obj->mm.madv = I915_MADV_WILLNEED;
149 static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
150 .flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
151 I915_GEM_OBJECT_IS_SHRINKABLE,
152 .get_pages = i915_gem_object_get_pages_internal,
153 .put_pages = i915_gem_object_put_pages_internal,
157 * i915_gem_object_create_internal: create an object with volatile pages
158 * @i915: the i915 device
159 * @size: the size in bytes of backing storage to allocate for the object
161 * Creates a new object that wraps some internal memory for private use.
162 * This object is not backed by swappable storage, and as such its contents
163 * are volatile and only valid whilst pinned. If the object is reaped by the
164 * shrinker, its pages and data will be discarded. Equally, it is not a full
165 * GEM object and so not valid for access from userspace. This makes it useful
166 * for hardware interfaces like ringbuffers (which are pinned from the time
167 * the request is written to the time the hardware stops accessing it), but
168 * not for contexts (which need to be preserved when not active for later
169 * reuse). Note that it is not cleared upon allocation.
171 struct drm_i915_gem_object *
172 i915_gem_object_create_internal(struct drm_i915_private *i915,
175 struct drm_i915_gem_object *obj;
176 unsigned int cache_level;
179 GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE));
181 if (overflows_type(size, obj->base.size))
182 return ERR_PTR(-E2BIG);
184 obj = i915_gem_object_alloc();
186 return ERR_PTR(-ENOMEM);
188 drm_gem_private_object_init(&i915->drm, &obj->base, size);
189 i915_gem_object_init(obj, &i915_gem_object_internal_ops);
191 obj->read_domains = I915_GEM_DOMAIN_CPU;
192 obj->write_domain = I915_GEM_DOMAIN_CPU;
194 cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
195 i915_gem_object_set_cache_coherency(obj, cache_level);