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>
13 #include "i915_gem_object.h"
14 #include "i915_scatterlist.h"
15 #include "i915_utils.h"
17 #define QUIET (__GFP_NORETRY | __GFP_NOWARN)
18 #define MAYFAIL (__GFP_RETRY_MAYFAIL | __GFP_NOWARN)
20 static void internal_free_pages(struct sg_table *st)
22 struct scatterlist *sg;
24 for (sg = st->sgl; sg; sg = __sg_next(sg)) {
26 __free_pages(sg_page(sg), get_order(sg->length));
33 static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
35 struct drm_i915_private *i915 = to_i915(obj->base.dev);
37 struct scatterlist *sg;
38 unsigned int sg_page_sizes;
43 max_order = MAX_ORDER;
45 if (is_swiotlb_active(obj->base.dev->dev)) {
46 unsigned int max_segment;
48 max_segment = swiotlb_max_segment();
50 max_segment = max_t(unsigned int, max_segment,
51 PAGE_SIZE) >> PAGE_SHIFT;
52 max_order = min(max_order, ilog2(max_segment));
57 gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_RECLAIMABLE;
58 if (IS_I965GM(i915) || IS_I965G(i915)) {
59 /* 965gm cannot relocate objects above 4GiB. */
60 gfp &= ~__GFP_HIGHMEM;
65 st = kmalloc(sizeof(*st), GFP_KERNEL);
69 npages = obj->base.size / PAGE_SIZE;
70 if (sg_alloc_table(st, npages, GFP_KERNEL)) {
80 int order = min(fls(npages) - 1, max_order);
84 page = alloc_pages(gfp | (order ? QUIET : MAYFAIL),
91 /* Limit subsequent allocations as well */
95 sg_set_page(sg, page, PAGE_SIZE << order, 0);
96 sg_page_sizes |= PAGE_SIZE << order;
108 if (i915_gem_gtt_prepare_pages(obj, st)) {
109 /* Failed to dma-map try again with single page sg segments */
110 if (get_order(st->sgl->length)) {
111 internal_free_pages(st);
118 __i915_gem_object_set_pages(obj, st, sg_page_sizes);
123 sg_set_page(sg, NULL, 0, 0);
125 internal_free_pages(st);
130 static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj,
131 struct sg_table *pages)
133 i915_gem_gtt_finish_pages(obj, pages);
134 internal_free_pages(pages);
136 obj->mm.dirty = false;
138 __start_cpu_write(obj);
141 static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
142 .name = "i915_gem_object_internal",
143 .flags = I915_GEM_OBJECT_IS_SHRINKABLE,
144 .get_pages = i915_gem_object_get_pages_internal,
145 .put_pages = i915_gem_object_put_pages_internal,
149 * i915_gem_object_create_internal: create an object with volatile pages
150 * @i915: the i915 device
151 * @size: the size in bytes of backing storage to allocate for the object
153 * Creates a new object that wraps some internal memory for private use.
154 * This object is not backed by swappable storage, and as such its contents
155 * are volatile and only valid whilst pinned. If the object is reaped by the
156 * shrinker, its pages and data will be discarded. Equally, it is not a full
157 * GEM object and so not valid for access from userspace. This makes it useful
158 * for hardware interfaces like ringbuffers (which are pinned from the time
159 * the request is written to the time the hardware stops accessing it), but
160 * not for contexts (which need to be preserved when not active for later
161 * reuse). Note that it is not cleared upon allocation.
163 struct drm_i915_gem_object *
164 i915_gem_object_create_internal(struct drm_i915_private *i915,
167 static struct lock_class_key lock_class;
168 struct drm_i915_gem_object *obj;
169 unsigned int cache_level;
172 GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE));
174 if (overflows_type(size, obj->base.size))
175 return ERR_PTR(-E2BIG);
177 obj = i915_gem_object_alloc();
179 return ERR_PTR(-ENOMEM);
181 drm_gem_private_object_init(&i915->drm, &obj->base, size);
182 i915_gem_object_init(obj, &i915_gem_object_internal_ops, &lock_class, 0);
183 obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE;
186 * Mark the object as volatile, such that the pages are marked as
187 * dontneed whilst they are still pinned. As soon as they are unpinned
188 * they are allowed to be reaped by the shrinker, and the caller is
189 * expected to repopulate - the contents of this object are only valid
190 * whilst active and pinned.
192 i915_gem_object_set_volatile(obj);
194 obj->read_domains = I915_GEM_DOMAIN_CPU;
195 obj->write_domain = I915_GEM_DOMAIN_CPU;
197 cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
198 i915_gem_object_set_cache_coherency(obj, cache_level);