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Diffstat (limited to 'drivers/gpu/drm/i915/gem/i915_gem_shmem.c')
-rw-r--r--drivers/gpu/drm/i915/gem/i915_gem_shmem.c571
1 files changed, 571 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
new file mode 100644
index 000000000000..19d9ecdb2894
--- /dev/null
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
@@ -0,0 +1,571 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2014-2016 Intel Corporation
+ */
+
+#include <linux/pagevec.h>
+#include <linux/swap.h>
+
+#include "i915_drv.h"
+#include "i915_gem_object.h"
+#include "i915_scatterlist.h"
+
+/*
+ * Move pages to appropriate lru and release the pagevec, decrementing the
+ * ref count of those pages.
+ */
+static void check_release_pagevec(struct pagevec *pvec)
+{
+ check_move_unevictable_pages(pvec);
+ __pagevec_release(pvec);
+ cond_resched();
+}
+
+static int shmem_get_pages(struct drm_i915_gem_object *obj)
+{
+ struct drm_i915_private *i915 = to_i915(obj->base.dev);
+ const unsigned long page_count = obj->base.size / PAGE_SIZE;
+ unsigned long i;
+ struct address_space *mapping;
+ struct sg_table *st;
+ struct scatterlist *sg;
+ struct sgt_iter sgt_iter;
+ struct page *page;
+ unsigned long last_pfn = 0; /* suppress gcc warning */
+ unsigned int max_segment = i915_sg_segment_size();
+ unsigned int sg_page_sizes;
+ struct pagevec pvec;
+ gfp_t noreclaim;
+ int ret;
+
+ /*
+ * Assert that the object is not currently in any GPU domain. As it
+ * wasn't in the GTT, there shouldn't be any way it could have been in
+ * a GPU cache
+ */
+ GEM_BUG_ON(obj->read_domains & I915_GEM_GPU_DOMAINS);
+ GEM_BUG_ON(obj->write_domain & I915_GEM_GPU_DOMAINS);
+
+ /*
+ * If there's no chance of allocating enough pages for the whole
+ * object, bail early.
+ */
+ if (page_count > totalram_pages())
+ return -ENOMEM;
+
+ st = kmalloc(sizeof(*st), GFP_KERNEL);
+ if (!st)
+ return -ENOMEM;
+
+rebuild_st:
+ if (sg_alloc_table(st, page_count, GFP_KERNEL)) {
+ kfree(st);
+ return -ENOMEM;
+ }
+
+ /*
+ * Get the list of pages out of our struct file. They'll be pinned
+ * at this point until we release them.
+ *
+ * Fail silently without starting the shrinker
+ */
+ mapping = obj->base.filp->f_mapping;
+ mapping_set_unevictable(mapping);
+ noreclaim = mapping_gfp_constraint(mapping, ~__GFP_RECLAIM);
+ noreclaim |= __GFP_NORETRY | __GFP_NOWARN;
+
+ sg = st->sgl;
+ st->nents = 0;
+ sg_page_sizes = 0;
+ for (i = 0; i < page_count; i++) {
+ const unsigned int shrink[] = {
+ I915_SHRINK_BOUND | I915_SHRINK_UNBOUND,
+ 0,
+ }, *s = shrink;
+ gfp_t gfp = noreclaim;
+
+ do {
+ cond_resched();
+ page = shmem_read_mapping_page_gfp(mapping, i, gfp);
+ if (!IS_ERR(page))
+ break;
+
+ if (!*s) {
+ ret = PTR_ERR(page);
+ goto err_sg;
+ }
+
+ i915_gem_shrink(i915, 2 * page_count, NULL, *s++);
+
+ /*
+ * We've tried hard to allocate the memory by reaping
+ * our own buffer, now let the real VM do its job and
+ * go down in flames if truly OOM.
+ *
+ * However, since graphics tend to be disposable,
+ * defer the oom here by reporting the ENOMEM back
+ * to userspace.
+ */
+ if (!*s) {
+ /* reclaim and warn, but no oom */
+ gfp = mapping_gfp_mask(mapping);
+
+ /*
+ * Our bo are always dirty and so we require
+ * kswapd to reclaim our pages (direct reclaim
+ * does not effectively begin pageout of our
+ * buffers on its own). However, direct reclaim
+ * only waits for kswapd when under allocation
+ * congestion. So as a result __GFP_RECLAIM is
+ * unreliable and fails to actually reclaim our
+ * dirty pages -- unless you try over and over
+ * again with !__GFP_NORETRY. However, we still
+ * want to fail this allocation rather than
+ * trigger the out-of-memory killer and for
+ * this we want __GFP_RETRY_MAYFAIL.
+ */
+ gfp |= __GFP_RETRY_MAYFAIL;
+ }
+ } while (1);
+
+ if (!i ||
+ sg->length >= max_segment ||
+ page_to_pfn(page) != last_pfn + 1) {
+ if (i) {
+ sg_page_sizes |= sg->length;
+ sg = sg_next(sg);
+ }
+ st->nents++;
+ sg_set_page(sg, page, PAGE_SIZE, 0);
+ } else {
+ sg->length += PAGE_SIZE;
+ }
+ last_pfn = page_to_pfn(page);
+
+ /* Check that the i965g/gm workaround works. */
+ WARN_ON((gfp & __GFP_DMA32) && (last_pfn >= 0x00100000UL));
+ }
+ if (sg) { /* loop terminated early; short sg table */
+ sg_page_sizes |= sg->length;
+ sg_mark_end(sg);
+ }
+
+ /* Trim unused sg entries to avoid wasting memory. */
+ i915_sg_trim(st);
+
+ ret = i915_gem_gtt_prepare_pages(obj, st);
+ if (ret) {
+ /*
+ * DMA remapping failed? One possible cause is that
+ * it could not reserve enough large entries, asking
+ * for PAGE_SIZE chunks instead may be helpful.
+ */
+ if (max_segment > PAGE_SIZE) {
+ for_each_sgt_page(page, sgt_iter, st)
+ put_page(page);
+ sg_free_table(st);
+
+ max_segment = PAGE_SIZE;
+ goto rebuild_st;
+ } else {
+ dev_warn(&i915->drm.pdev->dev,
+ "Failed to DMA remap %lu pages\n",
+ page_count);
+ goto err_pages;
+ }
+ }
+
+ if (i915_gem_object_needs_bit17_swizzle(obj))
+ i915_gem_object_do_bit_17_swizzle(obj, st);
+
+ __i915_gem_object_set_pages(obj, st, sg_page_sizes);
+
+ return 0;
+
+err_sg:
+ sg_mark_end(sg);
+err_pages:
+ mapping_clear_unevictable(mapping);
+ pagevec_init(&pvec);
+ for_each_sgt_page(page, sgt_iter, st) {
+ if (!pagevec_add(&pvec, page))
+ check_release_pagevec(&pvec);
+ }
+ if (pagevec_count(&pvec))
+ check_release_pagevec(&pvec);
+ sg_free_table(st);
+ kfree(st);
+
+ /*
+ * shmemfs first checks if there is enough memory to allocate the page
+ * and reports ENOSPC should there be insufficient, along with the usual
+ * ENOMEM for a genuine allocation failure.
+ *
+ * We use ENOSPC in our driver to mean that we have run out of aperture
+ * space and so want to translate the error from shmemfs back to our
+ * usual understanding of ENOMEM.
+ */
+ if (ret == -ENOSPC)
+ ret = -ENOMEM;
+
+ return ret;
+}
+
+static void
+shmem_truncate(struct drm_i915_gem_object *obj)
+{
+ /*
+ * Our goal here is to return as much of the memory as
+ * is possible back to the system as we are called from OOM.
+ * To do this we must instruct the shmfs to drop all of its
+ * backing pages, *now*.
+ */
+ shmem_truncate_range(file_inode(obj->base.filp), 0, (loff_t)-1);
+ obj->mm.madv = __I915_MADV_PURGED;
+ obj->mm.pages = ERR_PTR(-EFAULT);
+}
+
+static void
+shmem_writeback(struct drm_i915_gem_object *obj)
+{
+ struct address_space *mapping;
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_NONE,
+ .nr_to_write = SWAP_CLUSTER_MAX,
+ .range_start = 0,
+ .range_end = LLONG_MAX,
+ .for_reclaim = 1,
+ };
+ unsigned long i;
+
+ /*
+ * Leave mmapings intact (GTT will have been revoked on unbinding,
+ * leaving only CPU mmapings around) and add those pages to the LRU
+ * instead of invoking writeback so they are aged and paged out
+ * as normal.
+ */
+ mapping = obj->base.filp->f_mapping;
+
+ /* Begin writeback on each dirty page */
+ for (i = 0; i < obj->base.size >> PAGE_SHIFT; i++) {
+ struct page *page;
+
+ page = find_lock_entry(mapping, i);
+ if (!page || xa_is_value(page))
+ continue;
+
+ if (!page_mapped(page) && clear_page_dirty_for_io(page)) {
+ int ret;
+
+ SetPageReclaim(page);
+ ret = mapping->a_ops->writepage(page, &wbc);
+ if (!PageWriteback(page))
+ ClearPageReclaim(page);
+ if (!ret)
+ goto put;
+ }
+ unlock_page(page);
+put:
+ put_page(page);
+ }
+}
+
+void
+__i915_gem_object_release_shmem(struct drm_i915_gem_object *obj,
+ struct sg_table *pages,
+ bool needs_clflush)
+{
+ GEM_BUG_ON(obj->mm.madv == __I915_MADV_PURGED);
+
+ if (obj->mm.madv == I915_MADV_DONTNEED)
+ obj->mm.dirty = false;
+
+ if (needs_clflush &&
+ (obj->read_domains & I915_GEM_DOMAIN_CPU) == 0 &&
+ !(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_READ))
+ drm_clflush_sg(pages);
+
+ __start_cpu_write(obj);
+}
+
+static void
+shmem_put_pages(struct drm_i915_gem_object *obj, struct sg_table *pages)
+{
+ struct sgt_iter sgt_iter;
+ struct pagevec pvec;
+ struct page *page;
+
+ __i915_gem_object_release_shmem(obj, pages, true);
+
+ i915_gem_gtt_finish_pages(obj, pages);
+
+ if (i915_gem_object_needs_bit17_swizzle(obj))
+ i915_gem_object_save_bit_17_swizzle(obj, pages);
+
+ mapping_clear_unevictable(file_inode(obj->base.filp)->i_mapping);
+
+ pagevec_init(&pvec);
+ for_each_sgt_page(page, sgt_iter, pages) {
+ if (obj->mm.dirty)
+ set_page_dirty(page);
+
+ if (obj->mm.madv == I915_MADV_WILLNEED)
+ mark_page_accessed(page);
+
+ if (!pagevec_add(&pvec, page))
+ check_release_pagevec(&pvec);
+ }
+ if (pagevec_count(&pvec))
+ check_release_pagevec(&pvec);
+ obj->mm.dirty = false;
+
+ sg_free_table(pages);
+ kfree(pages);
+}
+
+static int
+shmem_pwrite(struct drm_i915_gem_object *obj,
+ const struct drm_i915_gem_pwrite *arg)
+{
+ struct address_space *mapping = obj->base.filp->f_mapping;
+ char __user *user_data = u64_to_user_ptr(arg->data_ptr);
+ u64 remain, offset;
+ unsigned int pg;
+
+ /* Caller already validated user args */
+ GEM_BUG_ON(!access_ok(user_data, arg->size));
+
+ /*
+ * Before we instantiate/pin the backing store for our use, we
+ * can prepopulate the shmemfs filp efficiently using a write into
+ * the pagecache. We avoid the penalty of instantiating all the
+ * pages, important if the user is just writing to a few and never
+ * uses the object on the GPU, and using a direct write into shmemfs
+ * allows it to avoid the cost of retrieving a page (either swapin
+ * or clearing-before-use) before it is overwritten.
+ */
+ if (i915_gem_object_has_pages(obj))
+ return -ENODEV;
+
+ if (obj->mm.madv != I915_MADV_WILLNEED)
+ return -EFAULT;
+
+ /*
+ * Before the pages are instantiated the object is treated as being
+ * in the CPU domain. The pages will be clflushed as required before
+ * use, and we can freely write into the pages directly. If userspace
+ * races pwrite with any other operation; corruption will ensue -
+ * that is userspace's prerogative!
+ */
+
+ remain = arg->size;
+ offset = arg->offset;
+ pg = offset_in_page(offset);
+
+ do {
+ unsigned int len, unwritten;
+ struct page *page;
+ void *data, *vaddr;
+ int err;
+ char c;
+
+ len = PAGE_SIZE - pg;
+ if (len > remain)
+ len = remain;
+
+ /* Prefault the user page to reduce potential recursion */
+ err = __get_user(c, user_data);
+ if (err)
+ return err;
+
+ err = __get_user(c, user_data + len - 1);
+ if (err)
+ return err;
+
+ err = pagecache_write_begin(obj->base.filp, mapping,
+ offset, len, 0,
+ &page, &data);
+ if (err < 0)
+ return err;
+
+ vaddr = kmap_atomic(page);
+ unwritten = __copy_from_user_inatomic(vaddr + pg,
+ user_data,
+ len);
+ kunmap_atomic(vaddr);
+
+ err = pagecache_write_end(obj->base.filp, mapping,
+ offset, len, len - unwritten,
+ page, data);
+ if (err < 0)
+ return err;
+
+ /* We don't handle -EFAULT, leave it to the caller to check */
+ if (unwritten)
+ return -ENODEV;
+
+ remain -= len;
+ user_data += len;
+ offset += len;
+ pg = 0;
+ } while (remain);
+
+ return 0;
+}
+
+const struct drm_i915_gem_object_ops i915_gem_shmem_ops = {
+ .flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
+ I915_GEM_OBJECT_IS_SHRINKABLE,
+
+ .get_pages = shmem_get_pages,
+ .put_pages = shmem_put_pages,
+ .truncate = shmem_truncate,
+ .writeback = shmem_writeback,
+
+ .pwrite = shmem_pwrite,
+};
+
+static int create_shmem(struct drm_i915_private *i915,
+ struct drm_gem_object *obj,
+ size_t size)
+{
+ unsigned long flags = VM_NORESERVE;
+ struct file *filp;
+
+ drm_gem_private_object_init(&i915->drm, obj, size);
+
+ if (i915->mm.gemfs)
+ filp = shmem_file_setup_with_mnt(i915->mm.gemfs, "i915", size,
+ flags);
+ else
+ filp = shmem_file_setup("i915", size, flags);
+ if (IS_ERR(filp))
+ return PTR_ERR(filp);
+
+ obj->filp = filp;
+ return 0;
+}
+
+struct drm_i915_gem_object *
+i915_gem_object_create_shmem(struct drm_i915_private *i915, u64 size)
+{
+ struct drm_i915_gem_object *obj;
+ struct address_space *mapping;
+ unsigned int cache_level;
+ gfp_t mask;
+ int ret;
+
+ /* There is a prevalence of the assumption that we fit the object's
+ * page count inside a 32bit _signed_ variable. Let's document this and
+ * catch if we ever need to fix it. In the meantime, if you do spot
+ * such a local variable, please consider fixing!
+ */
+ if (size >> PAGE_SHIFT > INT_MAX)
+ return ERR_PTR(-E2BIG);
+
+ if (overflows_type(size, obj->base.size))
+ return ERR_PTR(-E2BIG);
+
+ obj = i915_gem_object_alloc();
+ if (!obj)
+ return ERR_PTR(-ENOMEM);
+
+ ret = create_shmem(i915, &obj->base, size);
+ if (ret)
+ goto fail;
+
+ mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
+ if (IS_I965GM(i915) || IS_I965G(i915)) {
+ /* 965gm cannot relocate objects above 4GiB. */
+ mask &= ~__GFP_HIGHMEM;
+ mask |= __GFP_DMA32;
+ }
+
+ mapping = obj->base.filp->f_mapping;
+ mapping_set_gfp_mask(mapping, mask);
+ GEM_BUG_ON(!(mapping_gfp_mask(mapping) & __GFP_RECLAIM));
+
+ i915_gem_object_init(obj, &i915_gem_shmem_ops);
+
+ obj->write_domain = I915_GEM_DOMAIN_CPU;
+ obj->read_domains = I915_GEM_DOMAIN_CPU;
+
+ if (HAS_LLC(i915))
+ /* On some devices, we can have the GPU use the LLC (the CPU
+ * cache) for about a 10% performance improvement
+ * compared to uncached. Graphics requests other than
+ * display scanout are coherent with the CPU in
+ * accessing this cache. This means in this mode we
+ * don't need to clflush on the CPU side, and on the
+ * GPU side we only need to flush internal caches to
+ * get data visible to the CPU.
+ *
+ * However, we maintain the display planes as UC, and so
+ * need to rebind when first used as such.
+ */
+ cache_level = I915_CACHE_LLC;
+ else
+ cache_level = I915_CACHE_NONE;
+
+ i915_gem_object_set_cache_coherency(obj, cache_level);
+
+ trace_i915_gem_object_create(obj);
+
+ return obj;
+
+fail:
+ i915_gem_object_free(obj);
+ return ERR_PTR(ret);
+}
+
+/* Allocate a new GEM object and fill it with the supplied data */
+struct drm_i915_gem_object *
+i915_gem_object_create_shmem_from_data(struct drm_i915_private *dev_priv,
+ const void *data, size_t size)
+{
+ struct drm_i915_gem_object *obj;
+ struct file *file;
+ size_t offset;
+ int err;
+
+ obj = i915_gem_object_create_shmem(dev_priv, round_up(size, PAGE_SIZE));
+ if (IS_ERR(obj))
+ return obj;
+
+ GEM_BUG_ON(obj->write_domain != I915_GEM_DOMAIN_CPU);
+
+ file = obj->base.filp;
+ offset = 0;
+ do {
+ unsigned int len = min_t(typeof(size), size, PAGE_SIZE);
+ struct page *page;
+ void *pgdata, *vaddr;
+
+ err = pagecache_write_begin(file, file->f_mapping,
+ offset, len, 0,
+ &page, &pgdata);
+ if (err < 0)
+ goto fail;
+
+ vaddr = kmap(page);
+ memcpy(vaddr, data, len);
+ kunmap(page);
+
+ err = pagecache_write_end(file, file->f_mapping,
+ offset, len, len,
+ page, pgdata);
+ if (err < 0)
+ goto fail;
+
+ size -= len;
+ data += len;
+ offset += len;
+ } while (size);
+
+ return obj;
+
+fail:
+ i915_gem_object_put(obj);
+ return ERR_PTR(err);
+}
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