[PATCH v2 3/7] drm/i915/ttm: add tt shmem backend
Matthew Auld
matthew.auld at intel.com
Tue Sep 14 08:50:29 UTC 2021
For cached objects we can allocate our pages directly in shmem. This
should make it possible(in a later patch) to utilise the existing
i915-gem shrinker code for such objects. For now this is still disabled.
Signed-off-by: Matthew Auld <matthew.auld at intel.com>
Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Cc: Christian König <christian.koenig at amd.com>
---
drivers/gpu/drm/i915/gem/i915_gem_object.h | 8 +
drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 14 +-
drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 214 ++++++++++++++++++---
3 files changed, 206 insertions(+), 30 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index 48112b9d76df..561d6bd0a5c9 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -618,6 +618,14 @@ int i915_gem_object_wait_migration(struct drm_i915_gem_object *obj,
bool i915_gem_object_placement_possible(struct drm_i915_gem_object *obj,
enum intel_memory_type type);
+struct sg_table *shmem_alloc_st(struct drm_i915_private *i915,
+ size_t size, struct intel_memory_region *mr,
+ struct address_space *mapping,
+ unsigned int max_segment);
+void shmem_free_st(struct sg_table *st, struct address_space *mapping,
+ bool dirty, bool backup);
+void __shmem_writeback(size_t size, struct address_space *mapping);
+
#ifdef CONFIG_MMU_NOTIFIER
static inline bool
i915_gem_object_is_userptr(struct drm_i915_gem_object *obj)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
index 36b711ae9e28..19e55cc29a15 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
@@ -25,8 +25,8 @@ static void check_release_pagevec(struct pagevec *pvec)
cond_resched();
}
-static void shmem_free_st(struct sg_table *st, struct address_space *mapping,
- bool dirty, bool backup)
+void shmem_free_st(struct sg_table *st, struct address_space *mapping,
+ bool dirty, bool backup)
{
struct sgt_iter sgt_iter;
struct pagevec pvec;
@@ -52,10 +52,10 @@ static void shmem_free_st(struct sg_table *st, struct address_space *mapping,
kfree(st);
}
-static struct sg_table *shmem_alloc_st(struct drm_i915_private *i915,
- size_t size, struct intel_memory_region *mr,
- struct address_space *mapping,
- unsigned int max_segment)
+struct sg_table *shmem_alloc_st(struct drm_i915_private *i915,
+ size_t size, struct intel_memory_region *mr,
+ struct address_space *mapping,
+ unsigned int max_segment)
{
const unsigned long page_count = size / PAGE_SIZE;
unsigned long i;
@@ -300,7 +300,7 @@ shmem_truncate(struct drm_i915_gem_object *obj)
obj->mm.pages = ERR_PTR(-EFAULT);
}
-static void __shmem_writeback(size_t size, struct address_space *mapping)
+void __shmem_writeback(size_t size, struct address_space *mapping)
{
struct writeback_control wbc = {
.sync_mode = WB_SYNC_NONE,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index aefaf9293005..e60e538afcd9 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -37,6 +37,9 @@
* @ttm: The base TTM page vector.
* @dev: The struct device used for dma mapping and unmapping.
* @cached_st: The cached scatter-gather table.
+ * @obj: The GEM object. Should be valid while we have a valid bo->ttm.
+ * @filp: The shmem file, if using shmem backend.
+ * @backup: Swap out the pages when unpopulating, if using shmem backend.
*
* Note that DMA may be going on right up to the point where the page-
* vector is unpopulated in delayed destroy. Hence keep the
@@ -48,6 +51,9 @@ struct i915_ttm_tt {
struct ttm_tt ttm;
struct device *dev;
struct sg_table *cached_st;
+ struct drm_i915_gem_object *obj;
+ struct file *filp;
+ bool backup;
};
static const struct ttm_place sys_placement_flags = {
@@ -167,12 +173,105 @@ i915_ttm_placement_from_obj(const struct drm_i915_gem_object *obj,
placement->busy_placement = busy;
}
+static int i915_ttm_tt_shmem_populate(struct ttm_device *bdev,
+ struct ttm_tt *ttm,
+ struct ttm_operation_ctx *ctx)
+{
+ struct drm_i915_private *i915 = container_of(bdev, typeof(*i915), bdev);
+ struct intel_memory_region *mr = i915->mm.regions[INTEL_MEMORY_SYSTEM];
+ struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
+ const unsigned int max_segment = i915_sg_segment_size();
+ const size_t size = ttm->num_pages << PAGE_SHIFT;
+ struct drm_i915_gem_object *obj = i915_tt->obj;
+ struct file *filp = i915_tt->filp;
+ struct sgt_iter sgt_iter;
+ struct sg_table *st;
+ struct page *page;
+ unsigned long i;
+ int err;
+
+ GEM_BUG_ON(obj->mm.madv != I915_MADV_WILLNEED);
+
+ if (!filp) {
+ struct address_space *mapping;
+ gfp_t mask;
+
+ filp = shmem_file_setup("i915-shmem-tt", size, VM_NORESERVE);
+ if (IS_ERR(filp))
+ return PTR_ERR(filp);
+
+ mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
+
+ mapping = filp->f_mapping;
+ mapping_set_gfp_mask(mapping, mask);
+ GEM_BUG_ON(!(mapping_gfp_mask(mapping) & __GFP_RECLAIM));
+
+ i915_tt->filp = filp;
+ }
+
+ st = shmem_alloc_st(i915, size, mr, filp->f_mapping, max_segment);
+ if (IS_ERR(st))
+ return PTR_ERR(st);
+
+ err = dma_map_sg_attrs(i915_tt->dev,
+ st->sgl, st->nents,
+ PCI_DMA_BIDIRECTIONAL,
+ DMA_ATTR_SKIP_CPU_SYNC |
+ DMA_ATTR_NO_KERNEL_MAPPING |
+ DMA_ATTR_NO_WARN);
+ if (err <= 0) {
+ err = -EINVAL;
+ goto err_free_st;
+ }
+
+ i = 0;
+ for_each_sgt_page(page, sgt_iter, st)
+ ttm->pages[i++] = page;
+
+ if (ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)
+ ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
+
+ i915_tt->cached_st = st;
+ return 0;
+
+err_free_st:
+ shmem_free_st(st, filp->f_mapping, false, false);
+ return err;
+}
+
+static void i915_ttm_tt_shmem_unpopulate(struct ttm_tt *ttm)
+{
+ struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
+ struct drm_i915_gem_object *obj = i915_tt->obj;
+ bool backup = i915_tt->backup;
+
+ if (obj->mm.madv == I915_MADV_DONTNEED) {
+ obj->mm.dirty = false;
+ GEM_BUG_ON(backup);
+ }
+
+ dma_unmap_sg(i915_tt->dev, i915_tt->cached_st->sgl,
+ i915_tt->cached_st->nents,
+ PCI_DMA_BIDIRECTIONAL);
+
+ shmem_free_st(i915_tt->cached_st,
+ file_inode(i915_tt->filp)->i_mapping,
+ obj->mm.dirty, backup);
+ i915_tt->cached_st = NULL;
+
+ obj->mm.dirty = false;
+
+ if (backup)
+ ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
+}
+
static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
uint32_t page_flags)
{
struct ttm_resource_manager *man =
ttm_manager_type(bo->bdev, bo->resource->mem_type);
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
+ enum ttm_caching caching = i915_ttm_select_tt_caching(obj);
struct i915_ttm_tt *i915_tt;
int ret;
@@ -184,36 +283,60 @@ static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
man->use_tt)
page_flags |= TTM_PAGE_FLAG_ZERO_ALLOC;
- ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags,
- i915_ttm_select_tt_caching(obj));
- if (ret) {
- kfree(i915_tt);
- return NULL;
- }
+ if (i915_gem_object_is_shrinkable(obj) && caching == ttm_cached)
+ page_flags |= TTM_PAGE_FLAG_SHMEM;
+
+ ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching);
+ if (ret)
+ goto err_free;
i915_tt->dev = obj->base.dev->dev;
+ i915_tt->obj = obj;
return &i915_tt->ttm;
+
+err_free:
+ kfree(i915_tt);
+ return NULL;
+}
+
+static int i915_ttm_tt_populate(struct ttm_device *bdev,
+ struct ttm_tt *ttm,
+ struct ttm_operation_ctx *ctx)
+{
+ struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
+
+ if (ttm->page_flags & TTM_PAGE_FLAG_SHMEM)
+ return i915_ttm_tt_shmem_populate(bdev, ttm, ctx);
+
+ return ttm_pool_alloc(&bdev->pool, ttm, ctx);
}
static void i915_ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm)
{
struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
- if (i915_tt->cached_st) {
- dma_unmap_sgtable(i915_tt->dev, i915_tt->cached_st,
- DMA_BIDIRECTIONAL, 0);
- sg_free_table(i915_tt->cached_st);
- kfree(i915_tt->cached_st);
- i915_tt->cached_st = NULL;
+ if (ttm->page_flags & TTM_PAGE_FLAG_SHMEM) {
+ i915_ttm_tt_shmem_unpopulate(ttm);
+ } else {
+ if (i915_tt->cached_st) {
+ dma_unmap_sgtable(i915_tt->dev, i915_tt->cached_st,
+ DMA_BIDIRECTIONAL, 0);
+ sg_free_table(i915_tt->cached_st);
+ kfree(i915_tt->cached_st);
+ i915_tt->cached_st = NULL;
+ }
+ ttm_pool_free(&bdev->pool, ttm);
}
- ttm_pool_free(&bdev->pool, ttm);
}
static void i915_ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
{
struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
+ if (i915_tt->filp)
+ fput(i915_tt->filp);
+
ttm_tt_fini(ttm);
kfree(i915_tt);
}
@@ -223,6 +346,10 @@ static bool i915_ttm_eviction_valuable(struct ttm_buffer_object *bo,
{
struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
+ if (place->mem_type == TTM_PL_SYSTEM &&
+ bo->ttm && bo->ttm->page_flags & TTM_PAGE_FLAG_SHMEM)
+ return false;
+
/* Will do for now. Our pinned objects are still on TTM's LRU lists */
return i915_gem_object_evictable(obj);
}
@@ -316,9 +443,11 @@ static void i915_ttm_adjust_gem_after_move(struct drm_i915_gem_object *obj)
i915_gem_object_set_cache_coherency(obj, cache_level);
}
-static void i915_ttm_purge(struct drm_i915_gem_object *obj)
+static void i915_ttm_writeback(struct drm_i915_gem_object *obj)
{
struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
+ struct i915_ttm_tt *i915_tt =
+ container_of(bo->ttm, typeof(*i915_tt), ttm);
struct ttm_operation_ctx ctx = {
.interruptible = true,
.no_wait_gpu = false,
@@ -326,18 +455,52 @@ static void i915_ttm_purge(struct drm_i915_gem_object *obj)
struct ttm_placement place = {};
int ret;
- if (obj->mm.madv == __I915_MADV_PURGED)
+ if (!bo->ttm || !(bo->ttm->page_flags & TTM_PAGE_FLAG_SHMEM))
return;
- /* TTM's purge interface. Note that we might be reentering. */
+ i915_tt->backup = true;
ret = ttm_bo_validate(bo, &place, &ctx);
- if (!ret) {
- obj->write_domain = 0;
- obj->read_domains = 0;
- i915_ttm_adjust_gem_after_move(obj);
- i915_ttm_free_cached_io_st(obj);
- obj->mm.madv = __I915_MADV_PURGED;
+ i915_tt->backup = false;
+ if (ret)
+ return;
+
+ __shmem_writeback(obj->base.size, i915_tt->filp->f_mapping);
+}
+
+static void i915_ttm_purge(struct drm_i915_gem_object *obj)
+{
+ struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
+ struct ttm_operation_ctx ctx = {
+ .interruptible = true,
+ .no_wait_gpu = false,
+ };
+ struct ttm_placement place = {};
+
+ if (obj->mm.madv == __I915_MADV_PURGED)
+ return;
+
+ if (ttm_bo_validate(bo, &place, &ctx))
+ return;
+
+ if (bo->ttm && bo->ttm->page_flags & TTM_PAGE_FLAG_SHMEM) {
+ struct i915_ttm_tt *i915_tt =
+ container_of(bo->ttm, typeof(*i915_tt), ttm);
+
+ GEM_BUG_ON(i915_tt->backup);
+
+ if (i915_tt->filp) {
+ shmem_truncate_range(file_inode(i915_tt->filp),
+ 0, (loff_t)-1);
+ fput(i915_tt->filp);
+ i915_tt->filp = NULL;
+ }
}
+
+ obj->write_domain = 0;
+ obj->read_domains = 0;
+ i915_ttm_adjust_gem_after_move(obj);
+ i915_ttm_free_cached_io_st(obj);
+ obj->mm.madv = __I915_MADV_PURGED;
}
static void i915_ttm_swap_notify(struct ttm_buffer_object *bo)
@@ -605,6 +768,7 @@ static unsigned long i915_ttm_io_mem_pfn(struct ttm_buffer_object *bo,
static struct ttm_device_funcs i915_ttm_bo_driver = {
.ttm_tt_create = i915_ttm_tt_create,
+ .ttm_tt_populate = i915_ttm_tt_populate,
.ttm_tt_unpopulate = i915_ttm_tt_unpopulate,
.ttm_tt_destroy = i915_ttm_tt_destroy,
.eviction_valuable = i915_ttm_eviction_valuable,
@@ -678,6 +842,8 @@ static int __i915_ttm_get_pages(struct drm_i915_gem_object *obj,
return PTR_ERR(st);
__i915_gem_object_set_pages(obj, st, i915_sg_dma_sizes(st->sgl));
+ if (!bo->ttm || !(bo->ttm->page_flags & TTM_PAGE_FLAG_SHMEM))
+ i915_gem_object_make_unshrinkable(obj);
}
return ret;
@@ -874,9 +1040,12 @@ static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_ops = {
.get_pages = i915_ttm_get_pages,
.put_pages = i915_ttm_put_pages,
.truncate = i915_ttm_purge,
+ .writeback = i915_ttm_writeback,
+
.adjust_lru = i915_ttm_adjust_lru,
.delayed_free = i915_ttm_delayed_free,
.migrate = i915_ttm_migrate,
+
.mmap_offset = i915_ttm_mmap_offset,
.mmap_ops = &vm_ops_ttm,
};
@@ -918,7 +1087,6 @@ int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
drm_gem_private_object_init(&i915->drm, &obj->base, size);
i915_gem_object_init(obj, &i915_gem_ttm_obj_ops, &lock_class, flags);
i915_gem_object_init_memory_region(obj, mem);
- i915_gem_object_make_unshrinkable(obj);
INIT_RADIX_TREE(&obj->ttm.get_io_page.radix, GFP_KERNEL | __GFP_NOWARN);
mutex_init(&obj->ttm.get_io_page.lock);
bo_type = (obj->flags & I915_BO_ALLOC_USER) ? ttm_bo_type_device :
--
2.26.3
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