drm/i915: Move shmem object setup to its own file

Split the plain old shmem object into its own file to start decluttering
i915_gem.c

v2: Lose the confusing, hysterical raisins, suffix of _gtt.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528092956.14910-4-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/Makefile

@@ -87,7 +87,8 @@ i915-y += $(gt-y)
 # GEM (Graphics Execution Management) code
 obj-y += gem/
 gem-y += \
-	gem/i915_gem_object.o
+	gem/i915_gem_object.o \
+	gem/i915_gem_shmem.o
 i915-y += \
 	  $(gem-y) \
 	  i915_active.o \

drivers/gpu/drm/i915/gem/i915_gem_object.c

@@ -25,6 +25,7 @@
 #include "i915_drv.h"
 #include "i915_gem_object.h"
 #include "i915_globals.h"
+#include "intel_frontbuffer.h"
 
 static struct i915_global_object {
 	struct i915_global base;
@@ -41,6 +42,64 @@ void i915_gem_object_free(struct drm_i915_gem_object *obj)
 	return kmem_cache_free(global.slab_objects, obj);
 }
 
+/* some bookkeeping */
+static void i915_gem_info_add_obj(struct drm_i915_private *i915,
+				  u64 size)
+{
+	spin_lock(&i915->mm.object_stat_lock);
+	i915->mm.object_count++;
+	i915->mm.object_memory += size;
+	spin_unlock(&i915->mm.object_stat_lock);
+}
+
+static void i915_gem_info_remove_obj(struct drm_i915_private *i915,
+				     u64 size)
+{
+	spin_lock(&i915->mm.object_stat_lock);
+	i915->mm.object_count--;
+	i915->mm.object_memory -= size;
+	spin_unlock(&i915->mm.object_stat_lock);
+}
+
+static void
+frontbuffer_retire(struct i915_active_request *active,
+		   struct i915_request *request)
+{
+	struct drm_i915_gem_object *obj =
+		container_of(active, typeof(*obj), frontbuffer_write);
+
+	intel_fb_obj_flush(obj, ORIGIN_CS);
+}
+
+void i915_gem_object_init(struct drm_i915_gem_object *obj,
+			  const struct drm_i915_gem_object_ops *ops)
+{
+	mutex_init(&obj->mm.lock);
+
+	spin_lock_init(&obj->vma.lock);
+	INIT_LIST_HEAD(&obj->vma.list);
+
+	INIT_LIST_HEAD(&obj->lut_list);
+	INIT_LIST_HEAD(&obj->batch_pool_link);
+
+	init_rcu_head(&obj->rcu);
+
+	obj->ops = ops;
+
+	reservation_object_init(&obj->__builtin_resv);
+	obj->resv = &obj->__builtin_resv;
+
+	obj->frontbuffer_ggtt_origin = ORIGIN_GTT;
+	i915_active_request_init(&obj->frontbuffer_write,
+				 NULL, frontbuffer_retire);
+
+	obj->mm.madv = I915_MADV_WILLNEED;
+	INIT_RADIX_TREE(&obj->mm.get_page.radix, GFP_KERNEL | __GFP_NOWARN);
+	mutex_init(&obj->mm.get_page.lock);
+
+	i915_gem_info_add_obj(to_i915(obj->base.dev), obj->base.size);
+}
+
 /**
  * Mark up the object's coherency levels for a given cache_level
  * @obj: #drm_i915_gem_object
@@ -63,6 +122,245 @@ void i915_gem_object_set_cache_coherency(struct drm_i915_gem_object *obj,
 		!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE);
 }
 
+void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *file)
+{
+	struct drm_i915_private *i915 = to_i915(gem->dev);
+	struct drm_i915_gem_object *obj = to_intel_bo(gem);
+	struct drm_i915_file_private *fpriv = file->driver_priv;
+	struct i915_lut_handle *lut, *ln;
+
+	mutex_lock(&i915->drm.struct_mutex);
+
+	list_for_each_entry_safe(lut, ln, &obj->lut_list, obj_link) {
+		struct i915_gem_context *ctx = lut->ctx;
+		struct i915_vma *vma;
+
+		GEM_BUG_ON(ctx->file_priv == ERR_PTR(-EBADF));
+		if (ctx->file_priv != fpriv)
+			continue;
+
+		vma = radix_tree_delete(&ctx->handles_vma, lut->handle);
+		GEM_BUG_ON(vma->obj != obj);
+
+		/* We allow the process to have multiple handles to the same
+		 * vma, in the same fd namespace, by virtue of flink/open.
+		 */
+		GEM_BUG_ON(!vma->open_count);
+		if (!--vma->open_count && !i915_vma_is_ggtt(vma))
+			i915_vma_close(vma);
+
+		list_del(&lut->obj_link);
+		list_del(&lut->ctx_link);
+
+		i915_lut_handle_free(lut);
+		__i915_gem_object_release_unless_active(obj);
+	}
+
+	mutex_unlock(&i915->drm.struct_mutex);
+}
+
+static bool discard_backing_storage(struct drm_i915_gem_object *obj)
+{
+	/* If we are the last user of the backing storage (be it shmemfs
+	 * pages or stolen etc), we know that the pages are going to be
+	 * immediately released. In this case, we can then skip copying
+	 * back the contents from the GPU.
+	 */
+
+	if (obj->mm.madv != I915_MADV_WILLNEED)
+		return false;
+
+	if (!obj->base.filp)
+		return true;
+
+	/* At first glance, this looks racy, but then again so would be
+	 * userspace racing mmap against close. However, the first external
+	 * reference to the filp can only be obtained through the
+	 * i915_gem_mmap_ioctl() which safeguards us against the user
+	 * acquiring such a reference whilst we are in the middle of
+	 * freeing the object.
+	 */
+	return file_count(obj->base.filp) == 1;
+}
+
+static void __i915_gem_free_objects(struct drm_i915_private *i915,
+				    struct llist_node *freed)
+{
+	struct drm_i915_gem_object *obj, *on;
+	intel_wakeref_t wakeref;
+
+	wakeref = intel_runtime_pm_get(i915);
+	llist_for_each_entry_safe(obj, on, freed, freed) {
+		struct i915_vma *vma, *vn;
+
+		trace_i915_gem_object_destroy(obj);
+
+		mutex_lock(&i915->drm.struct_mutex);
+
+		GEM_BUG_ON(i915_gem_object_is_active(obj));
+		list_for_each_entry_safe(vma, vn, &obj->vma.list, obj_link) {
+			GEM_BUG_ON(i915_vma_is_active(vma));
+			vma->flags &= ~I915_VMA_PIN_MASK;
+			i915_vma_destroy(vma);
+		}
+		GEM_BUG_ON(!list_empty(&obj->vma.list));
+		GEM_BUG_ON(!RB_EMPTY_ROOT(&obj->vma.tree));
+
+		/* This serializes freeing with the shrinker. Since the free
+		 * is delayed, first by RCU then by the workqueue, we want the
+		 * shrinker to be able to free pages of unreferenced objects,
+		 * or else we may oom whilst there are plenty of deferred
+		 * freed objects.
+		 */
+		if (i915_gem_object_has_pages(obj)) {
+			spin_lock(&i915->mm.obj_lock);
+			list_del_init(&obj->mm.link);
+			spin_unlock(&i915->mm.obj_lock);
+		}
+
+		mutex_unlock(&i915->drm.struct_mutex);
+
+		GEM_BUG_ON(obj->bind_count);
+		GEM_BUG_ON(obj->userfault_count);
+		GEM_BUG_ON(atomic_read(&obj->frontbuffer_bits));
+		GEM_BUG_ON(!list_empty(&obj->lut_list));
+
+		if (obj->ops->release)
+			obj->ops->release(obj);
+
+		if (WARN_ON(i915_gem_object_has_pinned_pages(obj)))
+			atomic_set(&obj->mm.pages_pin_count, 0);
+		__i915_gem_object_put_pages(obj, I915_MM_NORMAL);
+		GEM_BUG_ON(i915_gem_object_has_pages(obj));
+
+		if (obj->base.import_attach)
+			drm_prime_gem_destroy(&obj->base, NULL);
+
+		reservation_object_fini(&obj->__builtin_resv);
+		drm_gem_object_release(&obj->base);
+		i915_gem_info_remove_obj(i915, obj->base.size);
+
+		bitmap_free(obj->bit_17);
+		i915_gem_object_free(obj);
+
+		GEM_BUG_ON(!atomic_read(&i915->mm.free_count));
+		atomic_dec(&i915->mm.free_count);
+
+		if (on)
+			cond_resched();
+	}
+	intel_runtime_pm_put(i915, wakeref);
+}
+
+void i915_gem_flush_free_objects(struct drm_i915_private *i915)
+{
+	struct llist_node *freed;
+
+	/* Free the oldest, most stale object to keep the free_list short */
+	freed = NULL;
+	if (!llist_empty(&i915->mm.free_list)) { /* quick test for hotpath */
+		/* Only one consumer of llist_del_first() allowed */
+		spin_lock(&i915->mm.free_lock);
+		freed = llist_del_first(&i915->mm.free_list);
+		spin_unlock(&i915->mm.free_lock);
+	}
+	if (unlikely(freed)) {
+		freed->next = NULL;
+		__i915_gem_free_objects(i915, freed);
+	}
+}
+
+static void __i915_gem_free_work(struct work_struct *work)
+{
+	struct drm_i915_private *i915 =
+		container_of(work, struct drm_i915_private, mm.free_work);
+	struct llist_node *freed;
+
+	/*
+	 * All file-owned VMA should have been released by this point through
+	 * i915_gem_close_object(), or earlier by i915_gem_context_close().
+	 * However, the object may also be bound into the global GTT (e.g.
+	 * older GPUs without per-process support, or for direct access through
+	 * the GTT either for the user or for scanout). Those VMA still need to
+	 * unbound now.
+	 */
+
+	spin_lock(&i915->mm.free_lock);
+	while ((freed = llist_del_all(&i915->mm.free_list))) {
+		spin_unlock(&i915->mm.free_lock);
+
+		__i915_gem_free_objects(i915, freed);
+		if (need_resched())
+			return;
+
+		spin_lock(&i915->mm.free_lock);
+	}
+	spin_unlock(&i915->mm.free_lock);
+}
+
+static void __i915_gem_free_object_rcu(struct rcu_head *head)
+{
+	struct drm_i915_gem_object *obj =
+		container_of(head, typeof(*obj), rcu);
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
+
+	/*
+	 * We reuse obj->rcu for the freed list, so we had better not treat
+	 * it like a rcu_head from this point forwards. And we expect all
+	 * objects to be freed via this path.
+	 */
+	destroy_rcu_head(&obj->rcu);
+
+	/*
+	 * Since we require blocking on struct_mutex to unbind the freed
+	 * object from the GPU before releasing resources back to the
+	 * system, we can not do that directly from the RCU callback (which may
+	 * be a softirq context), but must instead then defer that work onto a
+	 * kthread. We use the RCU callback rather than move the freed object
+	 * directly onto the work queue so that we can mix between using the
+	 * worker and performing frees directly from subsequent allocations for
+	 * crude but effective memory throttling.
+	 */
+	if (llist_add(&obj->freed, &i915->mm.free_list))
+		queue_work(i915->wq, &i915->mm.free_work);
+}
+
+void i915_gem_free_object(struct drm_gem_object *gem_obj)
+{
+	struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);
+
+	if (obj->mm.quirked)
+		__i915_gem_object_unpin_pages(obj);
+
+	if (discard_backing_storage(obj))
+		obj->mm.madv = I915_MADV_DONTNEED;
+
+	/*
+	 * Before we free the object, make sure any pure RCU-only
+	 * read-side critical sections are complete, e.g.
+	 * i915_gem_busy_ioctl(). For the corresponding synchronized
+	 * lookup see i915_gem_object_lookup_rcu().
+	 */
+	atomic_inc(&to_i915(obj->base.dev)->mm.free_count);
+	call_rcu(&obj->rcu, __i915_gem_free_object_rcu);
+}
+
+void __i915_gem_object_release_unless_active(struct drm_i915_gem_object *obj)
+{
+	lockdep_assert_held(&obj->base.dev->struct_mutex);
+
+	if (!i915_gem_object_has_active_reference(obj) &&
+	    i915_gem_object_is_active(obj))
+		i915_gem_object_set_active_reference(obj);
+	else
+		i915_gem_object_put(obj);
+}
+
+void i915_gem_init__objects(struct drm_i915_private *i915)
+{
+	INIT_WORK(&i915->mm.free_work, __i915_gem_free_work);
+}
+
 static void i915_global_objects_shrink(void)
 {
 	kmem_cache_shrink(global.slab_objects);

drivers/gpu/drm/i915/gem/i915_gem_object.h

@@ -15,9 +15,29 @@
 
 #include "i915_gem_object_types.h"
 
+void i915_gem_init__objects(struct drm_i915_private *i915);
+
 struct drm_i915_gem_object *i915_gem_object_alloc(void);
 void i915_gem_object_free(struct drm_i915_gem_object *obj);
 
+void i915_gem_object_init(struct drm_i915_gem_object *obj,
+			  const struct drm_i915_gem_object_ops *ops);
+struct drm_i915_gem_object *
+i915_gem_object_create_shmem(struct drm_i915_private *i915, u64 size);
+struct drm_i915_gem_object *
+i915_gem_object_create_shmem_from_data(struct drm_i915_private *i915,
+				       const void *data, size_t size);
+
+extern const struct drm_i915_gem_object_ops i915_gem_shmem_ops;
+void __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj,
+				     struct sg_table *pages,
+				     bool needs_clflush);
+
+void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *file);
+void i915_gem_free_object(struct drm_gem_object *obj);
+
+void i915_gem_flush_free_objects(struct drm_i915_private *i915);
+
 /**
  * i915_gem_object_lookup_rcu - look up a temporary GEM object from its handle
  * @filp: DRM file private date
@@ -343,8 +363,23 @@ void i915_gem_object_set_cache_coherency(struct drm_i915_gem_object *obj,
 					 unsigned int cache_level);
 void i915_gem_object_flush_if_display(struct drm_i915_gem_object *obj);
 
-void __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj,
-				     struct sg_table *pages,
-				     bool needs_clflush);
+static inline bool cpu_write_needs_clflush(struct drm_i915_gem_object *obj)
+{
+	if (obj->cache_dirty)
+		return false;
+
+	if (!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE))
+		return true;
+
+	return obj->pin_global; /* currently in use by HW, keep flushed */
+}
+
+static inline void __start_cpu_write(struct drm_i915_gem_object *obj)
+{
+	obj->read_domains = I915_GEM_DOMAIN_CPU;
+	obj->write_domain = I915_GEM_DOMAIN_CPU;
+	if (cpu_write_needs_clflush(obj))
+		obj->cache_dirty = true;
+}
 
 #endif