[PATCH v3 05/37] drm/i915/region: support volatile objects

[Matthew Auld <matthew.auld@intel.com>]

Volatile objects are marked as DONTNEED while pinned, therefore once
unpinned the backing store can be discarded.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: CQ Tang <cq.tang@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_internal.c  | 17 +++---
 drivers/gpu/drm/i915/gem/i915_gem_object.h    |  6 ++
 .../gpu/drm/i915/gem/i915_gem_object_types.h  |  3 +-
 drivers/gpu/drm/i915/gem/i915_gem_pages.c     |  6 ++
 drivers/gpu/drm/i915/gem/i915_gem_region.c    |  7 ++-
 .../gpu/drm/i915/gem/selftests/huge_pages.c   | 12 ++--
 drivers/gpu/drm/i915/selftests/i915_gem_gtt.c |  5 +-
 .../drm/i915/selftests/intel_memory_region.c  | 56 +++++++++++++++++++
 8 files changed, 91 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_internal.c b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
index 0c41e04ab8fa..5e72cb1cc2d3 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_internal.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
@@ -117,13 +117,6 @@ static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
 		goto err;
 	}
 
-	/* Mark the pages as dontneed whilst they are still pinned. As soon
-	 * as they are unpinned they are allowed to be reaped by the shrinker,
-	 * and the caller is expected to repopulate - the contents of this
-	 * object are only valid whilst active and pinned.
-	 */
-	obj->mm.madv = I915_MADV_DONTNEED;
-
 	__i915_gem_object_set_pages(obj, st, sg_page_sizes);
 
 	return 0;
@@ -143,7 +136,6 @@ static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj,
 	internal_free_pages(pages);
 
 	obj->mm.dirty = false;
-	obj->mm.madv = I915_MADV_WILLNEED;
 }
 
 static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
@@ -188,6 +180,15 @@ i915_gem_object_create_internal(struct drm_i915_private *i915,
 	drm_gem_private_object_init(&i915->drm, &obj->base, size);
 	i915_gem_object_init(obj, &i915_gem_object_internal_ops);
 
+	/*
+	 * Mark the object as volatile, such that the pages are marked as
+	 * dontneed whilst they are still pinned. As soon as they are unpinned
+	 * they are allowed to be reaped by the shrinker, and the caller is
+	 * expected to repopulate - the contents of this object are only valid
+	 * whilst active and pinned.
+	 */
+	obj->flags = I915_BO_ALLOC_VOLATILE;
+
 	obj->read_domains = I915_GEM_DOMAIN_CPU;
 	obj->write_domain = I915_GEM_DOMAIN_CPU;
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index 3714cf234d64..1af838050d6c 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -122,6 +122,12 @@ i915_gem_object_lock_fence(struct drm_i915_gem_object *obj);
 void i915_gem_object_unlock_fence(struct drm_i915_gem_object *obj,
 				  struct dma_fence *fence);
 
+static inline bool
+i915_gem_object_is_volatile(const struct drm_i915_gem_object *obj)
+{
+	return obj->flags & I915_BO_ALLOC_VOLATILE;
+}
+
 static inline void
 i915_gem_object_set_readonly(struct drm_i915_gem_object *obj)
 {
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
index eb92243d473b..2142d74a57ea 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -118,7 +118,8 @@ struct drm_i915_gem_object {
 
 	unsigned long flags;
 #define I915_BO_ALLOC_CONTIGUOUS BIT(0)
-#define I915_BO_ALLOC_FLAGS (I915_BO_ALLOC_CONTIGUOUS)
+#define I915_BO_ALLOC_VOLATILE   BIT(1)
+#define I915_BO_ALLOC_FLAGS (I915_BO_ALLOC_CONTIGUOUS | I915_BO_ALLOC_VOLATILE)
 
 	/*
 	 * Is the object to be mapped as read-only to the GPU
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index 18f0ce0135c1..d3f0debdb875 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -18,6 +18,9 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
 
 	lockdep_assert_held(&obj->mm.lock);
 
+	if (i915_gem_object_is_volatile(obj))
+		obj->mm.madv = I915_MADV_DONTNEED;
+
 	/* Make the pages coherent with the GPU (flushing any swapin). */
 	if (obj->cache_dirty) {
 		obj->write_domain = 0;
@@ -159,6 +162,9 @@ __i915_gem_object_unset_pages(struct drm_i915_gem_object *obj)
 	if (IS_ERR_OR_NULL(pages))
 		return pages;
 
+	if (i915_gem_object_is_volatile(obj))
+		obj->mm.madv = I915_MADV_WILLNEED;
+
 	i915_gem_object_make_unshrinkable(obj);
 
 	if (obj->mm.mapping) {
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.c b/drivers/gpu/drm/i915/gem/i915_gem_region.c
index d9cd722b5dbf..0d09da9f7168 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_region.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_region.c
@@ -109,7 +109,12 @@ void i915_gem_object_init_memory_region(struct drm_i915_gem_object *obj,
 	obj->flags = flags;
 
 	mutex_lock(&mem->obj_lock);
-	list_add(&obj->mm.region_link, &mem->objects);
+
+	if (obj->flags & I915_BO_ALLOC_VOLATILE)
+		list_add(&obj->mm.region_link, &mem->purgeable);
+	else
+		list_add(&obj->mm.region_link, &mem->objects);
+
 	mutex_unlock(&mem->obj_lock);
 }
 
diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
index 4c594f90b776..6ead53455c51 100644
--- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
@@ -115,8 +115,6 @@ static int get_huge_pages(struct drm_i915_gem_object *obj)
 	if (i915_gem_gtt_prepare_pages(obj, st))
 		goto err;
 
-	obj->mm.madv = I915_MADV_DONTNEED;
-
 	GEM_BUG_ON(sg_page_sizes != obj->mm.page_mask);
 	__i915_gem_object_set_pages(obj, st, sg_page_sizes);
 
@@ -137,7 +135,6 @@ static void put_huge_pages(struct drm_i915_gem_object *obj,
 	huge_pages_free_pages(pages);
 
 	obj->mm.dirty = false;
-	obj->mm.madv = I915_MADV_WILLNEED;
 }
 
 static const struct drm_i915_gem_object_ops huge_page_ops = {
@@ -170,6 +167,8 @@ huge_pages_object(struct drm_i915_private *i915,
 	drm_gem_private_object_init(&i915->drm, &obj->base, size);
 	i915_gem_object_init(obj, &huge_page_ops);
 
+	obj->flags = I915_BO_ALLOC_VOLATILE;
+
 	obj->write_domain = I915_GEM_DOMAIN_CPU;
 	obj->read_domains = I915_GEM_DOMAIN_CPU;
 	obj->cache_level = I915_CACHE_NONE;
@@ -229,8 +228,6 @@ static int fake_get_huge_pages(struct drm_i915_gem_object *obj)
 
 	i915_sg_trim(st);
 
-	obj->mm.madv = I915_MADV_DONTNEED;
-
 	__i915_gem_object_set_pages(obj, st, sg_page_sizes);
 
 	return 0;
@@ -263,8 +260,6 @@ static int fake_get_huge_pages_single(struct drm_i915_gem_object *obj)
 	sg_dma_len(sg) = obj->base.size;
 	sg_dma_address(sg) = page_size;
 
-	obj->mm.madv = I915_MADV_DONTNEED;
-
 	__i915_gem_object_set_pages(obj, st, sg->length);
 
 	return 0;
@@ -283,7 +278,6 @@ static void fake_put_huge_pages(struct drm_i915_gem_object *obj,
 {
 	fake_free_huge_pages(obj, pages);
 	obj->mm.dirty = false;
-	obj->mm.madv = I915_MADV_WILLNEED;
 }
 
 static const struct drm_i915_gem_object_ops fake_ops = {
@@ -323,6 +317,8 @@ fake_huge_pages_object(struct drm_i915_private *i915, u64 size, bool single)
 	else
 		i915_gem_object_init(obj, &fake_ops);
 
+	obj->flags = I915_BO_ALLOC_VOLATILE;
+
 	obj->write_domain = I915_GEM_DOMAIN_CPU;
 	obj->read_domains = I915_GEM_DOMAIN_CPU;
 	obj->cache_level = I915_CACHE_NONE;
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
index 31a51ca1ddcb..81850e3a7d2d 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -88,8 +88,6 @@ static int fake_get_pages(struct drm_i915_gem_object *obj)
 	}
 	GEM_BUG_ON(rem);
 
-	obj->mm.madv = I915_MADV_DONTNEED;
-
 	__i915_gem_object_set_pages(obj, pages, sg_page_sizes);
 
 	return 0;
@@ -101,7 +99,6 @@ static void fake_put_pages(struct drm_i915_gem_object *obj,
 {
 	fake_free_pages(obj, pages);
 	obj->mm.dirty = false;
-	obj->mm.madv = I915_MADV_WILLNEED;
 }
 
 static const struct drm_i915_gem_object_ops fake_ops = {
@@ -128,6 +125,8 @@ fake_dma_object(struct drm_i915_private *i915, u64 size)
 	drm_gem_private_object_init(&i915->drm, &obj->base, size);
 	i915_gem_object_init(obj, &fake_ops);
 
+	obj->flags = I915_BO_ALLOC_VOLATILE;
+
 	obj->write_domain = I915_GEM_DOMAIN_CPU;
 	obj->read_domains = I915_GEM_DOMAIN_CPU;
 	obj->cache_level = I915_CACHE_NONE;
diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
index 70b467d4e811..f94e7eae90e9 100644
--- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
@@ -295,12 +295,68 @@ static int igt_mock_continuous(void *arg)
 	return err;
 }
 
+static int igt_mock_volatile(void *arg)
+{
+	struct intel_memory_region *mem = arg;
+	struct drm_i915_gem_object *obj;
+	int err;
+
+	obj = i915_gem_object_create_region(mem, PAGE_SIZE, 0);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	err = i915_gem_object_pin_pages(obj);
+	if (err)
+		goto err_put;
+
+	i915_gem_object_unpin_pages(obj);
+
+	err = intel_memory_region_evict(mem, PAGE_SIZE, 0);
+	if (err != -ENOSPC) {
+		pr_err("shrink memory region\n");
+		goto err_put;
+	}
+
+	i915_gem_object_put(obj);
+
+	obj = i915_gem_object_create_region(mem, PAGE_SIZE, I915_BO_ALLOC_VOLATILE);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	if (!(obj->flags & I915_BO_ALLOC_VOLATILE)) {
+		pr_err("missing flags\n");
+		goto err_put;
+	}
+
+	err = i915_gem_object_pin_pages(obj);
+	if (err)
+		goto err_put;
+
+	i915_gem_object_unpin_pages(obj);
+
+	err = intel_memory_region_evict(mem, PAGE_SIZE, 0);
+	if (err) {
+		pr_err("failed to shrink memory\n");
+		goto err_put;
+	}
+
+	if (i915_gem_object_has_pages(obj)) {
+		pr_err("object pages not discarded\n");
+		err = -EINVAL;
+	}
+
+err_put:
+	i915_gem_object_put(obj);
+	return err;
+}
+
 int intel_memory_region_mock_selftests(void)
 {
 	static const struct i915_subtest tests[] = {
 		SUBTEST(igt_mock_fill),
 		SUBTEST(igt_mock_shrink),
 		SUBTEST(igt_mock_continuous),
+		SUBTEST(igt_mock_volatile),
 	};
 	struct intel_memory_region *mem;
 	struct drm_i915_private *i915;
-- 
2.20.1

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