[PATCH 24/30] drm/i915: Delay publishing objects on the eviction lists

Maarten Lankhorst maarten.lankhorst at linux.intel.com
Fri Sep 11 12:21:43 UTC 2020


From: Thomas Hellström <thomas.hellstrom at intel.com>

When an object is published on an eviction list, it's considered for
eviction and can be locked by other threads. This is strictly not
necessary until the object has pages. To limit eviction lookups that
need to discard the object and facilitate a longer period during
which we can lock the object isolated (trylock or ww lock without
chance of deadlock or interruption), delay eviction list publishing
until pages are set. Also take the object off the eviction lists when
pages are unset. Finally make sure that an object is either locked or
isolated when eviction list manipulation happens.

Signed-off-by: Thomas Hellström <thomas.hellstrom at intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_object.c |  2 ++
 drivers/gpu/drm/i915/gem/i915_gem_pages.c  | 20 +++++++++++++++++++-
 drivers/gpu/drm/i915/gem/i915_gem_region.c | 17 +----------------
 3 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c
index b30653823b1b..eea59566d955 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
@@ -59,6 +59,7 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
 	INIT_LIST_HEAD(&obj->vma.list);
 
 	INIT_LIST_HEAD(&obj->mm.link);
+	INIT_LIST_HEAD(&obj->mm.region_link);
 
 	INIT_LIST_HEAD(&obj->lut_list);
 	spin_lock_init(&obj->lut_lock);
@@ -72,6 +73,7 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
 	GEM_BUG_ON(!(flags & I915_BO_ALLOC_FLAGS));
 	obj->flags = flags;
 
+	obj->mm.region = NULL;
 	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);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index 5eacd14e2c47..d047ce5369d0 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -16,6 +16,8 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
 {
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	unsigned long supported = INTEL_INFO(i915)->page_sizes;
+	struct intel_memory_region *mem;
+	struct list_head *list;
 	int i;
 
 	lockdep_assert_held(&obj->mm.lock);
@@ -62,7 +64,6 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
 	GEM_BUG_ON(!HAS_PAGE_SIZES(i915, obj->mm.page_sizes.sg));
 
 	if (i915_gem_object_is_shrinkable(obj)) {
-		struct list_head *list;
 		unsigned long flags;
 
 		spin_lock_irqsave(&i915->mm.obj_lock, flags);
@@ -79,6 +80,16 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
 		atomic_set(&obj->mm.shrink_pin, 0);
 		spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 	}
+
+	mem = obj->mm.region;
+	if (mem) {
+		mutex_lock(&mem->objects.lock);
+		if (obj->flags & I915_BO_ALLOC_VOLATILE)
+			list_add_tail(&obj->mm.region_link, &mem->objects.purgeable);
+		else
+			list_add_tail(&obj->mm.region_link, &mem->objects.list);
+		mutex_unlock(&mem->objects.lock);
+	}
 }
 
 int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
@@ -169,6 +180,7 @@ static void unmap_object(struct drm_i915_gem_object *obj, void *ptr)
 struct sg_table *
 __i915_gem_object_unset_pages(struct drm_i915_gem_object *obj)
 {
+	struct intel_memory_region *mem = obj->mm.region;
 	struct sg_table *pages;
 
 	pages = fetch_and_zero(&obj->mm.pages);
@@ -180,6 +192,12 @@ __i915_gem_object_unset_pages(struct drm_i915_gem_object *obj)
 
 	i915_gem_object_make_unshrinkable(obj);
 
+	if (mem) {
+		mutex_lock(&mem->objects.lock);
+		list_del_init(&obj->mm.region_link);
+		mutex_unlock(&mem->objects.lock);
+	}
+
 	if (obj->mm.mapping) {
 		unmap_object(obj, page_mask_bits(obj->mm.mapping));
 		obj->mm.mapping = NULL;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.c b/drivers/gpu/drm/i915/gem/i915_gem_region.c
index 6a96741253b3..a7eec681d12d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_region.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_region.c
@@ -109,26 +109,11 @@ void i915_gem_object_init_memory_region(struct drm_i915_gem_object *obj,
 
 	if (obj->base.size <= mem->min_page_size)
 		obj->flags |= I915_BO_ALLOC_CONTIGUOUS;
-
-	mutex_lock(&mem->objects.lock);
-
-	if (obj->flags & I915_BO_ALLOC_VOLATILE)
-		list_add(&obj->mm.region_link, &mem->objects.purgeable);
-	else
-		list_add(&obj->mm.region_link, &mem->objects.list);
-
-	mutex_unlock(&mem->objects.lock);
 }
 
 void i915_gem_object_release_memory_region(struct drm_i915_gem_object *obj)
 {
-	struct intel_memory_region *mem = obj->mm.region;
-
-	mutex_lock(&mem->objects.lock);
-	list_del(&obj->mm.region_link);
-	mutex_unlock(&mem->objects.lock);
-
-	intel_memory_region_put(mem);
+	intel_memory_region_put(obj->mm.region);
 }
 
 struct drm_i915_gem_object *
-- 
2.28.0



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