drm/i915: Move dev_priv->mm.[un]bound_list to its own lock
Remove the struct_mutex requirement around dev_priv->mm.bound_list and
dev_priv->mm.unbound_list by giving it its own spinlock. This reduces
one more requirement for struct_mutex and in the process gives us
slightly more accurate unbound_list tracking, which should improve the
shrinker - but the drawback is that we drop the retirement before
counting so i915_gem_object_is_active() may be stale and lead us to
underestimate the number of objects that may be shrunk (see commit
bed50aea61df ("drm/i915/shrinker: Flush active on objects before
counting")).
v2: Crosslink the spinlock to the lists it protects, and btw this
changes s/obj->global_link/obj->mm.link/
v3: Fix decoupling of old links in i915_gem_object_attach_phys()
v3.1: Fix the fix, only unlink if it was linked
v3.2: Use a local for to_i915(obj->base.dev)->mm.obj_lock
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171016114037.5556-1-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 1f66a61..60e7fec 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1537,6 +1537,8 @@ static void i915_gem_object_bump_inactive_ggtt(struct drm_i915_gem_object *obj)
struct list_head *list;
struct i915_vma *vma;
+ GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
+
list_for_each_entry(vma, &obj->vma_list, obj_link) {
if (!i915_vma_is_ggtt(vma))
break;
@@ -1551,8 +1553,10 @@ static void i915_gem_object_bump_inactive_ggtt(struct drm_i915_gem_object *obj)
}
i915 = to_i915(obj->base.dev);
+ spin_lock(&i915->mm.obj_lock);
list = obj->bind_count ? &i915->mm.bound_list : &i915->mm.unbound_list;
- list_move_tail(&obj->global_link, list);
+ list_move_tail(&obj->mm.link, list);
+ spin_unlock(&i915->mm.obj_lock);
}
/**
@@ -2253,6 +2257,7 @@ static void __i915_gem_object_reset_page_iter(struct drm_i915_gem_object *obj)
void __i915_gem_object_put_pages(struct drm_i915_gem_object *obj,
enum i915_mm_subclass subclass)
{
+ struct drm_i915_private *i915 = to_i915(obj->base.dev);
struct sg_table *pages;
if (i915_gem_object_has_pinned_pages(obj))
@@ -2273,6 +2278,10 @@ void __i915_gem_object_put_pages(struct drm_i915_gem_object *obj,
pages = fetch_and_zero(&obj->mm.pages);
GEM_BUG_ON(!pages);
+ spin_lock(&i915->mm.obj_lock);
+ list_del(&obj->mm.link);
+ spin_unlock(&i915->mm.obj_lock);
+
if (obj->mm.mapping) {
void *ptr;
@@ -2507,7 +2516,7 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
obj->mm.pages = pages;
if (i915_gem_object_is_tiled(obj) &&
- to_i915(obj->base.dev)->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
+ i915->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
GEM_BUG_ON(obj->mm.quirked);
__i915_gem_object_pin_pages(obj);
obj->mm.quirked = true;
@@ -2529,8 +2538,11 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
if (obj->mm.page_sizes.phys & ~0u << i)
obj->mm.page_sizes.sg |= BIT(i);
}
-
GEM_BUG_ON(!HAS_PAGE_SIZES(i915, obj->mm.page_sizes.sg));
+
+ spin_lock(&i915->mm.obj_lock);
+ list_add(&obj->mm.link, &i915->mm.unbound_list);
+ spin_unlock(&i915->mm.obj_lock);
}
static int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
@@ -4324,7 +4336,6 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
{
mutex_init(&obj->mm.lock);
- INIT_LIST_HEAD(&obj->global_link);
INIT_LIST_HEAD(&obj->vma_list);
INIT_LIST_HEAD(&obj->lut_list);
INIT_LIST_HEAD(&obj->batch_pool_link);
@@ -4496,7 +4507,18 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915,
GEM_BUG_ON(!list_empty(&obj->vma_list));
GEM_BUG_ON(!RB_EMPTY_ROOT(&obj->vma_tree));
- list_del(&obj->global_link);
+ /* 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);
+ }
+
}
intel_runtime_pm_put(i915);
mutex_unlock(&i915->drm.struct_mutex);
@@ -5035,11 +5057,14 @@ i915_gem_load_init(struct drm_i915_private *dev_priv)
goto err_priorities;
INIT_WORK(&dev_priv->mm.free_work, __i915_gem_free_work);
+
+ spin_lock_init(&dev_priv->mm.obj_lock);
init_llist_head(&dev_priv->mm.free_list);
INIT_LIST_HEAD(&dev_priv->mm.unbound_list);
INIT_LIST_HEAD(&dev_priv->mm.bound_list);
INIT_LIST_HEAD(&dev_priv->mm.fence_list);
INIT_LIST_HEAD(&dev_priv->mm.userfault_list);
+
INIT_DELAYED_WORK(&dev_priv->gt.retire_work,
i915_gem_retire_work_handler);
INIT_DELAYED_WORK(&dev_priv->gt.idle_work,
@@ -5133,12 +5158,12 @@ int i915_gem_freeze_late(struct drm_i915_private *dev_priv)
i915_gem_shrink(dev_priv, -1UL, NULL, I915_SHRINK_UNBOUND);
i915_gem_drain_freed_objects(dev_priv);
- mutex_lock(&dev_priv->drm.struct_mutex);
+ spin_lock(&dev_priv->mm.obj_lock);
for (p = phases; *p; p++) {
- list_for_each_entry(obj, *p, global_link)
+ list_for_each_entry(obj, *p, mm.link)
__start_cpu_write(obj);
}
- mutex_unlock(&dev_priv->drm.struct_mutex);
+ spin_unlock(&dev_priv->mm.obj_lock);
return 0;
}
@@ -5457,7 +5482,17 @@ int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align)
goto err_unlock;
}
- pages = obj->mm.pages;
+ pages = fetch_and_zero(&obj->mm.pages);
+ if (pages) {
+ struct drm_i915_private *i915 = to_i915(obj->base.dev);
+
+ __i915_gem_object_reset_page_iter(obj);
+
+ spin_lock(&i915->mm.obj_lock);
+ list_del(&obj->mm.link);
+ spin_unlock(&i915->mm.obj_lock);
+ }
+
obj->ops = &i915_gem_phys_ops;
err = ____i915_gem_object_get_pages(obj);