[PATCH 17/64] drm/i915: Flatten obj->mm.lock
Maarten Lankhorst
maarten.lankhorst at linux.intel.com
Mon Jan 4 12:50:38 UTC 2021
With userptr fixed, there is no need for all separate lockdep classes
now, and we can remove all lockdep tricks used. A trylock in the
shrinker is all we need now to flatten the locking hierarchy.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_object.c | 6 +---
drivers/gpu/drm/i915/gem/i915_gem_object.h | 20 ++----------
drivers/gpu/drm/i915/gem/i915_gem_pages.c | 34 ++++++++++----------
drivers/gpu/drm/i915/gem/i915_gem_phys.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 10 +++---
drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 2 +-
6 files changed, 27 insertions(+), 47 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c
index 1393988bd5af..028a556ab1a5 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
@@ -62,7 +62,7 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
const struct drm_i915_gem_object_ops *ops,
struct lock_class_key *key, unsigned flags)
{
- __mutex_init(&obj->mm.lock, ops->name ?: "obj->mm.lock", key);
+ mutex_init(&obj->mm.lock);
spin_lock_init(&obj->vma.lock);
INIT_LIST_HEAD(&obj->vma.list);
@@ -86,10 +86,6 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
mutex_init(&obj->mm.get_page.lock);
INIT_RADIX_TREE(&obj->mm.get_dma_page.radix, GFP_KERNEL | __GFP_NOWARN);
mutex_init(&obj->mm.get_dma_page.lock);
-
- if (IS_ENABLED(CONFIG_LOCKDEP) && i915_gem_object_is_shrinkable(obj))
- i915_gem_shrinker_taints_mutex(to_i915(obj->base.dev),
- &obj->mm.lock);
}
/**
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index db4ddbfcee40..aaa574545776 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -322,27 +322,10 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj);
int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj);
-enum i915_mm_subclass { /* lockdep subclass for obj->mm.lock/struct_mutex */
- I915_MM_NORMAL = 0,
- /*
- * Only used by struct_mutex, when called "recursively" from
- * direct-reclaim-esque. Safe because there is only every one
- * struct_mutex in the entire system.
- */
- I915_MM_SHRINKER = 1,
- /*
- * Used for obj->mm.lock when allocating pages. Safe because the object
- * isn't yet on any LRU, and therefore the shrinker can't deadlock on
- * it. As soon as the object has pages, obj->mm.lock nests within
- * fs_reclaim.
- */
- I915_MM_GET_PAGES = 1,
-};
-
static inline int __must_check
i915_gem_object_pin_pages(struct drm_i915_gem_object *obj)
{
- might_lock_nested(&obj->mm.lock, I915_MM_GET_PAGES);
+ might_lock(&obj->mm.lock);
if (atomic_inc_not_zero(&obj->mm.pages_pin_count))
return 0;
@@ -386,6 +369,7 @@ i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj)
}
int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj);
+int __i915_gem_object_put_pages_locked(struct drm_i915_gem_object *obj);
void i915_gem_object_truncate(struct drm_i915_gem_object *obj);
void i915_gem_object_writeback(struct drm_i915_gem_object *obj);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index aefdbe36fe6f..ffc3c3c474b1 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -111,7 +111,7 @@ int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
{
int err;
- err = mutex_lock_interruptible_nested(&obj->mm.lock, I915_MM_GET_PAGES);
+ err = mutex_lock_interruptible(&obj->mm.lock);
if (err)
return err;
@@ -193,21 +193,13 @@ __i915_gem_object_unset_pages(struct drm_i915_gem_object *obj)
return pages;
}
-int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
+int __i915_gem_object_put_pages_locked(struct drm_i915_gem_object *obj)
{
struct sg_table *pages;
- int err;
if (i915_gem_object_has_pinned_pages(obj))
return -EBUSY;
- /* May be called by shrinker from within get_pages() (on another bo) */
- mutex_lock(&obj->mm.lock);
- if (unlikely(atomic_read(&obj->mm.pages_pin_count))) {
- err = -EBUSY;
- goto unlock;
- }
-
i915_gem_object_release_mmap_offset(obj);
/*
@@ -223,14 +215,22 @@ int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
* get_pages backends we should be better able to handle the
* cancellation of the async task in a more uniform manner.
*/
- if (!pages)
- pages = ERR_PTR(-EINVAL);
-
- if (!IS_ERR(pages))
+ if (!IS_ERR_OR_NULL(pages))
obj->ops->put_pages(obj, pages);
- err = 0;
-unlock:
+ return 0;
+}
+
+int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
+{
+ int err;
+
+ if (i915_gem_object_has_pinned_pages(obj))
+ return -EBUSY;
+
+ /* May be called by shrinker from within get_pages() (on another bo) */
+ mutex_lock(&obj->mm.lock);
+ err = __i915_gem_object_put_pages_locked(obj);
mutex_unlock(&obj->mm.lock);
return err;
@@ -338,7 +338,7 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
!i915_gem_object_type_has(obj, I915_GEM_OBJECT_HAS_IOMEM))
return ERR_PTR(-ENXIO);
- err = mutex_lock_interruptible_nested(&obj->mm.lock, I915_MM_GET_PAGES);
+ err = mutex_lock_interruptible(&obj->mm.lock);
if (err)
return ERR_PTR(err);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_phys.c b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
index 144e4940eede..0d176bf06405 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_phys.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
@@ -236,7 +236,7 @@ int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align)
if (err)
return err;
- err = mutex_lock_interruptible_nested(&obj->mm.lock, I915_MM_GET_PAGES);
+ err = mutex_lock_interruptible(&obj->mm.lock);
if (err)
goto err_unlock;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
index c2dba1cd9532..11b8d4e69fc7 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
@@ -49,9 +49,9 @@ static bool unsafe_drop_pages(struct drm_i915_gem_object *obj,
flags = I915_GEM_OBJECT_UNBIND_TEST;
if (i915_gem_object_unbind(obj, flags) == 0)
- __i915_gem_object_put_pages(obj);
+ return true;
- return !i915_gem_object_has_pages(obj);
+ return false;
}
static void try_to_writeback(struct drm_i915_gem_object *obj,
@@ -200,10 +200,10 @@ i915_gem_shrink(struct drm_i915_private *i915,
spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
- if (unsafe_drop_pages(obj, shrink)) {
+ if (unsafe_drop_pages(obj, shrink) &&
+ mutex_trylock(&obj->mm.lock)) {
/* May arrive from get_pages on another bo */
- mutex_lock(&obj->mm.lock);
- if (!i915_gem_object_has_pages(obj)) {
+ if (!__i915_gem_object_put_pages_locked(obj)) {
try_to_writeback(obj, shrink);
count += obj->base.size >> PAGE_SHIFT;
}
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index d07f84328edd..b1c035c55708 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -246,7 +246,7 @@ static int i915_gem_object_userptr_unbind(struct drm_i915_gem_object *obj, bool
if (GEM_WARN_ON(i915_gem_object_has_pinned_pages(obj)))
return -EBUSY;
- mutex_lock_nested(&obj->mm.lock, I915_MM_GET_PAGES);
+ mutex_lock(&obj->mm.lock);
pages = __i915_gem_object_unset_pages(obj);
if (!IS_ERR_OR_NULL(pages))
--
2.30.0.rc1
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