[PATCH 4/7] drm/i915: Allow page pinning to be in the background
Chris Wilson
chris at chris-wilson.co.uk
Mon Jun 3 20:14:36 UTC 2019
Assume that pages may be pinned in a background task and use a
completion event to synchronise with callers that must access the pages
immediately.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gem/i915_gem_object.c | 1 +
drivers/gpu/drm/i915/gem/i915_gem_object.h | 7 +--
.../gpu/drm/i915/gem/i915_gem_object_types.h | 3 ++
drivers/gpu/drm/i915/gem/i915_gem_pages.c | 53 +++++++++++++++----
4 files changed, 52 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c
index 32c1bad36f58..694a8bbe696b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
@@ -79,6 +79,7 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
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);
+ init_completion(&obj->mm.completion);
}
/**
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index 7cb1871d7128..194e4fb6a259 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -240,7 +240,7 @@ int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj);
int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj);
static inline int __must_check
-i915_gem_object_pin_pages(struct drm_i915_gem_object *obj)
+i915_gem_object_pin_pages_async(struct drm_i915_gem_object *obj)
{
might_lock(&obj->mm.lock);
@@ -250,6 +250,9 @@ i915_gem_object_pin_pages(struct drm_i915_gem_object *obj)
return __i915_gem_object_get_pages(obj);
}
+int __must_check
+i915_gem_object_pin_pages(struct drm_i915_gem_object *obj);
+
static inline bool
i915_gem_object_has_pages(struct drm_i915_gem_object *obj)
{
@@ -273,9 +276,7 @@ i915_gem_object_has_pinned_pages(struct drm_i915_gem_object *obj)
static inline void
__i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj)
{
- GEM_BUG_ON(!i915_gem_object_has_pages(obj));
GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
-
atomic_dec(&obj->mm.pages_pin_count);
}
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 5b05698619ce..d53940922ce8 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -7,6 +7,7 @@
#ifndef __I915_GEM_OBJECT_TYPES_H__
#define __I915_GEM_OBJECT_TYPES_H__
+#include <linux/completion.h>
#include <linux/reservation.h>
#include <drm/drm_gem.h>
@@ -210,6 +211,8 @@ struct drm_i915_gem_object {
*/
struct list_head link;
+ struct completion completion;
+
/**
* Advice: are the backing pages purgeable?
*/
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index 7868dd48d931..68262231f56f 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -72,21 +72,18 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
spin_unlock(&i915->mm.obj_lock);
}
+
+ complete_all(&obj->mm.completion);
}
int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
{
- int err;
-
if (unlikely(obj->mm.madv != I915_MADV_WILLNEED)) {
DRM_DEBUG("Attempting to obtain a purgeable object\n");
return -EFAULT;
}
- err = obj->ops->get_pages(obj);
- GEM_BUG_ON(!err && !i915_gem_object_has_pages(obj));
-
- return err;
+ return obj->ops->get_pages(obj);
}
/* Ensure that the associated pages are gathered from the backing storage
@@ -104,7 +101,7 @@ int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
if (err)
return err;
- if (unlikely(!i915_gem_object_has_pages(obj))) {
+ if (!obj->mm.pages) {
GEM_BUG_ON(i915_gem_object_has_pinned_pages(obj));
err = ____i915_gem_object_get_pages(obj);
@@ -120,6 +117,32 @@ int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
return err;
}
+int i915_gem_object_pin_pages(struct drm_i915_gem_object *obj)
+{
+ int err;
+
+ err = i915_gem_object_pin_pages_async(obj);
+ if (err)
+ return err;
+
+ err = wait_for_completion_interruptible(&obj->mm.completion);
+ if (err)
+ goto err_unpin;
+
+ if (IS_ERR(obj->mm.pages)) {
+ err = PTR_ERR(obj->mm.pages);
+ goto err_unpin;
+ }
+
+ GEM_BUG_ON(!i915_gem_object_has_pages(obj));
+ return 0;
+
+err_unpin:
+ GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
+ atomic_dec(&obj->mm.pages_pin_count);
+ return err;
+}
+
/* Immediately discard the backing storage */
void i915_gem_object_truncate(struct drm_i915_gem_object *obj)
{
@@ -196,6 +219,9 @@ int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj,
GEM_BUG_ON(atomic_read(&obj->bind_count));
+ if (obj->mm.pages == ERR_PTR(-EAGAIN))
+ wait_for_completion(&obj->mm.completion);
+
/* May be called by shrinker from within get_pages() (on another bo) */
mutex_lock_nested(&obj->mm.lock, subclass);
if (unlikely(atomic_read(&obj->mm.pages_pin_count))) {
@@ -222,6 +248,7 @@ int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj,
if (!IS_ERR(pages))
obj->ops->put_pages(obj, pages);
+ reinit_completion(&obj->mm.completion);
err = 0;
unlock:
mutex_unlock(&obj->mm.lock);
@@ -299,7 +326,7 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
type &= ~I915_MAP_OVERRIDE;
if (!atomic_inc_not_zero(&obj->mm.pages_pin_count)) {
- if (unlikely(!i915_gem_object_has_pages(obj))) {
+ if (!obj->mm.pages) {
GEM_BUG_ON(i915_gem_object_has_pinned_pages(obj));
err = ____i915_gem_object_get_pages(obj);
@@ -311,7 +338,6 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
atomic_inc(&obj->mm.pages_pin_count);
pinned = false;
}
- GEM_BUG_ON(!i915_gem_object_has_pages(obj));
ptr = page_unpack_bits(obj->mm.mapping, &has_type);
if (ptr && has_type != type) {
@@ -329,6 +355,15 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
}
if (!ptr) {
+ err = wait_for_completion_interruptible(&obj->mm.completion);
+ if (err)
+ goto err_unpin;
+
+ if (IS_ERR(obj->mm.pages)) {
+ err = PTR_ERR(obj->mm.pages);
+ goto err_unpin;
+ }
+
ptr = i915_gem_object_map(obj, type);
if (!ptr) {
err = -ENOMEM;
--
2.20.1
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