[PATCH 1/2] drm/i915: Extract i915_gem_shrinker.c

[PATCH 1/2] drm/i915: Extract i915_gem_shrinker.c

[Daniel Vetter]

Two code changes:
- Extract i915_gem_shrinker_init.
- Inline i915_gem_object_is_purgeable since we open-code it everywhere
  else too.

This already has the benefit of pulling all the shrinker code
together, next patch adds a bit of kerneldoc.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/gpu/drm/i915/Makefile            |   1 +
 drivers/gpu/drm/i915/i915_drv.h          |  17 +-
 drivers/gpu/drm/i915/i915_gem.c          | 274 +----------------------------
 drivers/gpu/drm/i915/i915_gem_shrinker.c | 291 +++++++++++++++++++++++++++++++
 4 files changed, 306 insertions(+), 277 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/i915_gem_shrinker.c

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index d3ebaf204408..a69002e2257d 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -28,6 +28,7 @@ i915-y += i915_cmd_parser.o \
 	  i915_gem_execbuffer.o \
 	  i915_gem_gtt.o \
 	  i915_gem.o \
+	  i915_gem_shrinker.o \
 	  i915_gem_stolen.o \
 	  i915_gem_tiling.o \
 	  i915_gem_userptr.o \
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 81f60b48def2..adf95d4c1afc 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2601,12 +2601,6 @@ int i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
 int i915_gem_wait_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *file_priv);
 void i915_gem_load(struct drm_device *dev);
-unsigned long i915_gem_shrink(struct drm_i915_private *dev_priv,
-			      long target,
-			      unsigned flags);
-#define I915_SHRINK_PURGEABLE 0x1
-#define I915_SHRINK_UNBOUND 0x2
-#define I915_SHRINK_BOUND 0x4
 void *i915_gem_object_alloc(struct drm_device *dev);
 void i915_gem_object_free(struct drm_i915_gem_object *obj);
 void i915_gem_object_init(struct drm_i915_gem_object *obj,
@@ -2954,6 +2948,17 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 					       u32 gtt_offset,
 					       u32 size);
 
+/* i915_gem_shrinker.c */
+unsigned long i915_gem_shrink(struct drm_i915_private *dev_priv,
+			      long target,
+			      unsigned flags);
+#define I915_SHRINK_PURGEABLE 0x1
+#define I915_SHRINK_UNBOUND 0x2
+#define I915_SHRINK_BOUND 0x4
+unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv);
+void i915_gem_shrinker_init(struct drm_i915_private *dev_priv);
+
+
 /* i915_gem_tiling.c */
 static inline bool i915_gem_object_needs_bit17_swizzle(struct drm_i915_gem_object *obj)
 {
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 70de915cec11..8a8e4d188d2f 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2008 Intel Corporation
+ * Copyright © 2008-2015 Intel Corporation
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -32,7 +32,6 @@
 #include "i915_vgpu.h"
 #include "i915_trace.h"
 #include "intel_drv.h"
-#include <linux/oom.h>
 #include <linux/shmem_fs.h>
 #include <linux/slab.h>
 #include <linux/swap.h>
@@ -53,15 +52,6 @@ static void i915_gem_object_update_fence(struct drm_i915_gem_object *obj,
 					 struct drm_i915_fence_reg *fence,
 					 bool enable);
 
-static unsigned long i915_gem_shrinker_count(struct shrinker *shrinker,
-					     struct shrink_control *sc);
-static unsigned long i915_gem_shrinker_scan(struct shrinker *shrinker,
-					    struct shrink_control *sc);
-static int i915_gem_shrinker_oom(struct notifier_block *nb,
-				 unsigned long event,
-				 void *ptr);
-static unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv);
-
 static bool cpu_cache_is_coherent(struct drm_device *dev,
 				  enum i915_cache_level level)
 {
@@ -1936,12 +1926,6 @@ i915_gem_mmap_gtt_ioctl(struct drm_device *dev, void *data,
 	return i915_gem_mmap_gtt(file, dev, args->handle, &args->offset);
 }
 
-static inline int
-i915_gem_object_is_purgeable(struct drm_i915_gem_object *obj)
-{
-	return obj->madv == I915_MADV_DONTNEED;
-}
-
 /* Immediately discard the backing storage */
 static void
 i915_gem_object_truncate(struct drm_i915_gem_object *obj)
@@ -2047,85 +2031,6 @@ i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
 	return 0;
 }
 
-unsigned long
-i915_gem_shrink(struct drm_i915_private *dev_priv,
-		long target, unsigned flags)
-{
-	const struct {
-		struct list_head *list;
-		unsigned int bit;
-	} phases[] = {
-		{ &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
-		{ &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
-		{ NULL, 0 },
-	}, *phase;
-	unsigned long count = 0;
-
-	/*
-	 * As we may completely rewrite the (un)bound list whilst unbinding
-	 * (due to retiring requests) we have to strictly process only
-	 * one element of the list at the time, and recheck the list
-	 * on every iteration.
-	 *
-	 * In particular, we must hold a reference whilst removing the
-	 * object as we may end up waiting for and/or retiring the objects.
-	 * This might release the final reference (held by the active list)
-	 * and result in the object being freed from under us. This is
-	 * similar to the precautions the eviction code must take whilst
-	 * removing objects.
-	 *
-	 * Also note that although these lists do not hold a reference to
-	 * the object we can safely grab one here: The final object
-	 * unreferencing and the bound_list are both protected by the
-	 * dev->struct_mutex and so we won't ever be able to observe an
-	 * object on the bound_list with a reference count equals 0.
-	 */
-	for (phase = phases; phase->list; phase++) {
-		struct list_head still_in_list;
-
-		if ((flags & phase->bit) == 0)
-			continue;
-
-		INIT_LIST_HEAD(&still_in_list);
-		while (count < target && !list_empty(phase->list)) {
-			struct drm_i915_gem_object *obj;
-			struct i915_vma *vma, *v;
-
-			obj = list_first_entry(phase->list,
-					       typeof(*obj), global_list);
-			list_move_tail(&obj->global_list, &still_in_list);
-
-			if (flags & I915_SHRINK_PURGEABLE &&
-			    !i915_gem_object_is_purgeable(obj))
-				continue;
-
-			drm_gem_object_reference(&obj->base);
-
-			/* For the unbound phase, this should be a no-op! */
-			list_for_each_entry_safe(vma, v,
-						 &obj->vma_list, vma_link)
-				if (i915_vma_unbind(vma))
-					break;
-
-			if (i915_gem_object_put_pages(obj) == 0)
-				count += obj->base.size >> PAGE_SHIFT;
-
-			drm_gem_object_unreference(&obj->base);
-		}
-		list_splice(&still_in_list, phase->list);
-	}
-
-	return count;
-}
-
-static unsigned long
-i915_gem_shrink_all(struct drm_i915_private *dev_priv)
-{
-	i915_gem_evict_everything(dev_priv->dev);
-	return i915_gem_shrink(dev_priv, LONG_MAX,
-			       I915_SHRINK_BOUND | I915_SHRINK_UNBOUND);
-}
-
 static int
 i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
 {
@@ -4424,7 +4329,7 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
 		obj->madv = args->madv;
 
 	/* if the object is no longer attached, discard its backing storage */
-	if (i915_gem_object_is_purgeable(obj) && obj->pages == NULL)
+	if (obj->madv == I915_MADV_DONTNEED && obj->pages == NULL)
 		i915_gem_object_truncate(obj);
 
 	args->retained = obj->madv != __I915_MADV_PURGED;
@@ -5049,13 +4954,7 @@ i915_gem_load(struct drm_device *dev)
 
 	dev_priv->mm.interruptible = true;
 
-	dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan;
-	dev_priv->mm.shrinker.count_objects = i915_gem_shrinker_count;
-	dev_priv->mm.shrinker.seeks = DEFAULT_SEEKS;
-	register_shrinker(&dev_priv->mm.shrinker);
-
-	dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
-	register_oom_notifier(&dev_priv->mm.oom_notifier);
+	i915_gem_shrinker_init(dev_priv);
 
 	i915_gem_batch_pool_init(dev, &dev_priv->mm.batch_pool);
 
@@ -5147,77 +5046,6 @@ void i915_gem_track_fb(struct drm_i915_gem_object *old,
 	}
 }
 
-static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
-{
-	if (!mutex_is_locked(mutex))
-		return false;
-
-#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_MUTEXES)
-	return mutex->owner == task;
-#else
-	/* Since UP may be pre-empted, we cannot assume that we own the lock */
-	return false;
-#endif
-}
-
-static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
-{
-	if (!mutex_trylock(&dev->struct_mutex)) {
-		if (!mutex_is_locked_by(&dev->struct_mutex, current))
-			return false;
-
-		if (to_i915(dev)->mm.shrinker_no_lock_stealing)
-			return false;
-
-		*unlock = false;
-	} else
-		*unlock = true;
-
-	return true;
-}
-
-static int num_vma_bound(struct drm_i915_gem_object *obj)
-{
-	struct i915_vma *vma;
-	int count = 0;
-
-	list_for_each_entry(vma, &obj->vma_list, vma_link)
-		if (drm_mm_node_allocated(&vma->node))
-			count++;
-
-	return count;
-}
-
-static unsigned long
-i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
-{
-	struct drm_i915_private *dev_priv =
-		container_of(shrinker, struct drm_i915_private, mm.shrinker);
-	struct drm_device *dev = dev_priv->dev;
-	struct drm_i915_gem_object *obj;
-	unsigned long count;
-	bool unlock;
-
-	if (!i915_gem_shrinker_lock(dev, &unlock))
-		return 0;
-
-	count = 0;
-	list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list)
-		if (obj->pages_pin_count == 0)
-			count += obj->base.size >> PAGE_SHIFT;
-
-	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
-		if (!i915_gem_obj_is_pinned(obj) &&
-		    obj->pages_pin_count == num_vma_bound(obj))
-			count += obj->base.size >> PAGE_SHIFT;
-	}
-
-	if (unlock)
-		mutex_unlock(&dev->struct_mutex);
-
-	return count;
-}
-
 /* All the new VM stuff */
 unsigned long
 i915_gem_obj_offset(struct drm_i915_gem_object *o,
@@ -5318,102 +5146,6 @@ unsigned long i915_gem_obj_size(struct drm_i915_gem_object *o,
 	return 0;
 }
 
-static unsigned long
-i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
-{
-	struct drm_i915_private *dev_priv =
-		container_of(shrinker, struct drm_i915_private, mm.shrinker);
-	struct drm_device *dev = dev_priv->dev;
-	unsigned long freed;
-	bool unlock;
-
-	if (!i915_gem_shrinker_lock(dev, &unlock))
-		return SHRINK_STOP;
-
-	freed = i915_gem_shrink(dev_priv,
-				sc->nr_to_scan,
-				I915_SHRINK_BOUND |
-				I915_SHRINK_UNBOUND |
-				I915_SHRINK_PURGEABLE);
-	if (freed < sc->nr_to_scan)
-		freed += i915_gem_shrink(dev_priv,
-					 sc->nr_to_scan - freed,
-					 I915_SHRINK_BOUND |
-					 I915_SHRINK_UNBOUND);
-	if (unlock)
-		mutex_unlock(&dev->struct_mutex);
-
-	return freed;
-}
-
-static int
-i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
-{
-	struct drm_i915_private *dev_priv =
-		container_of(nb, struct drm_i915_private, mm.oom_notifier);
-	struct drm_device *dev = dev_priv->dev;
-	struct drm_i915_gem_object *obj;
-	unsigned long timeout = msecs_to_jiffies(5000) + 1;
-	unsigned long pinned, bound, unbound, freed_pages;
-	bool was_interruptible;
-	bool unlock;
-
-	while (!i915_gem_shrinker_lock(dev, &unlock) && --timeout) {
-		schedule_timeout_killable(1);
-		if (fatal_signal_pending(current))
-			return NOTIFY_DONE;
-	}
-	if (timeout == 0) {
-		pr_err("Unable to purge GPU memory due lock contention.\n");
-		return NOTIFY_DONE;
-	}
-
-	was_interruptible = dev_priv->mm.interruptible;
-	dev_priv->mm.interruptible = false;
-
-	freed_pages = i915_gem_shrink_all(dev_priv);
-
-	dev_priv->mm.interruptible = was_interruptible;
-
-	/* Because we may be allocating inside our own driver, we cannot
-	 * assert that there are no objects with pinned pages that are not
-	 * being pointed to by hardware.
-	 */
-	unbound = bound = pinned = 0;
-	list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list) {
-		if (!obj->base.filp) /* not backed by a freeable object */
-			continue;
-
-		if (obj->pages_pin_count)
-			pinned += obj->base.size;
-		else
-			unbound += obj->base.size;
-	}
-	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
-		if (!obj->base.filp)
-			continue;
-
-		if (obj->pages_pin_count)
-			pinned += obj->base.size;
-		else
-			bound += obj->base.size;
-	}
-
-	if (unlock)
-		mutex_unlock(&dev->struct_mutex);
-
-	if (freed_pages || unbound || bound)
-		pr_info("Purging GPU memory, %lu bytes freed, %lu bytes still pinned.\n",
-			freed_pages << PAGE_SHIFT, pinned);
-	if (unbound || bound)
-		pr_err("%lu and %lu bytes still available in the "
-		       "bound and unbound GPU page lists.\n",
-		       bound, unbound);
-
-	*(unsigned long *)ptr += freed_pages;
-	return NOTIFY_DONE;
-}
-
 bool i915_gem_obj_is_pinned(struct drm_i915_gem_object *obj)
 {
 	struct i915_vma *vma;
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
new file mode 100644
index 000000000000..9ac78b3d6899
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -0,0 +1,291 @@
+/*
+ * Copyright © 2008-2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include <linux/oom.h>
+#include <linux/shmem_fs.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/pci.h>
+#include <linux/dma-buf.h>
+#include <drm/drmP.h>
+#include <drm/i915_drm.h>
+
+#include "i915_drv.h"
+#include "i915_trace.h"
+
+static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
+{
+	if (!mutex_is_locked(mutex))
+		return false;
+
+#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_MUTEXES)
+	return mutex->owner == task;
+#else
+	/* Since UP may be pre-empted, we cannot assume that we own the lock */
+	return false;
+#endif
+}
+
+unsigned long
+i915_gem_shrink(struct drm_i915_private *dev_priv,
+		long target, unsigned flags)
+{
+	const struct {
+		struct list_head *list;
+		unsigned int bit;
+	} phases[] = {
+		{ &dev_priv->mm.unbound_list, I915_SHRINK_UNBOUND },
+		{ &dev_priv->mm.bound_list, I915_SHRINK_BOUND },
+		{ NULL, 0 },
+	}, *phase;
+	unsigned long count = 0;
+
+	/*
+	 * As we may completely rewrite the (un)bound list whilst unbinding
+	 * (due to retiring requests) we have to strictly process only
+	 * one element of the list at the time, and recheck the list
+	 * on every iteration.
+	 *
+	 * In particular, we must hold a reference whilst removing the
+	 * object as we may end up waiting for and/or retiring the objects.
+	 * This might release the final reference (held by the active list)
+	 * and result in the object being freed from under us. This is
+	 * similar to the precautions the eviction code must take whilst
+	 * removing objects.
+	 *
+	 * Also note that although these lists do not hold a reference to
+	 * the object we can safely grab one here: The final object
+	 * unreferencing and the bound_list are both protected by the
+	 * dev->struct_mutex and so we won't ever be able to observe an
+	 * object on the bound_list with a reference count equals 0.
+	 */
+	for (phase = phases; phase->list; phase++) {
+		struct list_head still_in_list;
+
+		if ((flags & phase->bit) == 0)
+			continue;
+
+		INIT_LIST_HEAD(&still_in_list);
+		while (count < target && !list_empty(phase->list)) {
+			struct drm_i915_gem_object *obj;
+			struct i915_vma *vma, *v;
+
+			obj = list_first_entry(phase->list,
+					       typeof(*obj), global_list);
+			list_move_tail(&obj->global_list, &still_in_list);
+
+			if (flags & I915_SHRINK_PURGEABLE &&
+			    obj->madv != I915_MADV_DONTNEED)
+				continue;
+
+			drm_gem_object_reference(&obj->base);
+
+			/* For the unbound phase, this should be a no-op! */
+			list_for_each_entry_safe(vma, v,
+						 &obj->vma_list, vma_link)
+				if (i915_vma_unbind(vma))
+					break;
+
+			if (i915_gem_object_put_pages(obj) == 0)
+				count += obj->base.size >> PAGE_SHIFT;
+
+			drm_gem_object_unreference(&obj->base);
+		}
+		list_splice(&still_in_list, phase->list);
+	}
+
+	return count;
+}
+
+unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
+{
+	i915_gem_evict_everything(dev_priv->dev);
+	return i915_gem_shrink(dev_priv, LONG_MAX,
+			       I915_SHRINK_BOUND | I915_SHRINK_UNBOUND);
+}
+
+static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
+{
+	if (!mutex_trylock(&dev->struct_mutex)) {
+		if (!mutex_is_locked_by(&dev->struct_mutex, current))
+			return false;
+
+		if (to_i915(dev)->mm.shrinker_no_lock_stealing)
+			return false;
+
+		*unlock = false;
+	} else
+		*unlock = true;
+
+	return true;
+}
+
+static int num_vma_bound(struct drm_i915_gem_object *obj)
+{
+	struct i915_vma *vma;
+	int count = 0;
+
+	list_for_each_entry(vma, &obj->vma_list, vma_link)
+		if (drm_mm_node_allocated(&vma->node))
+			count++;
+
+	return count;
+}
+
+static unsigned long
+i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(shrinker, struct drm_i915_private, mm.shrinker);
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_i915_gem_object *obj;
+	unsigned long count;
+	bool unlock;
+
+	if (!i915_gem_shrinker_lock(dev, &unlock))
+		return 0;
+
+	count = 0;
+	list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list)
+		if (obj->pages_pin_count == 0)
+			count += obj->base.size >> PAGE_SHIFT;
+
+	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
+		if (!i915_gem_obj_is_pinned(obj) &&
+		    obj->pages_pin_count == num_vma_bound(obj))
+			count += obj->base.size >> PAGE_SHIFT;
+	}
+
+	if (unlock)
+		mutex_unlock(&dev->struct_mutex);
+
+	return count;
+}
+
+static unsigned long
+i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(shrinker, struct drm_i915_private, mm.shrinker);
+	struct drm_device *dev = dev_priv->dev;
+	unsigned long freed;
+	bool unlock;
+
+	if (!i915_gem_shrinker_lock(dev, &unlock))
+		return SHRINK_STOP;
+
+	freed = i915_gem_shrink(dev_priv,
+				sc->nr_to_scan,
+				I915_SHRINK_BOUND |
+				I915_SHRINK_UNBOUND |
+				I915_SHRINK_PURGEABLE);
+	if (freed < sc->nr_to_scan)
+		freed += i915_gem_shrink(dev_priv,
+					 sc->nr_to_scan - freed,
+					 I915_SHRINK_BOUND |
+					 I915_SHRINK_UNBOUND);
+	if (unlock)
+		mutex_unlock(&dev->struct_mutex);
+
+	return freed;
+}
+
+static int
+i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(nb, struct drm_i915_private, mm.oom_notifier);
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_i915_gem_object *obj;
+	unsigned long timeout = msecs_to_jiffies(5000) + 1;
+	unsigned long pinned, bound, unbound, freed_pages;
+	bool was_interruptible;
+	bool unlock;
+
+	while (!i915_gem_shrinker_lock(dev, &unlock) && --timeout) {
+		schedule_timeout_killable(1);
+		if (fatal_signal_pending(current))
+			return NOTIFY_DONE;
+	}
+	if (timeout == 0) {
+		pr_err("Unable to purge GPU memory due lock contention.\n");
+		return NOTIFY_DONE;
+	}
+
+	was_interruptible = dev_priv->mm.interruptible;
+	dev_priv->mm.interruptible = false;
+
+	freed_pages = i915_gem_shrink_all(dev_priv);
+
+	dev_priv->mm.interruptible = was_interruptible;
+
+	/* Because we may be allocating inside our own driver, we cannot
+	 * assert that there are no objects with pinned pages that are not
+	 * being pointed to by hardware.
+	 */
+	unbound = bound = pinned = 0;
+	list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_list) {
+		if (!obj->base.filp) /* not backed by a freeable object */
+			continue;
+
+		if (obj->pages_pin_count)
+			pinned += obj->base.size;
+		else
+			unbound += obj->base.size;
+	}
+	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
+		if (!obj->base.filp)
+			continue;
+
+		if (obj->pages_pin_count)
+			pinned += obj->base.size;
+		else
+			bound += obj->base.size;
+	}
+
+	if (unlock)
+		mutex_unlock(&dev->struct_mutex);
+
+	if (freed_pages || unbound || bound)
+		pr_info("Purging GPU memory, %lu bytes freed, %lu bytes still pinned.\n",
+			freed_pages << PAGE_SHIFT, pinned);
+	if (unbound || bound)
+		pr_err("%lu and %lu bytes still available in the "
+		       "bound and unbound GPU page lists.\n",
+		       bound, unbound);
+
+	*(unsigned long *)ptr += freed_pages;
+	return NOTIFY_DONE;
+}
+
+void i915_gem_shrinker_init(struct drm_i915_private *dev_priv)
+{
+	dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan;
+	dev_priv->mm.shrinker.count_objects = i915_gem_shrinker_count;
+	dev_priv->mm.shrinker.seeks = DEFAULT_SEEKS;
+	register_shrinker(&dev_priv->mm.shrinker);
+
+	dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
+	register_oom_notifier(&dev_priv->mm.oom_notifier);
+}
-- 
2.1.4

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[PATCH 2/2] drm/i915: kerneldoc for i915_gem_shrinker.c

[Daniel Vetter]

And remove one bogus * from i915_gem_gtt.c since that's not a
kerneldoc there.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 Documentation/DocBook/drm.tmpl           | 13 +++++++++++-
 drivers/gpu/drm/i915/i915_gem_gtt.c      |  2 +-
 drivers/gpu/drm/i915/i915_gem_shrinker.c | 34 ++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index 7a45775518f6..f4976cd7b32b 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -4184,7 +4184,7 @@ int num_ioctls;</synopsis>
       <sect2>
         <title>Buffer Object Eviction</title>
 	<para>
-	  This section documents the interface function for evicting buffer
+	  This section documents the interface functions for evicting buffer
 	  objects to make space available in the virtual gpu address spaces.
 	  Note that this is mostly orthogonal to shrinking buffer objects
 	  caches, which has the goal to make main memory (shared with the gpu
@@ -4192,6 +4192,17 @@ int num_ioctls;</synopsis>
 	</para>
 !Idrivers/gpu/drm/i915/i915_gem_evict.c
       </sect2>
+      <sect2>
+        <title>Buffer Object Memory Shrinking</title>
+	<para>
+	  This section documents the interface function for shrinking memory
+	  usage of buffer object caches. Shrinking is used to make main memory
+	  available.  Note that this is mostly orthogonal to evicting buffer
+	  objects, which has the goal to make space in gpu virtual address
+	  spaces.
+	</para>
+!Idrivers/gpu/drm/i915/i915_gem_shrinker.c
+      </sect2>
     </sect1>
 
     <sect1>
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index cbf013fd6b98..d8ff1a8e9d43 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -698,7 +698,7 @@ static int gen8_ppgtt_setup_page_tables(struct i915_hw_ppgtt *ppgtt,
 	return 0;
 }
 
-/**
+/*
  * GEN8 legacy ppgtt programming is accomplished through a max 4 PDP registers
  * with a net effect resembling a 2-level page table in normal x86 terms. Each
  * PDP represents 1GB of memory 4 * 512 * 512 * 4096 = 4GB legacy 32b address
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 9ac78b3d6899..86102e5f3a0a 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -47,6 +47,20 @@ static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
 #endif
 }
 
+/**
+ * i915_gem_shrink - Shrink buffer object caches
+ * @dev_priv: i915 device
+ * @target: memory space to make available, in pages
+ * @flags: control flags for selecting cache types
+ *
+ * This function is the main interface to the shrinker. It will try to release
+ * up to @target pages of main memory backing storage from buffer objects.
+ * Selection of the specific caches can be done with @flags. This is e.g. useful
+ * when purgeable objects should be removed from caches preferentially.
+ *
+ * Returns:
+ * The number of pages of backing storage actually released.
+ */
 unsigned long
 i915_gem_shrink(struct drm_i915_private *dev_priv,
 		long target, unsigned flags)
@@ -118,6 +132,20 @@ i915_gem_shrink(struct drm_i915_private *dev_priv,
 	return count;
 }
 
+/**
+ * i915_gem_shrink - Shrink buffer object caches completely
+ * @dev_priv: i915 device
+ *
+ * This is a simple wraper around i915_gem_shrink() to aggressively shrink all
+ * caches completely. It also first waits for and retires all outstanding
+ * requests to also be able to release backing storage for active objects.
+ *
+ * This should only be used in code to intentionally quiescent the gpu or as a
+ * last-ditch effort when memory seems to have run out.
+ *
+ * Returns:
+ * The number of pages of backing storage actually released.
+ */
 unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
 {
 	i915_gem_evict_everything(dev_priv->dev);
@@ -279,6 +307,12 @@ i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
 	return NOTIFY_DONE;
 }
 
+/**
+ * i915_gem_shrinker_init - Initialize i915 shrinker
+ * @dev_priv: i915 device
+ *
+ * This function registers and sets up the i915 shrinker and OOM handler.
+ */
 void i915_gem_shrinker_init(struct drm_i915_private *dev_priv)
 {
 	dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan;
-- 
2.1.4

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Re: [PATCH 2/2] drm/i915: kerneldoc for i915_gem_shrinker.c

[Chris Wilson]

On Wed, Mar 18, 2015 at 10:46:05AM +0100, Daniel Vetter wrote:
> +/**
> + * i915_gem_shrink - Shrink buffer object caches
> + * @dev_priv: i915 device
> + * @target: memory space to make available, in pages

Not memory space, too similar to VM address space.
@target: Amount of memory to make available, in pages

> + * @flags: control flags for selecting cache types
> + *
> + * This function is the main interface to the shrinker. It will try to release
> + * up to @target pages of memory backing storage from buffer objects.

Mention unpinned? Certainly we should try to explain part of the
interaction between pin_pages and pin here. (Though nowadays we have
clarified that slightly by pin explicitly doing a pin_pages.) We should
also mention that not everything we release here will generate freed
pages. (Hmm, though maybe we could change how we count to ensure target
free pages are generated? It still wouldn't help get_pages_gtt as there
is no guarantee that the pages we free will be given back to us...)
-Chris

-- 
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Re: [PATCH 1/2] drm/i915: Extract i915_gem_shrinker.c

[Chris Wilson]

On Wed, Mar 18, 2015 at 10:46:04AM +0100, Daniel Vetter wrote:
> Two code changes:
> - Extract i915_gem_shrinker_init.
> - Inline i915_gem_object_is_purgeable since we open-code it everywhere
>   else too.
> 
> This already has the benefit of pulling all the shrinker code
> together, next patch adds a bit of kerneldoc.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Worth it just for i915_gem_shrinker_init().
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris

-- 
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[PATCH] drm/i915: kerneldoc for i915_gem_shrinker.c

[Daniel Vetter]

And remove one bogus * from i915_gem_gtt.c since that's not a
kerneldoc there.

v2: Review from Chris:
- Clarify memory space to better distinguish from address space.
- Add note that shrink doesn't guarantee the freed memory and that
  users must fall back to shrink_all.
- Explain how pinning ties in with eviction/shrinker.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 Documentation/DocBook/drm.tmpl           | 13 +++++++++-
 drivers/gpu/drm/i915/i915_gem_evict.c    |  4 +++
 drivers/gpu/drm/i915/i915_gem_gtt.c      |  2 +-
 drivers/gpu/drm/i915/i915_gem_shrinker.c | 44 ++++++++++++++++++++++++++++++++
 4 files changed, 61 insertions(+), 2 deletions(-)

diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index 7a45775518f6..f4976cd7b32b 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -4184,7 +4184,7 @@ int num_ioctls;</synopsis>
       <sect2>
         <title>Buffer Object Eviction</title>
 	<para>
-	  This section documents the interface function for evicting buffer
+	  This section documents the interface functions for evicting buffer
 	  objects to make space available in the virtual gpu address spaces.
 	  Note that this is mostly orthogonal to shrinking buffer objects
 	  caches, which has the goal to make main memory (shared with the gpu
@@ -4192,6 +4192,17 @@ int num_ioctls;</synopsis>
 	</para>
 !Idrivers/gpu/drm/i915/i915_gem_evict.c
       </sect2>
+      <sect2>
+        <title>Buffer Object Memory Shrinking</title>
+	<para>
+	  This section documents the interface function for shrinking memory
+	  usage of buffer object caches. Shrinking is used to make main memory
+	  available.  Note that this is mostly orthogonal to evicting buffer
+	  objects, which has the goal to make space in gpu virtual address
+	  spaces.
+	</para>
+!Idrivers/gpu/drm/i915/i915_gem_shrinker.c
+      </sect2>
     </sect1>
 
     <sect1>
diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index e3a49d94da3a..d09e35ed9c9a 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -63,6 +63,10 @@ mark_free(struct i915_vma *vma, struct list_head *unwind)
  *
  * This function is used by the object/vma binding code.
  *
+ * Since this function is only used to free up virtual address space it only
+ * ignores pinned vmas, and not object where the backing storage itself is
+ * pinned. Hence obj->pages_pin_count does not protect against eviction.
+ *
  * To clarify: This is for freeing up virtual address space, not for freeing
  * memory in e.g. the shrinker.
  */
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index cbf013fd6b98..d8ff1a8e9d43 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -698,7 +698,7 @@ static int gen8_ppgtt_setup_page_tables(struct i915_hw_ppgtt *ppgtt,
 	return 0;
 }
 
-/**
+/*
  * GEN8 legacy ppgtt programming is accomplished through a max 4 PDP registers
  * with a net effect resembling a 2-level page table in normal x86 terms. Each
  * PDP represents 1GB of memory 4 * 512 * 512 * 4096 = 4GB legacy 32b address
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 9ac78b3d6899..f7929e769250 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -47,6 +47,30 @@ static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
 #endif
 }
 
+/**
+ * i915_gem_shrink - Shrink buffer object caches
+ * @dev_priv: i915 device
+ * @target: amount of memory to make available, in pages
+ * @flags: control flags for selecting cache types
+ *
+ * This function is the main interface to the shrinker. It will try to release
+ * up to @target pages of main memory backing storage from buffer objects.
+ * Selection of the specific caches can be done with @flags. This is e.g. useful
+ * when purgeable objects should be removed from caches preferentially.
+ *
+ * Note that it's not guaranteed that released amount is actually available as
+ * free system memory - the pages might still be in-used to due to other reasons
+ * (like cpu mmaps) or the mm core has reused them before we could grab them.
+ * Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
+ * avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
+ *
+ * Also note that any kind of pinning (both per-vma address space pins and
+ * backing storage pins at the buffer object level) result in the shrinker code
+ * having to skip the object.
+ *
+ * Returns:
+ * The number of pages of backing storage actually released.
+ */
 unsigned long
 i915_gem_shrink(struct drm_i915_private *dev_priv,
 		long target, unsigned flags)
@@ -118,6 +142,20 @@ i915_gem_shrink(struct drm_i915_private *dev_priv,
 	return count;
 }
 
+/**
+ * i915_gem_shrink - Shrink buffer object caches completely
+ * @dev_priv: i915 device
+ *
+ * This is a simple wraper around i915_gem_shrink() to aggressively shrink all
+ * caches completely. It also first waits for and retires all outstanding
+ * requests to also be able to release backing storage for active objects.
+ *
+ * This should only be used in code to intentionally quiescent the gpu or as a
+ * last-ditch effort when memory seems to have run out.
+ *
+ * Returns:
+ * The number of pages of backing storage actually released.
+ */
 unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
 {
 	i915_gem_evict_everything(dev_priv->dev);
@@ -279,6 +317,12 @@ i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
 	return NOTIFY_DONE;
 }
 
+/**
+ * i915_gem_shrinker_init - Initialize i915 shrinker
+ * @dev_priv: i915 device
+ *
+ * This function registers and sets up the i915 shrinker and OOM handler.
+ */
 void i915_gem_shrinker_init(struct drm_i915_private *dev_priv)
 {
 	dev_priv->mm.shrinker.scan_objects = i915_gem_shrinker_scan;
-- 
2.1.4

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Re: [PATCH] drm/i915: kerneldoc for i915_gem_shrinker.c

[shuang.he]

Tested-By: PRC QA PRTS (Patch Regression Test System Contact: shuang.he@intel.com)
Task id: 5995
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
PNV                 -1              272/272              271/272
ILK                                  301/301              301/301
SNB                                  303/303              303/303
IVB                                  342/342              342/342
BYT                                  287/287              287/287
HSW                                  362/362              362/362
BDW                                  308/308              308/308
-------------------------------------Detailed-------------------------------------
Platform  Test                                drm-intel-nightly          Series Applied
*PNV  igt_gem_userptr_blits_coherency-unsync      PASS(1)      CRASH(1)PASS(1)
Note: You need to pay more attention to line start with '*'
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