--- /dev/null
+/*
+ * 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)) && !defined(CONFIG_PREEMPT_RT_BASE)
+ return mutex->owner == task;
+#else
+ /* Since UP may be pre-empted, we cannot assume that we own the lock */
+ return false;
+#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)
+{
+ 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;
+}
+
+/**
+ * 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);
+ 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;
+}
+
+/**
+ * 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;
+ 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);
+}
Code Review / kvmfornfv.git / blobdiff