- 根目录:
- drivers
- gpu
- drm
- i915
- i915_gem_shrinker.c
/*
* 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
}
/**
* 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);
}