/*
* 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 <linux/vmalloc.h>
#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "i915_trace.h"
static bool shrinker_lock(struct drm_i915_private *dev_priv, bool *unlock)
{
switch (mutex_trylock_recursive(&dev_priv->drm.struct_mutex)) {
case MUTEX_TRYLOCK_RECURSIVE:
*unlock = false;
return true;
case MUTEX_TRYLOCK_FAILED:
*unlock = false;
preempt_disable();
do {
cpu_relax();
if (mutex_trylock(&dev_priv->drm.struct_mutex)) {
*unlock = true;
break;
}
} while (!need_resched());
preempt_enable();
return *unlock;
case MUTEX_TRYLOCK_SUCCESS:
*unlock = true;
return true;
}
BUG();
}
static void shrinker_unlock(struct drm_i915_private *dev_priv, bool unlock)
{
if (!unlock)
return;
mutex_unlock(&dev_priv->drm.struct_mutex);
}
static bool any_vma_pinned(struct drm_i915_gem_object *obj)
{
struct i915_vma *vma;
list_for_each_entry(vma, &obj->vma_list, obj_link) {
/* Only GGTT vma may be permanently pinned, and are always
* at the start of the list. We can stop hunting as soon
* as we see a ppGTT vma.
*/
if (!i915_vma_is_ggtt(vma))
break;
if (i915_vma_is_pinned(vma))
return true;
}
return false;
}
static bool swap_available(void)
{
return get_nr_swap_pages() > 0;
}
static bool can_release_pages(struct drm_i915_gem_object *obj)
{
if (!obj->mm.pages)
return false;
/* Consider only shrinkable ojects. */
if (!i915_gem_object_is_shrinkable(obj))
return false;
/* Only report true if by unbinding the object and putting its pages
* we can actually make forward progress towards freeing physical
* pages.
*
* If the pages are pinned for any other reason than being bound
* to the GPU, simply unbinding from the GPU is not going to succeed
* in releasing our pin count on the pages themselves.
*/
if (atomic_read(&obj->mm.pages_pin_count) > obj->bind_count)
return false;
if (any_vma_pinned(obj))
return false;
/* We can only return physical pages to the system if we can either
* discard the contents (because the user has marked them as being
* purgeable) or if we can move their contents out to swap.
*/
return swap_available() || obj->mm.madv == I915_MADV_DONTNEED;
}
static bool unsafe_drop_pages(struct drm_i915_gem_object *obj)
{
if (i915_gem_object_unbind(obj) == 0)
__i915_gem_object_put_pages(obj, I915_MM_SHRINKER);
return !READ_ONCE(obj->mm.pages);
}
/**
* i915_gem_shrink - Shrink buffer object caches
* @dev_priv: i915 device
* @target: amount of memory to make available, in pages
* @nr_scanned: optional output for number of pages scanned (incremental)
* @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,
unsigned long target,
unsigned long *nr_scanned,
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;
unsigned long scanned = 0;
bool unlock;
if (!shrinker_lock(dev_priv, &unlock))
return 0;
trace_i915_gem_shrink(dev_priv, target, flags);
i915_gem_retire_requests(dev_priv);
/*
* Unbinding of objects will require HW access; Let us not wake the
* device just to recover a little memory. If absolutely necessary,
* we will force the wake during oom-notifier.
*/
if ((flags & I915_SHRINK_BOUND) &&
!intel_runtime_pm_get_if_in_use(dev_priv))
flags &= ~I915_SHRINK_BOUND;
/*
* 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;
struct drm_i915_gem_object *obj;
if ((flags & phase->bit) == 0)
continue;
INIT_LIST_HEAD(&still_in_list);
while (count < target &&
(obj = list_first_entry_or_null(phase->list,
typeof(*obj),
global_link))) {
list_move_tail(&obj->global_link, &still_in_list);
if (!obj->mm.pages) {
list_del_init(&obj->global_link);
continue;
}
if (flags & I915_SHRINK_PURGEABLE &&
obj->mm.madv != I915_MADV_DONTNEED)
continue;
if (flags & I915_SHRINK_VMAPS &&
!is_vmalloc_addr(obj->mm.mapping))
continue;
if (!(flags & I915_SHRINK_ACTIVE) &&
(i915_gem_object_is_active(obj) ||
i915_gem_object_is_framebuffer(obj)))
continue;
if (!can_release_pages(obj))
continue;
if (unsafe_drop_pages(obj)) {
/* May arrive from get_pages on another bo */
mutex_lock_nested(&obj->mm.lock,
I915_MM_SHRINKER);
if (!obj->mm.pages) {
__i915_gem_object_invalidate(obj);
list_del_init(&obj->global_link);
count += obj->base.size >> PAGE_SHIFT;
}
mutex_unlock(&obj->mm.lock);
scanned += obj->base.size >> PAGE_SHIFT;
}
}
list_splice_tail(&still_in_list, phase->list);
}
if (flags & I915_SHRINK_BOUND)
intel_runtime_pm_put(dev_priv);
i915_gem_retire_requests(dev_priv);
shrinker_unlock(dev_priv, unlock);
if (nr_scanned)
*nr_scanned += scanned;
return count;
}
/**
* i915_gem_shrink_all - 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)
{
unsigned long freed;
intel_runtime_pm_get(dev_priv);
freed = i915_gem_shrink(dev_priv, -1UL, NULL,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
I915_SHRINK_ACTIVE);
intel_runtime_pm_put(dev_priv);
return freed;
}
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_i915_gem_object *obj;
unsigned long count;
bool unlock;
if (!shrinker_lock(dev_priv, &unlock))
return 0;
i915_gem_retire_requests(dev_priv);
count = 0;
list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_link)
if (can_release_pages(obj))
count += obj->base.size >> PAGE_SHIFT;
list_for_each_entry(obj, &dev_priv->mm.bound_list, global_link) {
if (!i915_gem_object_is_active(obj) && can_release_pages(obj))
count += obj->base.size >> PAGE_SHIFT;
}
shrinker_unlock(dev_priv, unlock);
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);
unsigned long freed;
bool unlock;
sc->nr_scanned = 0;
if (!shrinker_lock(dev_priv, &unlock))
return SHRINK_STOP;
freed = i915_gem_shrink(dev_priv,
sc->nr_to_scan,
&sc->nr_scanned,
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 - sc->nr_scanned,
&sc->nr_scanned,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND);
if (freed < sc->nr_to_scan && current_is_kswapd()) {
intel_runtime_pm_get(dev_priv);
freed += i915_gem_shrink(dev_priv,
sc->nr_to_scan - sc->nr_scanned,
&sc->nr_scanned,
I915_SHRINK_ACTIVE |
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND);
intel_runtime_pm_put(dev_priv);
}
shrinker_unlock(dev_priv, unlock);
return sc->nr_scanned ? freed : SHRINK_STOP;
}
static bool
shrinker_lock_uninterruptible(struct drm_i915_private *dev_priv, bool *unlock,
int timeout_ms)
{
unsigned long timeout = jiffies + msecs_to_jiffies_timeout(timeout_ms);
do {
if (i915_gem_wait_for_idle(dev_priv, 0) == 0 &&
shrinker_lock(dev_priv, unlock))
break;
schedule_timeout_killable(1);
if (fatal_signal_pending(current))
return false;
if (time_after(jiffies, timeout)) {
pr_err("Unable to lock GPU to purge memory.\n");
return false;
}
} while (1);
return true;
}
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_i915_gem_object *obj;
unsigned long unevictable, bound, unbound, freed_pages;
bool unlock;
if (!shrinker_lock_uninterruptible(dev_priv, &unlock, 5000))
return NOTIFY_DONE;
freed_pages = i915_gem_shrink_all(dev_priv);
/* 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 = unevictable = 0;
list_for_each_entry(obj, &dev_priv->mm.unbound_list, global_link) {
if (!obj->mm.pages)
continue;
if (!can_release_pages(obj))
unevictable += obj->base.size >> PAGE_SHIFT;
else
unbound += obj->base.size >> PAGE_SHIFT;
}
list_for_each_entry(obj, &dev_priv->mm.bound_list, global_link) {
if (!obj->mm.pages)
continue;
if (!can_release_pages(obj))
unevictable += obj->base.size >> PAGE_SHIFT;
else
bound += obj->base.size >> PAGE_SHIFT;
}
shrinker_unlock(dev_priv, unlock);
if (freed_pages || unbound || bound)
pr_info("Purging GPU memory, %lu pages freed, "
"%lu pages still pinned.\n",
freed_pages, unevictable);
if (unbound || bound)
pr_err("%lu and %lu pages still available in the "
"bound and unbound GPU page lists.\n",
bound, unbound);
*(unsigned long *)ptr += freed_pages;
return NOTIFY_DONE;
}
static int
i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
{
struct drm_i915_private *dev_priv =
container_of(nb, struct drm_i915_private, mm.vmap_notifier);
struct i915_vma *vma, *next;
unsigned long freed_pages = 0;
bool unlock;
int ret;
if (!shrinker_lock_uninterruptible(dev_priv, &unlock, 5000))
return NOTIFY_DONE;
/* Force everything onto the inactive lists */
ret = i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED);
if (ret)
goto out;
intel_runtime_pm_get(dev_priv);
freed_pages += i915_gem_shrink(dev_priv, -1UL, NULL,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
I915_SHRINK_ACTIVE |
I915_SHRINK_VMAPS);
intel_runtime_pm_put(dev_priv);
/* We also want to clear any cached iomaps as they wrap vmap */
list_for_each_entry_safe(vma, next,
&dev_priv->ggtt.base.inactive_list, vm_link) {
unsigned long count = vma->node.size >> PAGE_SHIFT;
if (vma->iomap && i915_vma_unbind(vma) == 0)
freed_pages += count;
}
out:
shrinker_unlock(dev_priv, unlock);
*(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;
WARN_ON(register_shrinker(&dev_priv->mm.shrinker));
dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
WARN_ON(register_oom_notifier(&dev_priv->mm.oom_notifier));
dev_priv->mm.vmap_notifier.notifier_call = i915_gem_shrinker_vmap;
WARN_ON(register_vmap_purge_notifier(&dev_priv->mm.vmap_notifier));
}
/**
* i915_gem_shrinker_cleanup - Clean up i915 shrinker
* @dev_priv: i915 device
*
* This function unregisters the i915 shrinker and OOM handler.
*/
void i915_gem_shrinker_cleanup(struct drm_i915_private *dev_priv)
{
WARN_ON(unregister_vmap_purge_notifier(&dev_priv->mm.vmap_notifier));
WARN_ON(unregister_oom_notifier(&dev_priv->mm.oom_notifier));
unregister_shrinker(&dev_priv->mm.shrinker);
}
