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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2016 Red Hat
* Author: Rob Clark <robdclark@gmail.com>
*/
#include "msm_drv.h"
#include "msm_gem.h"
#include "msm_gpu.h"
#include "msm_gpu_trace.h"
/* Default disabled for now until it has some more testing on the different
* iommu combinations that can be paired with the driver:
*/
bool enable_eviction = false;
MODULE_PARM_DESC(enable_eviction, "Enable swappable GEM buffers");
module_param(enable_eviction, bool, 0600);
static bool can_swap(void)
{
return enable_eviction && get_nr_swap_pages() > 0;
}
static unsigned long
msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
{
struct msm_drm_private *priv =
container_of(shrinker, struct msm_drm_private, shrinker);
unsigned count = priv->shrinkable_count;
if (can_swap())
count += priv->evictable_count;
return count;
}
static bool
purge(struct msm_gem_object *msm_obj)
{
if (!is_purgeable(msm_obj))
return false;
/*
* This will move the obj out of still_in_list to
* the purged list
*/
msm_gem_purge(&msm_obj->base);
return true;
}
static bool
evict(struct msm_gem_object *msm_obj)
{
if (is_unevictable(msm_obj))
return false;
msm_gem_evict(&msm_obj->base);
return true;
}
static unsigned long
scan(struct msm_drm_private *priv, unsigned nr_to_scan, struct list_head *list,
bool (*shrink)(struct msm_gem_object *msm_obj))
{
unsigned freed = 0;
struct list_head still_in_list;
INIT_LIST_HEAD(&still_in_list);
mutex_lock(&priv->mm_lock);
while (freed < nr_to_scan) {
struct msm_gem_object *msm_obj = list_first_entry_or_null(
list, typeof(*msm_obj), mm_list);
if (!msm_obj)
break;
list_move_tail(&msm_obj->mm_list, &still_in_list);
/*
* If it is in the process of being freed, msm_gem_free_object
* can be blocked on mm_lock waiting to remove it. So just
* skip it.
*/
if (!kref_get_unless_zero(&msm_obj->base.refcount))
continue;
/*
* Now that we own a reference, we can drop mm_lock for the
* rest of the loop body, to reduce contention with the
* retire_submit path (which could make more objects purgeable)
*/
mutex_unlock(&priv->mm_lock);
/*
* Note that this still needs to be trylock, since we can
* hit shrinker in response to trying to get backing pages
* for this obj (ie. while it's lock is already held)
*/
if (!msm_gem_trylock(&msm_obj->base))
goto tail;
if (shrink(msm_obj))
freed += msm_obj->base.size >> PAGE_SHIFT;
msm_gem_unlock(&msm_obj->base);
tail:
drm_gem_object_put(&msm_obj->base);
mutex_lock(&priv->mm_lock);
}
list_splice_tail(&still_in_list, list);
mutex_unlock(&priv->mm_lock);
return freed;
}
static unsigned long
msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
{
struct msm_drm_private *priv =
container_of(shrinker, struct msm_drm_private, shrinker);
unsigned long freed;
freed = scan(priv, sc->nr_to_scan, &priv->inactive_dontneed, purge);
if (freed > 0)
trace_msm_gem_purge(freed << PAGE_SHIFT);
if (can_swap() && freed < sc->nr_to_scan) {
int evicted = scan(priv, sc->nr_to_scan - freed,
&priv->inactive_willneed, evict);
if (evicted > 0)
trace_msm_gem_evict(evicted << PAGE_SHIFT);
freed += evicted;
}
return (freed > 0) ? freed : SHRINK_STOP;
}
/* since we don't know any better, lets bail after a few
* and if necessary the shrinker will be invoked again.
* Seems better than unmapping *everything*
*/
static const int vmap_shrink_limit = 15;
static bool
vmap_shrink(struct msm_gem_object *msm_obj)
{
if (!is_vunmapable(msm_obj))
return false;
msm_gem_vunmap(&msm_obj->base);
return true;
}
static int
msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
{
struct msm_drm_private *priv =
container_of(nb, struct msm_drm_private, vmap_notifier);
struct list_head *mm_lists[] = {
&priv->inactive_dontneed,
&priv->inactive_willneed,
priv->gpu ? &priv->gpu->active_list : NULL,
NULL,
};
unsigned idx, unmapped = 0;
for (idx = 0; mm_lists[idx] && unmapped < vmap_shrink_limit; idx++) {
unmapped += scan(priv, vmap_shrink_limit - unmapped,
mm_lists[idx], vmap_shrink);
}
*(unsigned long *)ptr += unmapped;
if (unmapped > 0)
trace_msm_gem_purge_vmaps(unmapped);
return NOTIFY_DONE;
}
/**
* msm_gem_shrinker_init - Initialize msm shrinker
* @dev: drm device
*
* This function registers and sets up the msm shrinker.
*/
void msm_gem_shrinker_init(struct drm_device *dev)
{
struct msm_drm_private *priv = dev->dev_private;
priv->shrinker.count_objects = msm_gem_shrinker_count;
priv->shrinker.scan_objects = msm_gem_shrinker_scan;
priv->shrinker.seeks = DEFAULT_SEEKS;
WARN_ON(register_shrinker(&priv->shrinker));
priv->vmap_notifier.notifier_call = msm_gem_shrinker_vmap;
WARN_ON(register_vmap_purge_notifier(&priv->vmap_notifier));
}
/**
* msm_gem_shrinker_cleanup - Clean up msm shrinker
* @dev: drm device
*
* This function unregisters the msm shrinker.
*/
void msm_gem_shrinker_cleanup(struct drm_device *dev)
{
struct msm_drm_private *priv = dev->dev_private;
if (priv->shrinker.nr_deferred) {
WARN_ON(unregister_vmap_purge_notifier(&priv->vmap_notifier));
unregister_shrinker(&priv->shrinker);
}
}
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