i915_gem_shrinker.c | Explore in Territory

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright © 2008-2015 Intel Corporation
 */

#include <linux/oom.h>
#include <linux/sched/mm.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 "gt/intel_gt_requests.h"
#include "gt/intel_gt.h"

#include "i915_trace.h"

static bool swap_available(void)
{ … }

static bool can_release_pages(struct drm_i915_gem_object *obj)
{ … }

static bool drop_pages(struct drm_i915_gem_object *obj,
		       unsigned long shrink, bool trylock_vm)
{ … }

static int try_to_writeback(struct drm_i915_gem_object *obj, unsigned int flags)
{ … }

/**
 * i915_gem_shrink - Shrink buffer object caches
 * @ww: i915 gem ww acquire ctx, or NULL
 * @i915: i915 device
 * @target: amount of memory to make available, in pages
 * @nr_scanned: optional output for number of pages scanned (incremental)
 * @shrink: 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 i915_gem_ww_ctx *ww,
		struct drm_i915_private *i915,
		unsigned long target,
		unsigned long *nr_scanned,
		unsigned int shrink)
{ … }

/**
 * i915_gem_shrink_all - Shrink buffer object caches completely
 * @i915: 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 *i915)
{ … }

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 int
i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
{ … }

void i915_gem_driver_register__shrinker(struct drm_i915_private *i915)
{ … }

void i915_gem_driver_unregister__shrinker(struct drm_i915_private *i915)
{ … }

void i915_gem_shrinker_taints_mutex(struct drm_i915_private *i915,
				    struct mutex *mutex)
{ … }

/**
 * i915_gem_object_make_unshrinkable - Hide the object from the shrinker. By
 * default all object types that support shrinking(see IS_SHRINKABLE), will also
 * make the object visible to the shrinker after allocating the system memory
 * pages.
 * @obj: The GEM object.
 *
 * This is typically used for special kernel internal objects that can't be
 * easily processed by the shrinker, like if they are perma-pinned.
 */
void i915_gem_object_make_unshrinkable(struct drm_i915_gem_object *obj)
{ … }

static void ___i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj,
					       struct list_head *head)
{ … }

/**
 * __i915_gem_object_make_shrinkable - Move the object to the tail of the
 * shrinkable list. Objects on this list might be swapped out. Used with
 * WILLNEED objects.
 * @obj: The GEM object.
 *
 * DO NOT USE. This is intended to be called on very special objects that don't
 * yet have mm.pages, but are guaranteed to have potentially reclaimable pages
 * underneath.
 */
void __i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj)
{ … }

/**
 * __i915_gem_object_make_purgeable - Move the object to the tail of the
 * purgeable list. Objects on this list might be swapped out. Used with
 * DONTNEED objects.
 * @obj: The GEM object.
 *
 * DO NOT USE. This is intended to be called on very special objects that don't
 * yet have mm.pages, but are guaranteed to have potentially reclaimable pages
 * underneath.
 */
void __i915_gem_object_make_purgeable(struct drm_i915_gem_object *obj)
{ … }

/**
 * i915_gem_object_make_shrinkable - Move the object to the tail of the
 * shrinkable list. Objects on this list might be swapped out. Used with
 * WILLNEED objects.
 * @obj: The GEM object.
 *
 * MUST only be called on objects which have backing pages.
 *
 * MUST be balanced with previous call to i915_gem_object_make_unshrinkable().
 */
void i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj)
{ … }

/**
 * i915_gem_object_make_purgeable - Move the object to the tail of the purgeable
 * list. Used with DONTNEED objects. Unlike with shrinkable objects, the
 * shrinker will attempt to discard the backing pages, instead of trying to swap
 * them out.
 * @obj: The GEM object.
 *
 * MUST only be called on objects which have backing pages.
 *
 * MUST be balanced with previous call to i915_gem_object_make_unshrinkable().
 */
void i915_gem_object_make_purgeable(struct drm_i915_gem_object *obj)
{ … }
linux/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
