| /* |
| * 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 "i915_trace.h" |
| |
| static bool swap_available(void) |
| { |
| return get_nr_swap_pages() > 0; |
| } |
| |
| static bool can_release_pages(struct drm_i915_gem_object *obj) |
| { |
| /* Consider only shrinkable ojects. */ |
| if (!i915_gem_object_is_shrinkable(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 drop_pages(struct drm_i915_gem_object *obj, |
| unsigned long shrink, bool trylock_vm) |
| { |
| unsigned long flags; |
| |
| flags = 0; |
| if (shrink & I915_SHRINK_ACTIVE) |
| flags |= I915_GEM_OBJECT_UNBIND_ACTIVE; |
| if (!(shrink & I915_SHRINK_BOUND)) |
| flags |= I915_GEM_OBJECT_UNBIND_TEST; |
| if (trylock_vm) |
| flags |= I915_GEM_OBJECT_UNBIND_VM_TRYLOCK; |
| |
| if (i915_gem_object_unbind(obj, flags) == 0) |
| return true; |
| |
| return false; |
| } |
| |
| static int try_to_writeback(struct drm_i915_gem_object *obj, unsigned int flags) |
| { |
| if (obj->ops->shrink) { |
| unsigned int shrink_flags = 0; |
| |
| if (!(flags & I915_SHRINK_ACTIVE)) |
| shrink_flags |= I915_GEM_OBJECT_SHRINK_NO_GPU_WAIT; |
| |
| if (flags & I915_SHRINK_WRITEBACK) |
| shrink_flags |= I915_GEM_OBJECT_SHRINK_WRITEBACK; |
| |
| return obj->ops->shrink(obj, shrink_flags); |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * 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) |
| { |
| const struct { |
| struct list_head *list; |
| unsigned int bit; |
| } phases[] = { |
| { &i915->mm.purge_list, ~0u }, |
| { |
| &i915->mm.shrink_list, |
| I915_SHRINK_BOUND | I915_SHRINK_UNBOUND |
| }, |
| { NULL, 0 }, |
| }, *phase; |
| intel_wakeref_t wakeref = 0; |
| unsigned long count = 0; |
| unsigned long scanned = 0; |
| int err = 0; |
| |
| /* CHV + VTD workaround use stop_machine(); need to trylock vm->mutex */ |
| bool trylock_vm = !ww && intel_vm_no_concurrent_access_wa(i915); |
| |
| trace_i915_gem_shrink(i915, target, shrink); |
| |
| /* |
| * 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 (shrink & I915_SHRINK_BOUND) { |
| wakeref = intel_runtime_pm_get_if_in_use(&i915->runtime_pm); |
| if (!wakeref) |
| shrink &= ~I915_SHRINK_BOUND; |
| } |
| |
| /* |
| * When shrinking the active list, we should also consider active |
| * contexts. Active contexts are pinned until they are retired, and |
| * so can not be simply unbound to retire and unpin their pages. To |
| * shrink the contexts, we must wait until the gpu is idle and |
| * completed its switch to the kernel context. In short, we do |
| * not have a good mechanism for idling a specific context, but |
| * what we can do is give them a kick so that we do not keep idle |
| * contexts around longer than is necessary. |
| */ |
| if (shrink & I915_SHRINK_ACTIVE) |
| /* Retire requests to unpin all idle contexts */ |
| intel_gt_retire_requests(to_gt(i915)); |
| |
| /* |
| * 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; |
| unsigned long flags; |
| |
| if ((shrink & phase->bit) == 0) |
| continue; |
| |
| INIT_LIST_HEAD(&still_in_list); |
| |
| /* |
| * We serialize our access to unreferenced objects through |
| * the use of the struct_mutex. While the objects are not |
| * yet freed (due to RCU then a workqueue) we still want |
| * to be able to shrink their pages, so they remain on |
| * the unbound/bound list until actually freed. |
| */ |
| spin_lock_irqsave(&i915->mm.obj_lock, flags); |
| while (count < target && |
| (obj = list_first_entry_or_null(phase->list, |
| typeof(*obj), |
| mm.link))) { |
| list_move_tail(&obj->mm.link, &still_in_list); |
| |
| if (shrink & I915_SHRINK_VMAPS && |
| !is_vmalloc_addr(obj->mm.mapping)) |
| continue; |
| |
| if (!(shrink & I915_SHRINK_ACTIVE) && |
| i915_gem_object_is_framebuffer(obj)) |
| continue; |
| |
| if (!can_release_pages(obj)) |
| continue; |
| |
| if (!kref_get_unless_zero(&obj->base.refcount)) |
| continue; |
| |
| spin_unlock_irqrestore(&i915->mm.obj_lock, flags); |
| |
| /* May arrive from get_pages on another bo */ |
| if (!ww) { |
| if (!i915_gem_object_trylock(obj, NULL)) |
| goto skip; |
| } else { |
| err = i915_gem_object_lock(obj, ww); |
| if (err) |
| goto skip; |
| } |
| |
| if (drop_pages(obj, shrink, trylock_vm) && |
| !__i915_gem_object_put_pages(obj) && |
| !try_to_writeback(obj, shrink)) |
| count += obj->base.size >> PAGE_SHIFT; |
| |
| if (!ww) |
| i915_gem_object_unlock(obj); |
| |
| scanned += obj->base.size >> PAGE_SHIFT; |
| skip: |
| i915_gem_object_put(obj); |
| |
| spin_lock_irqsave(&i915->mm.obj_lock, flags); |
| if (err) |
| break; |
| } |
| list_splice_tail(&still_in_list, phase->list); |
| spin_unlock_irqrestore(&i915->mm.obj_lock, flags); |
| if (err) |
| break; |
| } |
| |
| if (shrink & I915_SHRINK_BOUND) |
| intel_runtime_pm_put(&i915->runtime_pm, wakeref); |
| |
| if (err) |
| return err; |
| |
| if (nr_scanned) |
| *nr_scanned += scanned; |
| return count; |
| } |
| |
| /** |
| * 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) |
| { |
| intel_wakeref_t wakeref; |
| unsigned long freed = 0; |
| |
| with_intel_runtime_pm(&i915->runtime_pm, wakeref) { |
| freed = i915_gem_shrink(NULL, i915, -1UL, NULL, |
| I915_SHRINK_BOUND | |
| I915_SHRINK_UNBOUND); |
| } |
| |
| return freed; |
| } |
| |
| static unsigned long |
| i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc) |
| { |
| struct drm_i915_private *i915 = |
| container_of(shrinker, struct drm_i915_private, mm.shrinker); |
| unsigned long num_objects; |
| unsigned long count; |
| |
| count = READ_ONCE(i915->mm.shrink_memory) >> PAGE_SHIFT; |
| num_objects = READ_ONCE(i915->mm.shrink_count); |
| |
| /* |
| * Update our preferred vmscan batch size for the next pass. |
| * Our rough guess for an effective batch size is roughly 2 |
| * available GEM objects worth of pages. That is we don't want |
| * the shrinker to fire, until it is worth the cost of freeing an |
| * entire GEM object. |
| */ |
| if (num_objects) { |
| unsigned long avg = 2 * count / num_objects; |
| |
| i915->mm.shrinker.batch = |
| max((i915->mm.shrinker.batch + avg) >> 1, |
| 128ul /* default SHRINK_BATCH */); |
| } |
| |
| return count; |
| } |
| |
| static unsigned long |
| i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) |
| { |
| struct drm_i915_private *i915 = |
| container_of(shrinker, struct drm_i915_private, mm.shrinker); |
| unsigned long freed; |
| |
| sc->nr_scanned = 0; |
| |
| freed = i915_gem_shrink(NULL, i915, |
| sc->nr_to_scan, |
| &sc->nr_scanned, |
| I915_SHRINK_BOUND | |
| I915_SHRINK_UNBOUND); |
| if (sc->nr_scanned < sc->nr_to_scan && current_is_kswapd()) { |
| intel_wakeref_t wakeref; |
| |
| with_intel_runtime_pm(&i915->runtime_pm, wakeref) { |
| freed += i915_gem_shrink(NULL, i915, |
| sc->nr_to_scan - sc->nr_scanned, |
| &sc->nr_scanned, |
| I915_SHRINK_ACTIVE | |
| I915_SHRINK_BOUND | |
| I915_SHRINK_UNBOUND | |
| I915_SHRINK_WRITEBACK); |
| } |
| } |
| |
| return sc->nr_scanned ? freed : SHRINK_STOP; |
| } |
| |
| static int |
| i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr) |
| { |
| struct drm_i915_private *i915 = |
| container_of(nb, struct drm_i915_private, mm.oom_notifier); |
| struct drm_i915_gem_object *obj; |
| unsigned long unevictable, available, freed_pages; |
| intel_wakeref_t wakeref; |
| unsigned long flags; |
| |
| freed_pages = 0; |
| with_intel_runtime_pm(&i915->runtime_pm, wakeref) |
| freed_pages += i915_gem_shrink(NULL, i915, -1UL, NULL, |
| I915_SHRINK_BOUND | |
| I915_SHRINK_UNBOUND | |
| I915_SHRINK_WRITEBACK); |
| |
| /* 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. |
| */ |
| available = unevictable = 0; |
| spin_lock_irqsave(&i915->mm.obj_lock, flags); |
| list_for_each_entry(obj, &i915->mm.shrink_list, mm.link) { |
| if (!can_release_pages(obj)) |
| unevictable += obj->base.size >> PAGE_SHIFT; |
| else |
| available += obj->base.size >> PAGE_SHIFT; |
| } |
| spin_unlock_irqrestore(&i915->mm.obj_lock, flags); |
| |
| if (freed_pages || available) |
| pr_info("Purging GPU memory, %lu pages freed, " |
| "%lu pages still pinned, %lu pages left available.\n", |
| freed_pages, unevictable, available); |
| |
| *(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 *i915 = |
| container_of(nb, struct drm_i915_private, mm.vmap_notifier); |
| struct i915_vma *vma, *next; |
| unsigned long freed_pages = 0; |
| intel_wakeref_t wakeref; |
| |
| with_intel_runtime_pm(&i915->runtime_pm, wakeref) |
| freed_pages += i915_gem_shrink(NULL, i915, -1UL, NULL, |
| I915_SHRINK_BOUND | |
| I915_SHRINK_UNBOUND | |
| I915_SHRINK_VMAPS); |
| |
| /* We also want to clear any cached iomaps as they wrap vmap */ |
| mutex_lock(&to_gt(i915)->ggtt->vm.mutex); |
| list_for_each_entry_safe(vma, next, |
| &to_gt(i915)->ggtt->vm.bound_list, vm_link) { |
| unsigned long count = i915_vma_size(vma) >> PAGE_SHIFT; |
| struct drm_i915_gem_object *obj = vma->obj; |
| |
| if (!vma->iomap || i915_vma_is_active(vma)) |
| continue; |
| |
| if (!i915_gem_object_trylock(obj, NULL)) |
| continue; |
| |
| if (__i915_vma_unbind(vma) == 0) |
| freed_pages += count; |
| |
| i915_gem_object_unlock(obj); |
| } |
| mutex_unlock(&to_gt(i915)->ggtt->vm.mutex); |
| |
| *(unsigned long *)ptr += freed_pages; |
| return NOTIFY_DONE; |
| } |
| |
| void i915_gem_driver_register__shrinker(struct drm_i915_private *i915) |
| { |
| i915->mm.shrinker.scan_objects = i915_gem_shrinker_scan; |
| i915->mm.shrinker.count_objects = i915_gem_shrinker_count; |
| i915->mm.shrinker.seeks = DEFAULT_SEEKS; |
| i915->mm.shrinker.batch = 4096; |
| drm_WARN_ON(&i915->drm, register_shrinker(&i915->mm.shrinker, |
| "drm-i915_gem")); |
| |
| i915->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom; |
| drm_WARN_ON(&i915->drm, register_oom_notifier(&i915->mm.oom_notifier)); |
| |
| i915->mm.vmap_notifier.notifier_call = i915_gem_shrinker_vmap; |
| drm_WARN_ON(&i915->drm, |
| register_vmap_purge_notifier(&i915->mm.vmap_notifier)); |
| } |
| |
| void i915_gem_driver_unregister__shrinker(struct drm_i915_private *i915) |
| { |
| drm_WARN_ON(&i915->drm, |
| unregister_vmap_purge_notifier(&i915->mm.vmap_notifier)); |
| drm_WARN_ON(&i915->drm, |
| unregister_oom_notifier(&i915->mm.oom_notifier)); |
| unregister_shrinker(&i915->mm.shrinker); |
| } |
| |
| void i915_gem_shrinker_taints_mutex(struct drm_i915_private *i915, |
| struct mutex *mutex) |
| { |
| if (!IS_ENABLED(CONFIG_LOCKDEP)) |
| return; |
| |
| fs_reclaim_acquire(GFP_KERNEL); |
| |
| mutex_acquire(&mutex->dep_map, 0, 0, _RET_IP_); |
| mutex_release(&mutex->dep_map, _RET_IP_); |
| |
| fs_reclaim_release(GFP_KERNEL); |
| } |
| |
| #define obj_to_i915(obj__) to_i915((obj__)->base.dev) |
| |
| /** |
| * 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) |
| { |
| struct drm_i915_private *i915 = obj_to_i915(obj); |
| unsigned long flags; |
| |
| /* |
| * We can only be called while the pages are pinned or when |
| * the pages are released. If pinned, we should only be called |
| * from a single caller under controlled conditions; and on release |
| * only one caller may release us. Neither the two may cross. |
| */ |
| if (atomic_add_unless(&obj->mm.shrink_pin, 1, 0)) |
| return; |
| |
| spin_lock_irqsave(&i915->mm.obj_lock, flags); |
| if (!atomic_fetch_inc(&obj->mm.shrink_pin) && |
| !list_empty(&obj->mm.link)) { |
| list_del_init(&obj->mm.link); |
| i915->mm.shrink_count--; |
| i915->mm.shrink_memory -= obj->base.size; |
| } |
| spin_unlock_irqrestore(&i915->mm.obj_lock, flags); |
| } |
| |
| static void ___i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj, |
| struct list_head *head) |
| { |
| struct drm_i915_private *i915 = obj_to_i915(obj); |
| unsigned long flags; |
| |
| if (!i915_gem_object_is_shrinkable(obj)) |
| return; |
| |
| if (atomic_add_unless(&obj->mm.shrink_pin, -1, 1)) |
| return; |
| |
| spin_lock_irqsave(&i915->mm.obj_lock, flags); |
| GEM_BUG_ON(!kref_read(&obj->base.refcount)); |
| if (atomic_dec_and_test(&obj->mm.shrink_pin)) { |
| GEM_BUG_ON(!list_empty(&obj->mm.link)); |
| |
| list_add_tail(&obj->mm.link, head); |
| i915->mm.shrink_count++; |
| i915->mm.shrink_memory += obj->base.size; |
| |
| } |
| spin_unlock_irqrestore(&i915->mm.obj_lock, flags); |
| } |
| |
| /** |
| * __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_shrinkable(obj, |
| &obj_to_i915(obj)->mm.shrink_list); |
| } |
| |
| /** |
| * __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(obj, |
| &obj_to_i915(obj)->mm.purge_list); |
| } |
| |
| /** |
| * 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) |
| { |
| GEM_BUG_ON(!i915_gem_object_has_pages(obj)); |
| __i915_gem_object_make_shrinkable(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) |
| { |
| GEM_BUG_ON(!i915_gem_object_has_pages(obj)); |
| __i915_gem_object_make_purgeable(obj); |
| } |