529 lines
16 KiB
C
529 lines
16 KiB
C
/*
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* Copyright © 2008-2015 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#include <linux/oom.h>
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#include <linux/shmem_fs.h>
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#include <linux/slab.h>
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#include <linux/swap.h>
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#include <linux/pci.h>
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#include <linux/dma-buf.h>
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#include <linux/vmalloc.h>
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#include <drm/drmP.h>
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#include <drm/i915_drm.h>
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#include "i915_drv.h"
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#include "i915_trace.h"
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static bool shrinker_lock(struct drm_i915_private *i915, bool *unlock)
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{
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switch (mutex_trylock_recursive(&i915->drm.struct_mutex)) {
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case MUTEX_TRYLOCK_RECURSIVE:
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*unlock = false;
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return true;
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case MUTEX_TRYLOCK_FAILED:
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*unlock = false;
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preempt_disable();
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do {
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cpu_relax();
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if (mutex_trylock(&i915->drm.struct_mutex)) {
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*unlock = true;
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break;
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}
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} while (!need_resched());
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preempt_enable();
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return *unlock;
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case MUTEX_TRYLOCK_SUCCESS:
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*unlock = true;
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return true;
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}
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BUG();
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}
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static void shrinker_unlock(struct drm_i915_private *i915, bool unlock)
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{
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if (!unlock)
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return;
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mutex_unlock(&i915->drm.struct_mutex);
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}
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static bool swap_available(void)
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{
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return get_nr_swap_pages() > 0;
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}
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static bool can_release_pages(struct drm_i915_gem_object *obj)
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{
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/* Consider only shrinkable ojects. */
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if (!i915_gem_object_is_shrinkable(obj))
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return false;
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/* Only report true if by unbinding the object and putting its pages
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* we can actually make forward progress towards freeing physical
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* pages.
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*
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* If the pages are pinned for any other reason than being bound
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* to the GPU, simply unbinding from the GPU is not going to succeed
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* in releasing our pin count on the pages themselves.
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*/
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if (atomic_read(&obj->mm.pages_pin_count) > obj->bind_count)
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return false;
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/* If any vma are "permanently" pinned, it will prevent us from
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* reclaiming the obj->mm.pages. We only allow scanout objects to claim
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* a permanent pin, along with a few others like the context objects.
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* To simplify the scan, and to avoid walking the list of vma under the
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* object, we just check the count of its permanently pinned.
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*/
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if (READ_ONCE(obj->pin_global))
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return false;
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/* We can only return physical pages to the system if we can either
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* discard the contents (because the user has marked them as being
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* purgeable) or if we can move their contents out to swap.
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*/
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return swap_available() || obj->mm.madv == I915_MADV_DONTNEED;
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}
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static bool unsafe_drop_pages(struct drm_i915_gem_object *obj)
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{
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if (i915_gem_object_unbind(obj) == 0)
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__i915_gem_object_put_pages(obj, I915_MM_SHRINKER);
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return !i915_gem_object_has_pages(obj);
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}
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/**
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* i915_gem_shrink - Shrink buffer object caches
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* @i915: i915 device
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* @target: amount of memory to make available, in pages
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* @nr_scanned: optional output for number of pages scanned (incremental)
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* @flags: control flags for selecting cache types
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*
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* This function is the main interface to the shrinker. It will try to release
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* up to @target pages of main memory backing storage from buffer objects.
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* Selection of the specific caches can be done with @flags. This is e.g. useful
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* when purgeable objects should be removed from caches preferentially.
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*
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* Note that it's not guaranteed that released amount is actually available as
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* free system memory - the pages might still be in-used to due to other reasons
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* (like cpu mmaps) or the mm core has reused them before we could grab them.
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* Therefore code that needs to explicitly shrink buffer objects caches (e.g. to
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* avoid deadlocks in memory reclaim) must fall back to i915_gem_shrink_all().
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*
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* Also note that any kind of pinning (both per-vma address space pins and
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* backing storage pins at the buffer object level) result in the shrinker code
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* having to skip the object.
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*
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* Returns:
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* The number of pages of backing storage actually released.
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*/
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unsigned long
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i915_gem_shrink(struct drm_i915_private *i915,
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unsigned long target,
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unsigned long *nr_scanned,
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unsigned flags)
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{
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const struct {
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struct list_head *list;
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unsigned int bit;
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} phases[] = {
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{ &i915->mm.unbound_list, I915_SHRINK_UNBOUND },
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{ &i915->mm.bound_list, I915_SHRINK_BOUND },
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{ NULL, 0 },
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}, *phase;
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unsigned long count = 0;
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unsigned long scanned = 0;
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bool unlock;
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if (!shrinker_lock(i915, &unlock))
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return 0;
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/*
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* When shrinking the active list, also consider active contexts.
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* Active contexts are pinned until they are retired, and so can
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* not be simply unbound to retire and unpin their pages. To shrink
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* the contexts, we must wait until the gpu is idle.
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*
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* We don't care about errors here; if we cannot wait upon the GPU,
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* we will free as much as we can and hope to get a second chance.
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*/
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if (flags & I915_SHRINK_ACTIVE)
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i915_gem_wait_for_idle(i915, I915_WAIT_LOCKED);
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trace_i915_gem_shrink(i915, target, flags);
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i915_retire_requests(i915);
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/*
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* Unbinding of objects will require HW access; Let us not wake the
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* device just to recover a little memory. If absolutely necessary,
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* we will force the wake during oom-notifier.
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*/
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if ((flags & I915_SHRINK_BOUND) &&
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!intel_runtime_pm_get_if_in_use(i915))
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flags &= ~I915_SHRINK_BOUND;
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/*
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* As we may completely rewrite the (un)bound list whilst unbinding
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* (due to retiring requests) we have to strictly process only
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* one element of the list at the time, and recheck the list
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* on every iteration.
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*
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* In particular, we must hold a reference whilst removing the
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* object as we may end up waiting for and/or retiring the objects.
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* This might release the final reference (held by the active list)
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* and result in the object being freed from under us. This is
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* similar to the precautions the eviction code must take whilst
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* removing objects.
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*
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* Also note that although these lists do not hold a reference to
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* the object we can safely grab one here: The final object
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* unreferencing and the bound_list are both protected by the
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* dev->struct_mutex and so we won't ever be able to observe an
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* object on the bound_list with a reference count equals 0.
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*/
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for (phase = phases; phase->list; phase++) {
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struct list_head still_in_list;
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struct drm_i915_gem_object *obj;
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if ((flags & phase->bit) == 0)
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continue;
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INIT_LIST_HEAD(&still_in_list);
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/*
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* We serialize our access to unreferenced objects through
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* the use of the struct_mutex. While the objects are not
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* yet freed (due to RCU then a workqueue) we still want
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* to be able to shrink their pages, so they remain on
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* the unbound/bound list until actually freed.
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*/
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spin_lock(&i915->mm.obj_lock);
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while (count < target &&
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(obj = list_first_entry_or_null(phase->list,
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typeof(*obj),
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mm.link))) {
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list_move_tail(&obj->mm.link, &still_in_list);
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if (flags & I915_SHRINK_PURGEABLE &&
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obj->mm.madv != I915_MADV_DONTNEED)
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continue;
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if (flags & I915_SHRINK_VMAPS &&
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!is_vmalloc_addr(obj->mm.mapping))
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continue;
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if (!(flags & I915_SHRINK_ACTIVE) &&
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(i915_gem_object_is_active(obj) ||
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i915_gem_object_is_framebuffer(obj)))
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continue;
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if (!can_release_pages(obj))
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continue;
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spin_unlock(&i915->mm.obj_lock);
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if (unsafe_drop_pages(obj)) {
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/* May arrive from get_pages on another bo */
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mutex_lock_nested(&obj->mm.lock,
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I915_MM_SHRINKER);
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if (!i915_gem_object_has_pages(obj)) {
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__i915_gem_object_invalidate(obj);
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count += obj->base.size >> PAGE_SHIFT;
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}
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mutex_unlock(&obj->mm.lock);
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}
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scanned += obj->base.size >> PAGE_SHIFT;
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spin_lock(&i915->mm.obj_lock);
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}
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list_splice_tail(&still_in_list, phase->list);
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spin_unlock(&i915->mm.obj_lock);
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}
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if (flags & I915_SHRINK_BOUND)
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intel_runtime_pm_put(i915);
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i915_retire_requests(i915);
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shrinker_unlock(i915, unlock);
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if (nr_scanned)
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*nr_scanned += scanned;
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return count;
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}
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/**
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* i915_gem_shrink_all - Shrink buffer object caches completely
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* @i915: i915 device
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*
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* This is a simple wraper around i915_gem_shrink() to aggressively shrink all
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* caches completely. It also first waits for and retires all outstanding
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* requests to also be able to release backing storage for active objects.
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*
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* This should only be used in code to intentionally quiescent the gpu or as a
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* last-ditch effort when memory seems to have run out.
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*
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* Returns:
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* The number of pages of backing storage actually released.
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*/
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unsigned long i915_gem_shrink_all(struct drm_i915_private *i915)
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{
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unsigned long freed;
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intel_runtime_pm_get(i915);
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freed = i915_gem_shrink(i915, -1UL, NULL,
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I915_SHRINK_BOUND |
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I915_SHRINK_UNBOUND |
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I915_SHRINK_ACTIVE);
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intel_runtime_pm_put(i915);
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return freed;
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}
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static unsigned long
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i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
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{
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struct drm_i915_private *i915 =
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container_of(shrinker, struct drm_i915_private, mm.shrinker);
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struct drm_i915_gem_object *obj;
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unsigned long num_objects = 0;
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unsigned long count = 0;
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spin_lock(&i915->mm.obj_lock);
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list_for_each_entry(obj, &i915->mm.unbound_list, mm.link)
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if (can_release_pages(obj)) {
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count += obj->base.size >> PAGE_SHIFT;
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num_objects++;
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}
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list_for_each_entry(obj, &i915->mm.bound_list, mm.link)
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if (!i915_gem_object_is_active(obj) && can_release_pages(obj)) {
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count += obj->base.size >> PAGE_SHIFT;
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num_objects++;
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}
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spin_unlock(&i915->mm.obj_lock);
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/* Update our preferred vmscan batch size for the next pass.
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* Our rough guess for an effective batch size is roughly 2
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* available GEM objects worth of pages. That is we don't want
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* the shrinker to fire, until it is worth the cost of freeing an
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* entire GEM object.
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*/
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if (num_objects) {
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unsigned long avg = 2 * count / num_objects;
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i915->mm.shrinker.batch =
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max((i915->mm.shrinker.batch + avg) >> 1,
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128ul /* default SHRINK_BATCH */);
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}
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return count;
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}
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static unsigned long
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i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
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{
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struct drm_i915_private *i915 =
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container_of(shrinker, struct drm_i915_private, mm.shrinker);
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unsigned long freed;
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bool unlock;
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sc->nr_scanned = 0;
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if (!shrinker_lock(i915, &unlock))
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return SHRINK_STOP;
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freed = i915_gem_shrink(i915,
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sc->nr_to_scan,
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&sc->nr_scanned,
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I915_SHRINK_BOUND |
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I915_SHRINK_UNBOUND |
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I915_SHRINK_PURGEABLE);
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if (sc->nr_scanned < sc->nr_to_scan)
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freed += i915_gem_shrink(i915,
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sc->nr_to_scan - sc->nr_scanned,
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&sc->nr_scanned,
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I915_SHRINK_BOUND |
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I915_SHRINK_UNBOUND);
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if (sc->nr_scanned < sc->nr_to_scan && current_is_kswapd()) {
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intel_runtime_pm_get(i915);
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freed += i915_gem_shrink(i915,
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sc->nr_to_scan - sc->nr_scanned,
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&sc->nr_scanned,
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I915_SHRINK_ACTIVE |
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I915_SHRINK_BOUND |
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I915_SHRINK_UNBOUND);
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intel_runtime_pm_put(i915);
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}
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shrinker_unlock(i915, unlock);
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return sc->nr_scanned ? freed : SHRINK_STOP;
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}
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static bool
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shrinker_lock_uninterruptible(struct drm_i915_private *i915, bool *unlock,
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int timeout_ms)
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{
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unsigned long timeout = jiffies + msecs_to_jiffies_timeout(timeout_ms);
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do {
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if (i915_gem_wait_for_idle(i915, 0) == 0 &&
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shrinker_lock(i915, unlock))
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break;
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schedule_timeout_killable(1);
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if (fatal_signal_pending(current))
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return false;
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if (time_after(jiffies, timeout)) {
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pr_err("Unable to lock GPU to purge memory.\n");
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return false;
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}
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} while (1);
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return true;
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}
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static int
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i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
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{
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struct drm_i915_private *i915 =
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container_of(nb, struct drm_i915_private, mm.oom_notifier);
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struct drm_i915_gem_object *obj;
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unsigned long unevictable, bound, unbound, freed_pages;
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freed_pages = i915_gem_shrink_all(i915);
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/* Because we may be allocating inside our own driver, we cannot
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* assert that there are no objects with pinned pages that are not
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* being pointed to by hardware.
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*/
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unbound = bound = unevictable = 0;
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spin_lock(&i915->mm.obj_lock);
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list_for_each_entry(obj, &i915->mm.unbound_list, mm.link) {
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if (!can_release_pages(obj))
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unevictable += obj->base.size >> PAGE_SHIFT;
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else
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unbound += obj->base.size >> PAGE_SHIFT;
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}
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list_for_each_entry(obj, &i915->mm.bound_list, mm.link) {
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if (!can_release_pages(obj))
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unevictable += obj->base.size >> PAGE_SHIFT;
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else
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bound += obj->base.size >> PAGE_SHIFT;
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}
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spin_unlock(&i915->mm.obj_lock);
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if (freed_pages || unbound || bound)
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pr_info("Purging GPU memory, %lu pages freed, "
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"%lu pages still pinned.\n",
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freed_pages, unevictable);
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if (unbound || bound)
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pr_err("%lu and %lu pages still available in the "
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"bound and unbound GPU page lists.\n",
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bound, unbound);
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*(unsigned long *)ptr += freed_pages;
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return NOTIFY_DONE;
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}
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static int
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i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
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{
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struct drm_i915_private *i915 =
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container_of(nb, struct drm_i915_private, mm.vmap_notifier);
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struct i915_vma *vma, *next;
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unsigned long freed_pages = 0;
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bool unlock;
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int ret;
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if (!shrinker_lock_uninterruptible(i915, &unlock, 5000))
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return NOTIFY_DONE;
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/* Force everything onto the inactive lists */
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ret = i915_gem_wait_for_idle(i915, I915_WAIT_LOCKED);
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if (ret)
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goto out;
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intel_runtime_pm_get(i915);
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freed_pages += i915_gem_shrink(i915, -1UL, NULL,
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I915_SHRINK_BOUND |
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I915_SHRINK_UNBOUND |
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I915_SHRINK_ACTIVE |
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I915_SHRINK_VMAPS);
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intel_runtime_pm_put(i915);
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/* We also want to clear any cached iomaps as they wrap vmap */
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list_for_each_entry_safe(vma, next,
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&i915->ggtt.base.inactive_list, vm_link) {
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unsigned long count = vma->node.size >> PAGE_SHIFT;
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if (vma->iomap && i915_vma_unbind(vma) == 0)
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freed_pages += count;
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}
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out:
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shrinker_unlock(i915, unlock);
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*(unsigned long *)ptr += freed_pages;
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return NOTIFY_DONE;
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}
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/**
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* i915_gem_shrinker_register - Register the i915 shrinker
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* @i915: i915 device
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*
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|
* This function registers and sets up the i915 shrinker and OOM handler.
|
|
*/
|
|
void i915_gem_shrinker_register(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;
|
|
WARN_ON(register_shrinker(&i915->mm.shrinker));
|
|
|
|
i915->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
|
|
WARN_ON(register_oom_notifier(&i915->mm.oom_notifier));
|
|
|
|
i915->mm.vmap_notifier.notifier_call = i915_gem_shrinker_vmap;
|
|
WARN_ON(register_vmap_purge_notifier(&i915->mm.vmap_notifier));
|
|
}
|
|
|
|
/**
|
|
* i915_gem_shrinker_unregister - Unregisters the i915 shrinker
|
|
* @i915: i915 device
|
|
*
|
|
* This function unregisters the i915 shrinker and OOM handler.
|
|
*/
|
|
void i915_gem_shrinker_unregister(struct drm_i915_private *i915)
|
|
{
|
|
WARN_ON(unregister_vmap_purge_notifier(&i915->mm.vmap_notifier));
|
|
WARN_ON(unregister_oom_notifier(&i915->mm.oom_notifier));
|
|
unregister_shrinker(&i915->mm.shrinker);
|
|
}
|