linux/drivers/gpu/drm/i915/i915_gem_evict.c
Chris Wilson 7155b057c6 drm/i915: Retire before attempting to evict from the active lists
Some object retain an extra pin whilst they are active (e.g. contexts).
This excludes them from being considered for eviction unless we idle the
GPU. If before we look at the active list, we retire beforehand we can
hopefully remove a few excess pins and reduce the amount of searching
required.

v2: Similar principle applies to evict_for_vma

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20161209150555.602-1-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
2016-12-12 12:25:32 +00:00

372 lines
11 KiB
C

/*
* Copyright © 2008-2010 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.
*
* Authors:
* Eric Anholt <eric@anholt.net>
* Chris Wilson <chris@chris-wilson.co.uuk>
*
*/
#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "intel_drv.h"
#include "i915_trace.h"
static bool ggtt_is_idle(struct drm_i915_private *dev_priv)
{
struct i915_ggtt *ggtt = &dev_priv->ggtt;
struct intel_engine_cs *engine;
enum intel_engine_id id;
for_each_engine(engine, dev_priv, id) {
struct intel_timeline *tl;
tl = &ggtt->base.timeline.engine[engine->id];
if (i915_gem_active_isset(&tl->last_request))
return false;
}
return true;
}
static bool
mark_free(struct i915_vma *vma, unsigned int flags, struct list_head *unwind)
{
if (i915_vma_is_pinned(vma))
return false;
if (WARN_ON(!list_empty(&vma->exec_list)))
return false;
if (flags & PIN_NONFAULT && !list_empty(&vma->obj->userfault_link))
return false;
list_add(&vma->exec_list, unwind);
return drm_mm_scan_add_block(&vma->node);
}
/**
* i915_gem_evict_something - Evict vmas to make room for binding a new one
* @vm: address space to evict from
* @min_size: size of the desired free space
* @alignment: alignment constraint of the desired free space
* @cache_level: cache_level for the desired space
* @start: start (inclusive) of the range from which to evict objects
* @end: end (exclusive) of the range from which to evict objects
* @flags: additional flags to control the eviction algorithm
*
* This function will try to evict vmas until a free space satisfying the
* requirements is found. Callers must check first whether any such hole exists
* already before calling this function.
*
* This function is used by the object/vma binding code.
*
* Since this function is only used to free up virtual address space it only
* ignores pinned vmas, and not object where the backing storage itself is
* pinned. Hence obj->pages_pin_count does not protect against eviction.
*
* To clarify: This is for freeing up virtual address space, not for freeing
* memory in e.g. the shrinker.
*/
int
i915_gem_evict_something(struct i915_address_space *vm,
u64 min_size, u64 alignment,
unsigned cache_level,
u64 start, u64 end,
unsigned flags)
{
struct drm_i915_private *dev_priv = vm->i915;
struct list_head eviction_list;
struct list_head *phases[] = {
&vm->inactive_list,
&vm->active_list,
NULL,
}, **phase;
struct i915_vma *vma, *next;
int ret;
lockdep_assert_held(&vm->i915->drm.struct_mutex);
trace_i915_gem_evict(vm, min_size, alignment, flags);
/*
* The goal is to evict objects and amalgamate space in LRU order.
* The oldest idle objects reside on the inactive list, which is in
* retirement order. The next objects to retire are those in flight,
* on the active list, again in retirement order.
*
* The retirement sequence is thus:
* 1. Inactive objects (already retired)
* 2. Active objects (will stall on unbinding)
*
* On each list, the oldest objects lie at the HEAD with the freshest
* object on the TAIL.
*/
if (start != 0 || end != vm->total) {
drm_mm_init_scan_with_range(&vm->mm, min_size,
alignment, cache_level,
start, end);
} else
drm_mm_init_scan(&vm->mm, min_size, alignment, cache_level);
/* Retire before we search the active list. Although we have
* reasonable accuracy in our retirement lists, we may have
* a stray pin (preventing eviction) that can only be resolved by
* retiring.
*/
if (!(flags & PIN_NONBLOCK))
i915_gem_retire_requests(dev_priv);
else
phases[1] = NULL;
search_again:
INIT_LIST_HEAD(&eviction_list);
phase = phases;
do {
list_for_each_entry(vma, *phase, vm_link)
if (mark_free(vma, flags, &eviction_list))
goto found;
} while (*++phase);
/* Nothing found, clean up and bail out! */
list_for_each_entry_safe(vma, next, &eviction_list, exec_list) {
ret = drm_mm_scan_remove_block(&vma->node);
BUG_ON(ret);
INIT_LIST_HEAD(&vma->exec_list);
}
/* Can we unpin some objects such as idle hw contents,
* or pending flips? But since only the GGTT has global entries
* such as scanouts, rinbuffers and contexts, we can skip the
* purge when inspecting per-process local address spaces.
*/
if (!i915_is_ggtt(vm) || flags & PIN_NONBLOCK)
return -ENOSPC;
if (ggtt_is_idle(dev_priv)) {
/* If we still have pending pageflip completions, drop
* back to userspace to give our workqueues time to
* acquire our locks and unpin the old scanouts.
*/
return intel_has_pending_fb_unpin(dev_priv) ? -EAGAIN : -ENOSPC;
}
/* Not everything in the GGTT is tracked via vma (otherwise we
* could evict as required with minimal stalling) so we are forced
* to idle the GPU and explicitly retire outstanding requests in
* the hopes that we can then remove contexts and the like only
* bound by their active reference.
*/
ret = i915_gem_switch_to_kernel_context(dev_priv);
if (ret)
return ret;
ret = i915_gem_wait_for_idle(dev_priv,
I915_WAIT_INTERRUPTIBLE |
I915_WAIT_LOCKED);
if (ret)
return ret;
i915_gem_retire_requests(dev_priv);
goto search_again;
found:
/* drm_mm doesn't allow any other other operations while
* scanning, therefore store to-be-evicted objects on a
* temporary list and take a reference for all before
* calling unbind (which may remove the active reference
* of any of our objects, thus corrupting the list).
*/
list_for_each_entry_safe(vma, next, &eviction_list, exec_list) {
if (drm_mm_scan_remove_block(&vma->node))
__i915_vma_pin(vma);
else
list_del_init(&vma->exec_list);
}
/* Unbinding will emit any required flushes */
while (!list_empty(&eviction_list)) {
vma = list_first_entry(&eviction_list,
struct i915_vma,
exec_list);
list_del_init(&vma->exec_list);
__i915_vma_unpin(vma);
if (ret == 0)
ret = i915_vma_unbind(vma);
}
return ret;
}
/**
* i915_gem_evict_for_vma - Evict vmas to make room for binding a new one
* @target: address space and range to evict for
* @flags: additional flags to control the eviction algorithm
*
* This function will try to evict vmas that overlap the target node.
*
* To clarify: This is for freeing up virtual address space, not for freeing
* memory in e.g. the shrinker.
*/
int i915_gem_evict_for_vma(struct i915_vma *target, unsigned int flags)
{
LIST_HEAD(eviction_list);
struct drm_mm_node *node;
u64 start = target->node.start;
u64 end = start + target->node.size;
struct i915_vma *vma, *next;
bool check_color;
int ret = 0;
lockdep_assert_held(&target->vm->i915->drm.struct_mutex);
trace_i915_gem_evict_vma(target, flags);
/* Retire before we search the active list. Although we have
* reasonable accuracy in our retirement lists, we may have
* a stray pin (preventing eviction) that can only be resolved by
* retiring.
*/
if (!(flags & PIN_NONBLOCK))
i915_gem_retire_requests(target->vm->i915);
check_color = target->vm->mm.color_adjust;
if (check_color) {
/* Expand search to cover neighbouring guard pages (or lack!) */
if (start > target->vm->start)
start -= 4096;
if (end < target->vm->start + target->vm->total)
end += 4096;
}
drm_mm_for_each_node_in_range(node, &target->vm->mm, start, end) {
/* If we find any non-objects (!vma), we cannot evict them */
if (node->color == I915_COLOR_UNEVICTABLE) {
ret = -ENOSPC;
break;
}
vma = container_of(node, typeof(*vma), node);
/* If we are using coloring to insert guard pages between
* different cache domains within the address space, we have
* to check whether the objects on either side of our range
* abutt and conflict. If they are in conflict, then we evict
* those as well to make room for our guard pages.
*/
if (check_color) {
if (vma->node.start + vma->node.size == target->node.start) {
if (vma->node.color == target->node.color)
continue;
}
if (vma->node.start == target->node.start + target->node.size) {
if (vma->node.color == target->node.color)
continue;
}
}
if (flags & PIN_NONBLOCK &&
(i915_vma_is_pinned(vma) || i915_vma_is_active(vma))) {
ret = -ENOSPC;
break;
}
/* Overlap of objects in the same batch? */
if (i915_vma_is_pinned(vma)) {
ret = -ENOSPC;
if (vma->exec_entry &&
vma->exec_entry->flags & EXEC_OBJECT_PINNED)
ret = -EINVAL;
break;
}
/* Never show fear in the face of dragons!
*
* We cannot directly remove this node from within this
* iterator and as with i915_gem_evict_something() we employ
* the vma pin_count in order to prevent the action of
* unbinding one vma from freeing (by dropping its active
* reference) another in our eviction list.
*/
__i915_vma_pin(vma);
list_add(&vma->exec_list, &eviction_list);
}
list_for_each_entry_safe(vma, next, &eviction_list, exec_list) {
list_del_init(&vma->exec_list);
__i915_vma_unpin(vma);
if (ret == 0)
ret = i915_vma_unbind(vma);
}
return ret;
}
/**
* i915_gem_evict_vm - Evict all idle vmas from a vm
* @vm: Address space to cleanse
* @do_idle: Boolean directing whether to idle first.
*
* This function evicts all idles vmas from a vm. If all unpinned vmas should be
* evicted the @do_idle needs to be set to true.
*
* This is used by the execbuf code as a last-ditch effort to defragment the
* address space.
*
* To clarify: This is for freeing up virtual address space, not for freeing
* memory in e.g. the shrinker.
*/
int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)
{
struct i915_vma *vma, *next;
int ret;
lockdep_assert_held(&vm->i915->drm.struct_mutex);
trace_i915_gem_evict_vm(vm);
if (do_idle) {
struct drm_i915_private *dev_priv = vm->i915;
if (i915_is_ggtt(vm)) {
ret = i915_gem_switch_to_kernel_context(dev_priv);
if (ret)
return ret;
}
ret = i915_gem_wait_for_idle(dev_priv,
I915_WAIT_INTERRUPTIBLE |
I915_WAIT_LOCKED);
if (ret)
return ret;
i915_gem_retire_requests(dev_priv);
WARN_ON(!list_empty(&vm->active_list));
}
list_for_each_entry_safe(vma, next, &vm->inactive_list, vm_link)
if (!i915_vma_is_pinned(vma))
WARN_ON(i915_vma_unbind(vma));
return 0;
}