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/*
* 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 "gem/i915_gem_context.h"
#include "gt/intel_gt_requests.h"
#include "i915_drv.h"
#include "i915_trace.h"
I915_SELFTEST_DECLARE(static struct igt_evict_ctl {
bool fail_if_busy:1;
} igt_evict_ctl;)
static int ggtt_flush(struct intel_gt *gt)
{
/*
* 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.
*/
return intel_gt_wait_for_idle(gt, MAX_SCHEDULE_TIMEOUT);
}
static bool
mark_free(struct drm_mm_scan *scan,
struct i915_vma *vma,
unsigned int flags,
struct list_head *unwind)
{
if (i915_vma_is_pinned(vma))
return false;
list_add(&vma->evict_link, unwind);
return drm_mm_scan_add_block(scan, &vma->node);
}
static bool defer_evict(struct i915_vma *vma)
{
if (i915_vma_is_active(vma))
return true;
if (i915_vma_is_scanout(vma))
return true;
return false;
}
/**
* 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
* @color: color 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 long color,
u64 start, u64 end,
unsigned flags)
{
struct drm_mm_scan scan;
struct list_head eviction_list;
struct i915_vma *vma, *next;
struct drm_mm_node *node;
enum drm_mm_insert_mode mode;
struct i915_vma *active;
int ret;
lockdep_assert_held(&vm->mutex);
trace_i915_gem_evict(vm, min_size, alignment, flags);
/*
* The goal is to evict objects and amalgamate space in rough LRU order.
* Since both active and inactive objects reside on the same list,
* in a mix of creation and last scanned order, as we process the list
* we sort it into inactive/active, which keeps the active portion
* in a rough MRU order.
*
* The retirement sequence is thus:
* 1. Inactive objects (already retired, random order)
* 2. Active objects (will stall on unbinding, oldest scanned first)
*/
mode = DRM_MM_INSERT_BEST;
if (flags & PIN_HIGH)
mode = DRM_MM_INSERT_HIGH;
if (flags & PIN_MAPPABLE)
mode = DRM_MM_INSERT_LOW;
drm_mm_scan_init_with_range(&scan, &vm->mm,
min_size, alignment, color,
start, end, mode);
intel_gt_retire_requests(vm->gt);
search_again:
active = NULL;
INIT_LIST_HEAD(&eviction_list);
list_for_each_entry_safe(vma, next, &vm->bound_list, vm_link) {
if (vma == active) { /* now seen this vma twice */
if (flags & PIN_NONBLOCK)
break;
active = ERR_PTR(-EAGAIN);
}
/*
* We keep this list in a rough least-recently scanned order
* of active elements (inactive elements are cheap to reap).
* New entries are added to the end, and we move anything we
* scan to the end. The assumption is that the working set
* of applications is either steady state (and thanks to the
* userspace bo cache it almost always is) or volatile and
* frequently replaced after a frame, which are self-evicting!
* Given that assumption, the MRU order of the scan list is
* fairly static, and keeping it in least-recently scan order
* is suitable.
*
* To notice when we complete one full cycle, we record the
* first active element seen, before moving it to the tail.
*/
if (active != ERR_PTR(-EAGAIN) && defer_evict(vma)) {
if (!active)
active = vma;
list_move_tail(&vma->vm_link, &vm->bound_list);
continue;
}
if (mark_free(&scan, vma, flags, &eviction_list))
goto found;
}
/* Nothing found, clean up and bail out! */
list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
ret = drm_mm_scan_remove_block(&scan, &vma->node);
BUG_ON(ret);
}
/*
* 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;
/*
* Not everything in the GGTT is tracked via VMA using
* i915_vma_move_to_active(), otherwise we could evict as required
* with minimal stalling. Instead we are forced to idle the GPU and
* explicitly retire outstanding requests which will then remove
* the pinning for active objects such as contexts and ring,
* enabling us to evict them on the next iteration.
*
* To ensure that all user contexts are evictable, we perform
* a switch to the perma-pinned kernel context. This all also gives
* us a termination condition, when the last retired context is
* the kernel's there is no more we can evict.
*/
if (I915_SELFTEST_ONLY(igt_evict_ctl.fail_if_busy))
return -EBUSY;
ret = ggtt_flush(vm->gt);
if (ret)
return ret;
cond_resched();
flags |= PIN_NONBLOCK;
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, evict_link) {
if (drm_mm_scan_remove_block(&scan, &vma->node))
__i915_vma_pin(vma);
else
list_del(&vma->evict_link);
}
/* Unbinding will emit any required flushes */
ret = 0;
list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
__i915_vma_unpin(vma);
if (ret == 0)
ret = __i915_vma_unbind(vma);
}
while (ret == 0 && (node = drm_mm_scan_color_evict(&scan))) {
vma = container_of(node, struct i915_vma, node);
/* If we find any non-objects (!vma), we cannot evict them */
if (vma->node.color != I915_COLOR_UNEVICTABLE)
ret = __i915_vma_unbind(vma);
else
ret = -ENOSPC; /* XXX search failed, try again? */
}
return ret;
}
/**
* i915_gem_evict_for_node - Evict vmas to make room for binding a new one
* @vm: address space to evict from
* @target: range (and color) 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_node(struct i915_address_space *vm,
struct drm_mm_node *target,
unsigned int flags)
{
LIST_HEAD(eviction_list);
struct drm_mm_node *node;
u64 start = target->start;
u64 end = start + target->size;
struct i915_vma *vma, *next;
int ret = 0;
lockdep_assert_held(&vm->mutex);
GEM_BUG_ON(!IS_ALIGNED(start, I915_GTT_PAGE_SIZE));
GEM_BUG_ON(!IS_ALIGNED(end, I915_GTT_PAGE_SIZE));
trace_i915_gem_evict_node(vm, 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.
*/
intel_gt_retire_requests(vm->gt);
if (i915_vm_has_cache_coloring(vm)) {
/* Expand search to cover neighbouring guard pages (or lack!) */
if (start)
start -= I915_GTT_PAGE_SIZE;
/* Always look at the page afterwards to avoid the end-of-GTT */
end += I915_GTT_PAGE_SIZE;
}
GEM_BUG_ON(start >= end);
drm_mm_for_each_node_in_range(node, &vm->mm, start, end) {
/* If we find any non-objects (!vma), we cannot evict them */
if (node->color == I915_COLOR_UNEVICTABLE) {
ret = -ENOSPC;
break;
}
GEM_BUG_ON(!drm_mm_node_allocated(node));
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 (i915_vm_has_cache_coloring(vm)) {
if (node->start + node->size == target->start) {
if (node->color == target->color)
continue;
}
if (node->start == target->start + target->size) {
if (node->color == target->color)
continue;
}
}
if (i915_vma_is_pinned(vma)) {
ret = -ENOSPC;
break;
}
if (flags & PIN_NONBLOCK && i915_vma_is_active(vma)) {
ret = -ENOSPC;
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->evict_link, &eviction_list);
}
list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {
__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
*
* This function evicts all vmas from a vm.
*
* 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)
{
int ret = 0;
lockdep_assert_held(&vm->mutex);
trace_i915_gem_evict_vm(vm);
/* Switch back to the default context in order to unpin
* the existing context objects. However, such objects only
* pin themselves inside the global GTT and performing the
* switch otherwise is ineffective.
*/
if (i915_is_ggtt(vm)) {
ret = ggtt_flush(vm->gt);
if (ret)
return ret;
}
do {
struct i915_vma *vma, *vn;
LIST_HEAD(eviction_list);
list_for_each_entry(vma, &vm->bound_list, vm_link) {
if (i915_vma_is_pinned(vma))
continue;
__i915_vma_pin(vma);
list_add(&vma->evict_link, &eviction_list);
}
if (list_empty(&eviction_list))
break;
ret = 0;
list_for_each_entry_safe(vma, vn, &eviction_list, evict_link) {
__i915_vma_unpin(vma);
if (ret == 0)
ret = __i915_vma_unbind(vma);
if (ret != -EINTR) /* "Get me out of here!" */
ret = 0;
}
} while (ret == 0);
return ret;
}
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/i915_gem_evict.c"
#endif