/*
* 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"
I915_SELFTEST_DECLARE(static struct igt_evict_ctl {
bool fail_if_busy:1;
} igt_evict_ctl;)
static bool ggtt_is_idle(struct drm_i915_private *i915)
{
struct intel_engine_cs *engine;
enum intel_engine_id id;
if (i915->gt.active_requests)
return false;
for_each_engine(engine, i915, id) {
if (!intel_engine_has_kernel_context(engine))
return false;
}
return true;
}
static int ggtt_flush(struct drm_i915_private *i915)
{
int err;
/* 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.
*/
err = i915_gem_switch_to_kernel_context(i915);
if (err)
return err;
err = i915_gem_wait_for_idle(i915,
I915_WAIT_INTERRUPTIBLE |
I915_WAIT_LOCKED,
MAX_SCHEDULE_TIMEOUT);
if (err)
return err;
GEM_BUG_ON(!ggtt_is_idle(i915));
return 0;
}
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;
if (flags & PIN_NONFAULT && i915_vma_has_userfault(vma))
return false;
list_add(&vma->evict_link, unwind);
return drm_mm_scan_add_block(scan, &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 drm_mm_scan scan;
struct list_head eviction_list;
struct list_head *phases[] = {
&vm->inactive_list,
&vm->active_list,
NULL,
}, **phase;
struct i915_vma *vma, *next;
struct drm_mm_node *node;
enum drm_mm_insert_mode mode;
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.
*/
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, cache_level,
start, end, mode);
/*
* 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_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(&scan, vma, flags, &eviction_list))
goto found;
} while (*++phase);
/* 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 (!ggtt_is_idle(dev_priv)) {
if (I915_SELFTEST_ONLY(igt_evict_ctl.fail_if_busy))
return -EBUSY;
ret = ggtt_flush(dev_priv);
if (ret)
return ret;
cond_resched();
goto search_again;
}
/*
* 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;
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);
ret = i915_vma_unbind(vma);
}
return ret;
}
/**
* i915_gem_evict_for_vma - 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;
bool check_color;
int ret = 0;
lockdep_assert_held(&vm->i915->drm.struct_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.
*/
if (!(flags & PIN_NONBLOCK))
i915_retire_requests(vm->i915);
check_color = vm->mm.color_adjust;
if (check_color) {
/* 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(!node->allocated);
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 (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 (flags & PIN_NONBLOCK &&
(i915_vma_is_pinned(vma) || i915_vma_is_active(vma))) {
ret = -ENOSPC;
break;
}
if (flags & PIN_NONFAULT && i915_vma_has_userfault(vma)) {
ret = -ENOSPC;
break;
}
/* Overlap of objects in the same batch? */
if (i915_vma_is_pinned(vma)) {
ret = -ENOSPC;
if (vma->exec_flags &&
*vma->exec_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->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)
{
struct list_head *phases[] = {
&vm->inactive_list,
&vm->active_list,
NULL
}, **phase;
struct list_head eviction_list;
struct i915_vma *vma, *next;
int ret;
lockdep_assert_held(&vm->i915->drm.struct_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->i915);
if (ret)
return ret;
}
INIT_LIST_HEAD(&eviction_list);
phase = phases;
do {
list_for_each_entry(vma, *phase, vm_link) {
if (i915_vma_is_pinned(vma))
continue;
__i915_vma_pin(vma);
list_add(&vma->evict_link, &eviction_list);
}
} while (*++phase);
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);
}
return ret;
}
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/i915_gem_evict.c"
#endif
