512 lines
14 KiB
C
512 lines
14 KiB
C
|
/*
|
||
|
|
* SPDX-License-Identifier: MIT
|
||
|
|
*
|
||
|
|
* Copyright © 2018 Intel Corporation
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/mutex.h>
|
||
|
|
|
||
|
|
#include "i915_drv.h"
|
||
|
|
#include "i915_request.h"
|
||
|
|
#include "i915_scheduler.h"
|
||
|
|
|
||
|
|
static struct kmem_cache *slab_dependencies;
|
||
|
|
static struct kmem_cache *slab_priorities;
|
||
|
|
|
||
|
|
static DEFINE_SPINLOCK(schedule_lock);
|
||
|
|
|
||
|
|
static const struct i915_request *
|
||
|
|
node_to_request(const struct i915_sched_node *node)
|
||
|
|
{
|
||
|
|
return container_of(node, const struct i915_request, sched);
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline bool node_started(const struct i915_sched_node *node)
|
||
|
|
{
|
||
|
|
return i915_request_started(node_to_request(node));
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline bool node_signaled(const struct i915_sched_node *node)
|
||
|
|
{
|
||
|
|
return i915_request_completed(node_to_request(node));
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline struct i915_priolist *to_priolist(struct rb_node *rb)
|
||
|
|
{
|
||
|
|
return rb_entry(rb, struct i915_priolist, node);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void assert_priolists(struct i915_sched_engine * const sched_engine)
|
||
|
|
{
|
||
|
|
struct rb_node *rb;
|
||
|
|
long last_prio;
|
||
|
|
|
||
|
|
if (!IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
|
||
|
|
return;
|
||
|
|
|
||
|
|
GEM_BUG_ON(rb_first_cached(&sched_engine->queue) !=
|
||
|
|
rb_first(&sched_engine->queue.rb_root));
|
||
|
|
|
||
|
|
last_prio = INT_MAX;
|
||
|
|
for (rb = rb_first_cached(&sched_engine->queue); rb; rb = rb_next(rb)) {
|
||
|
|
const struct i915_priolist *p = to_priolist(rb);
|
||
|
|
|
||
|
|
GEM_BUG_ON(p->priority > last_prio);
|
||
|
|
last_prio = p->priority;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
struct list_head *
|
||
|
|
i915_sched_lookup_priolist(struct i915_sched_engine *sched_engine, int prio)
|
||
|
|
{
|
||
|
|
struct i915_priolist *p;
|
||
|
|
struct rb_node **parent, *rb;
|
||
|
|
bool first = true;
|
||
|
|
|
||
|
|
lockdep_assert_held(&sched_engine->lock);
|
||
|
|
assert_priolists(sched_engine);
|
||
|
|
|
||
|
|
if (unlikely(sched_engine->no_priolist))
|
||
|
|
prio = I915_PRIORITY_NORMAL;
|
||
|
|
|
||
|
|
find_priolist:
|
||
|
|
/* most positive priority is scheduled first, equal priorities fifo */
|
||
|
|
rb = NULL;
|
||
|
|
parent = &sched_engine->queue.rb_root.rb_node;
|
||
|
|
while (*parent) {
|
||
|
|
rb = *parent;
|
||
|
|
p = to_priolist(rb);
|
||
|
|
if (prio > p->priority) {
|
||
|
|
parent = &rb->rb_left;
|
||
|
|
} else if (prio < p->priority) {
|
||
|
|
parent = &rb->rb_right;
|
||
|
|
first = false;
|
||
|
|
} else {
|
||
|
|
return &p->requests;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if (prio == I915_PRIORITY_NORMAL) {
|
||
|
|
p = &sched_engine->default_priolist;
|
||
|
|
} else {
|
||
|
|
p = kmem_cache_alloc(slab_priorities, GFP_ATOMIC);
|
||
|
|
/* Convert an allocation failure to a priority bump */
|
||
|
|
if (unlikely(!p)) {
|
||
|
|
prio = I915_PRIORITY_NORMAL; /* recurses just once */
|
||
|
|
|
||
|
|
/* To maintain ordering with all rendering, after an
|
||
|
|
* allocation failure we have to disable all scheduling.
|
||
|
|
* Requests will then be executed in fifo, and schedule
|
||
|
|
* will ensure that dependencies are emitted in fifo.
|
||
|
|
* There will be still some reordering with existing
|
||
|
|
* requests, so if userspace lied about their
|
||
|
|
* dependencies that reordering may be visible.
|
||
|
|
*/
|
||
|
|
sched_engine->no_priolist = true;
|
||
|
|
goto find_priolist;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
p->priority = prio;
|
||
|
|
INIT_LIST_HEAD(&p->requests);
|
||
|
|
|
||
|
|
rb_link_node(&p->node, rb, parent);
|
||
|
|
rb_insert_color_cached(&p->node, &sched_engine->queue, first);
|
||
|
|
|
||
|
|
return &p->requests;
|
||
|
|
}
|
||
|
|
|
||
|
|
void __i915_priolist_free(struct i915_priolist *p)
|
||
|
|
{
|
||
|
|
kmem_cache_free(slab_priorities, p);
|
||
|
|
}
|
||
|
|
|
||
|
|
struct sched_cache {
|
||
|
|
struct list_head *priolist;
|
||
|
|
};
|
||
|
|
|
||
|
|
static struct i915_sched_engine *
|
||
|
|
lock_sched_engine(struct i915_sched_node *node,
|
||
|
|
struct i915_sched_engine *locked,
|
||
|
|
struct sched_cache *cache)
|
||
|
|
{
|
||
|
|
const struct i915_request *rq = node_to_request(node);
|
||
|
|
struct i915_sched_engine *sched_engine;
|
||
|
|
|
||
|
|
GEM_BUG_ON(!locked);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Virtual engines complicate acquiring the engine timeline lock,
|
||
|
|
* as their rq->engine pointer is not stable until under that
|
||
|
|
* engine lock. The simple ploy we use is to take the lock then
|
||
|
|
* check that the rq still belongs to the newly locked engine.
|
||
|
|
*/
|
||
|
|
while (locked != (sched_engine = READ_ONCE(rq->engine)->sched_engine)) {
|
||
|
|
spin_unlock(&locked->lock);
|
||
|
|
memset(cache, 0, sizeof(*cache));
|
||
|
|
spin_lock(&sched_engine->lock);
|
||
|
|
locked = sched_engine;
|
||
|
|
}
|
||
|
|
|
||
|
|
GEM_BUG_ON(locked != sched_engine);
|
||
|
|
return locked;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __i915_schedule(struct i915_sched_node *node,
|
||
|
|
const struct i915_sched_attr *attr)
|
||
|
|
{
|
||
|
|
const int prio = max(attr->priority, node->attr.priority);
|
||
|
|
struct i915_sched_engine *sched_engine;
|
||
|
|
struct i915_dependency *dep, *p;
|
||
|
|
struct i915_dependency stack;
|
||
|
|
struct sched_cache cache;
|
||
|
|
LIST_HEAD(dfs);
|
||
|
|
|
||
|
|
/* Needed in order to use the temporary link inside i915_dependency */
|
||
|
|
lockdep_assert_held(&schedule_lock);
|
||
|
|
GEM_BUG_ON(prio == I915_PRIORITY_INVALID);
|
||
|
|
|
||
|
|
if (node_signaled(node))
|
||
|
|
return;
|
||
|
|
|
||
|
|
stack.signaler = node;
|
||
|
|
list_add(&stack.dfs_link, &dfs);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Recursively bump all dependent priorities to match the new request.
|
||
|
|
*
|
||
|
|
* A naive approach would be to use recursion:
|
||
|
|
* static void update_priorities(struct i915_sched_node *node, prio) {
|
||
|
|
* list_for_each_entry(dep, &node->signalers_list, signal_link)
|
||
|
|
* update_priorities(dep->signal, prio)
|
||
|
|
* queue_request(node);
|
||
|
|
* }
|
||
|
|
* but that may have unlimited recursion depth and so runs a very
|
||
|
|
* real risk of overunning the kernel stack. Instead, we build
|
||
|
|
* a flat list of all dependencies starting with the current request.
|
||
|
|
* As we walk the list of dependencies, we add all of its dependencies
|
||
|
|
* to the end of the list (this may include an already visited
|
||
|
|
* request) and continue to walk onwards onto the new dependencies. The
|
||
|
|
* end result is a topological list of requests in reverse order, the
|
||
|
|
* last element in the list is the request we must execute first.
|
||
|
|
*/
|
||
|
|
list_for_each_entry(dep, &dfs, dfs_link) {
|
||
|
|
struct i915_sched_node *node = dep->signaler;
|
||
|
|
|
||
|
|
/* If we are already flying, we know we have no signalers */
|
||
|
|
if (node_started(node))
|
||
|
|
continue;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Within an engine, there can be no cycle, but we may
|
||
|
|
* refer to the same dependency chain multiple times
|
||
|
|
* (redundant dependencies are not eliminated) and across
|
||
|
|
* engines.
|
||
|
|
*/
|
||
|
|
list_for_each_entry(p, &node->signalers_list, signal_link) {
|
||
|
|
GEM_BUG_ON(p == dep); /* no cycles! */
|
||
|
|
|
||
|
|
if (node_signaled(p->signaler))
|
||
|
|
continue;
|
||
|
|
|
||
|
|
if (prio > READ_ONCE(p->signaler->attr.priority))
|
||
|
|
list_move_tail(&p->dfs_link, &dfs);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* If we didn't need to bump any existing priorities, and we haven't
|
||
|
|
* yet submitted this request (i.e. there is no potential race with
|
||
|
|
* execlists_submit_request()), we can set our own priority and skip
|
||
|
|
* acquiring the engine locks.
|
||
|
|
*/
|
||
|
|
if (node->attr.priority == I915_PRIORITY_INVALID) {
|
||
|
|
GEM_BUG_ON(!list_empty(&node->link));
|
||
|
|
node->attr = *attr;
|
||
|
|
|
||
|
|
if (stack.dfs_link.next == stack.dfs_link.prev)
|
||
|
|
return;
|
||
|
|
|
||
|
|
__list_del_entry(&stack.dfs_link);
|
||
|
|
}
|
||
|
|
|
||
|
|
memset(&cache, 0, sizeof(cache));
|
||
|
|
sched_engine = node_to_request(node)->engine->sched_engine;
|
||
|
|
spin_lock(&sched_engine->lock);
|
||
|
|
|
||
|
|
/* Fifo and depth-first replacement ensure our deps execute before us */
|
||
|
|
sched_engine = lock_sched_engine(node, sched_engine, &cache);
|
||
|
|
list_for_each_entry_safe_reverse(dep, p, &dfs, dfs_link) {
|
||
|
|
struct i915_request *from = container_of(dep->signaler,
|
||
|
|
struct i915_request,
|
||
|
|
sched);
|
||
|
|
INIT_LIST_HEAD(&dep->dfs_link);
|
||
|
|
|
||
|
|
node = dep->signaler;
|
||
|
|
sched_engine = lock_sched_engine(node, sched_engine, &cache);
|
||
|
|
lockdep_assert_held(&sched_engine->lock);
|
||
|
|
|
||
|
|
/* Recheck after acquiring the engine->timeline.lock */
|
||
|
|
if (prio <= node->attr.priority || node_signaled(node))
|
||
|
|
continue;
|
||
|
|
|
||
|
|
GEM_BUG_ON(node_to_request(node)->engine->sched_engine !=
|
||
|
|
sched_engine);
|
||
|
|
|
||
|
|
/* Must be called before changing the nodes priority */
|
||
|
|
if (sched_engine->bump_inflight_request_prio)
|
||
|
|
sched_engine->bump_inflight_request_prio(from, prio);
|
||
|
|
|
||
|
|
WRITE_ONCE(node->attr.priority, prio);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Once the request is ready, it will be placed into the
|
||
|
|
* priority lists and then onto the HW runlist. Before the
|
||
|
|
* request is ready, it does not contribute to our preemption
|
||
|
|
* decisions and we can safely ignore it, as it will, and
|
||
|
|
* any preemption required, be dealt with upon submission.
|
||
|
|
* See engine->submit_request()
|
||
|
|
*/
|
||
|
|
if (list_empty(&node->link))
|
||
|
|
continue;
|
||
|
|
|
||
|
|
if (i915_request_in_priority_queue(node_to_request(node))) {
|
||
|
|
if (!cache.priolist)
|
||
|
|
cache.priolist =
|
||
|
|
i915_sched_lookup_priolist(sched_engine,
|
||
|
|
prio);
|
||
|
|
list_move_tail(&node->link, cache.priolist);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Defer (tasklet) submission until after all of our updates. */
|
||
|
|
if (sched_engine->kick_backend)
|
||
|
|
sched_engine->kick_backend(node_to_request(node), prio);
|
||
|
|
}
|
||
|
|
|
||
|
|
spin_unlock(&sched_engine->lock);
|
||
|
|
}
|
||
|
|
|
||
|
|
void i915_schedule(struct i915_request *rq, const struct i915_sched_attr *attr)
|
||
|
|
{
|
||
|
|
spin_lock_irq(&schedule_lock);
|
||
|
|
__i915_schedule(&rq->sched, attr);
|
||
|
|
spin_unlock_irq(&schedule_lock);
|
||
|
|
}
|
||
|
|
|
||
|
|
void i915_sched_node_init(struct i915_sched_node *node)
|
||
|
|
{
|
||
|
|
INIT_LIST_HEAD(&node->signalers_list);
|
||
|
|
INIT_LIST_HEAD(&node->waiters_list);
|
||
|
|
INIT_LIST_HEAD(&node->link);
|
||
|
|
|
||
|
|
i915_sched_node_reinit(node);
|
||
|
|
}
|
||
|
|
|
||
|
|
void i915_sched_node_reinit(struct i915_sched_node *node)
|
||
|
|
{
|
||
|
|
node->attr.priority = I915_PRIORITY_INVALID;
|
||
|
|
node->semaphores = 0;
|
||
|
|
node->flags = 0;
|
||
|
|
|
||
|
|
GEM_BUG_ON(!list_empty(&node->signalers_list));
|
||
|
|
GEM_BUG_ON(!list_empty(&node->waiters_list));
|
||
|
|
GEM_BUG_ON(!list_empty(&node->link));
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct i915_dependency *
|
||
|
|
i915_dependency_alloc(void)
|
||
|
|
{
|
||
|
|
return kmem_cache_alloc(slab_dependencies, GFP_KERNEL);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void
|
||
|
|
i915_dependency_free(struct i915_dependency *dep)
|
||
|
|
{
|
||
|
|
kmem_cache_free(slab_dependencies, dep);
|
||
|
|
}
|
||
|
|
|
||
|
|
bool __i915_sched_node_add_dependency(struct i915_sched_node *node,
|
||
|
|
struct i915_sched_node *signal,
|
||
|
|
struct i915_dependency *dep,
|
||
|
|
unsigned long flags)
|
||
|
|
{
|
||
|
|
bool ret = false;
|
||
|
|
|
||
|
|
spin_lock_irq(&schedule_lock);
|
||
|
|
|
||
|
|
if (!node_signaled(signal)) {
|
||
|
|
INIT_LIST_HEAD(&dep->dfs_link);
|
||
|
|
dep->signaler = signal;
|
||
|
|
dep->waiter = node;
|
||
|
|
dep->flags = flags;
|
||
|
|
|
||
|
|
/* All set, now publish. Beware the lockless walkers. */
|
||
|
|
list_add_rcu(&dep->signal_link, &node->signalers_list);
|
||
|
|
list_add_rcu(&dep->wait_link, &signal->waiters_list);
|
||
|
|
|
||
|
|
/* Propagate the chains */
|
||
|
|
node->flags |= signal->flags;
|
||
|
|
ret = true;
|
||
|
|
}
|
||
|
|
|
||
|
|
spin_unlock_irq(&schedule_lock);
|
||
|
|
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
int i915_sched_node_add_dependency(struct i915_sched_node *node,
|
||
|
|
struct i915_sched_node *signal,
|
||
|
|
unsigned long flags)
|
||
|
|
{
|
||
|
|
struct i915_dependency *dep;
|
||
|
|
|
||
|
|
dep = i915_dependency_alloc();
|
||
|
|
if (!dep)
|
||
|
|
return -ENOMEM;
|
||
|
|
|
||
|
|
if (!__i915_sched_node_add_dependency(node, signal, dep,
|
||
|
|
flags | I915_DEPENDENCY_ALLOC))
|
||
|
|
i915_dependency_free(dep);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
void i915_sched_node_fini(struct i915_sched_node *node)
|
||
|
|
{
|
||
|
|
struct i915_dependency *dep, *tmp;
|
||
|
|
|
||
|
|
spin_lock_irq(&schedule_lock);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Everyone we depended upon (the fences we wait to be signaled)
|
||
|
|
* should retire before us and remove themselves from our list.
|
||
|
|
* However, retirement is run independently on each timeline and
|
||
|
|
* so we may be called out-of-order.
|
||
|
|
*/
|
||
|
|
list_for_each_entry_safe(dep, tmp, &node->signalers_list, signal_link) {
|
||
|
|
GEM_BUG_ON(!list_empty(&dep->dfs_link));
|
||
|
|
|
||
|
|
list_del_rcu(&dep->wait_link);
|
||
|
|
if (dep->flags & I915_DEPENDENCY_ALLOC)
|
||
|
|
i915_dependency_free(dep);
|
||
|
|
}
|
||
|
|
INIT_LIST_HEAD(&node->signalers_list);
|
||
|
|
|
||
|
|
/* Remove ourselves from everyone who depends upon us */
|
||
|
|
list_for_each_entry_safe(dep, tmp, &node->waiters_list, wait_link) {
|
||
|
|
GEM_BUG_ON(dep->signaler != node);
|
||
|
|
GEM_BUG_ON(!list_empty(&dep->dfs_link));
|
||
|
|
|
||
|
|
list_del_rcu(&dep->signal_link);
|
||
|
|
if (dep->flags & I915_DEPENDENCY_ALLOC)
|
||
|
|
i915_dependency_free(dep);
|
||
|
|
}
|
||
|
|
INIT_LIST_HEAD(&node->waiters_list);
|
||
|
|
|
||
|
|
spin_unlock_irq(&schedule_lock);
|
||
|
|
}
|
||
|
|
|
||
|
|
void i915_request_show_with_schedule(struct drm_printer *m,
|
||
|
|
const struct i915_request *rq,
|
||
|
|
const char *prefix,
|
||
|
|
int indent)
|
||
|
|
{
|
||
|
|
struct i915_dependency *dep;
|
||
|
|
|
||
|
|
i915_request_show(m, rq, prefix, indent);
|
||
|
|
if (i915_request_completed(rq))
|
||
|
|
return;
|
||
|
|
|
||
|
|
rcu_read_lock();
|
||
|
|
for_each_signaler(dep, rq) {
|
||
|
|
const struct i915_request *signaler =
|
||
|
|
node_to_request(dep->signaler);
|
||
|
|
|
||
|
|
/* Dependencies along the same timeline are expected. */
|
||
|
|
if (signaler->timeline == rq->timeline)
|
||
|
|
continue;
|
||
|
|
|
||
|
|
if (__i915_request_is_complete(signaler))
|
||
|
|
continue;
|
||
|
|
|
||
|
|
i915_request_show(m, signaler, prefix, indent + 2);
|
||
|
|
}
|
||
|
|
rcu_read_unlock();
|
||
|
|
}
|
||
|
|
|
||
|
|
static void default_destroy(struct kref *kref)
|
||
|
|
{
|
||
|
|
struct i915_sched_engine *sched_engine =
|
||
|
|
container_of(kref, typeof(*sched_engine), ref);
|
||
|
|
|
||
|
|
tasklet_kill(&sched_engine->tasklet); /* flush the callback */
|
||
|
|
kfree(sched_engine);
|
||
|
|
}
|
||
|
|
|
||
|
|
static bool default_disabled(struct i915_sched_engine *sched_engine)
|
||
|
|
{
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
struct i915_sched_engine *
|
||
|
|
i915_sched_engine_create(unsigned int subclass)
|
||
|
|
{
|
||
|
|
struct i915_sched_engine *sched_engine;
|
||
|
|
|
||
|
|
sched_engine = kzalloc(sizeof(*sched_engine), GFP_KERNEL);
|
||
|
|
if (!sched_engine)
|
||
|
|
return NULL;
|
||
|
|
|
||
|
|
kref_init(&sched_engine->ref);
|
||
|
|
|
||
|
|
sched_engine->queue = RB_ROOT_CACHED;
|
||
|
|
sched_engine->queue_priority_hint = INT_MIN;
|
||
|
|
sched_engine->destroy = default_destroy;
|
||
|
|
sched_engine->disabled = default_disabled;
|
||
|
|
|
||
|
|
INIT_LIST_HEAD(&sched_engine->requests);
|
||
|
|
INIT_LIST_HEAD(&sched_engine->hold);
|
||
|
|
|
||
|
|
spin_lock_init(&sched_engine->lock);
|
||
|
|
lockdep_set_subclass(&sched_engine->lock, subclass);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Due to an interesting quirk in lockdep's internal debug tracking,
|
||
|
|
* after setting a subclass we must ensure the lock is used. Otherwise,
|
||
|
|
* nr_unused_locks is incremented once too often.
|
||
|
|
*/
|
||
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
||
|
|
local_irq_disable();
|
||
|
|
lock_map_acquire(&sched_engine->lock.dep_map);
|
||
|
|
lock_map_release(&sched_engine->lock.dep_map);
|
||
|
|
local_irq_enable();
|
||
|
|
#endif
|
||
|
|
|
||
|
|
return sched_engine;
|
||
|
|
}
|
||
|
|
|
||
|
|
void i915_scheduler_module_exit(void)
|
||
|
|
{
|
||
|
|
kmem_cache_destroy(slab_dependencies);
|
||
|
|
kmem_cache_destroy(slab_priorities);
|
||
|
|
}
|
||
|
|
|
||
|
|
int __init i915_scheduler_module_init(void)
|
||
|
|
{
|
||
|
|
slab_dependencies = KMEM_CACHE(i915_dependency,
|
||
|
|
SLAB_HWCACHE_ALIGN |
|
||
|
|
SLAB_TYPESAFE_BY_RCU);
|
||
|
|
if (!slab_dependencies)
|
||
|
|
return -ENOMEM;
|
||
|
|
|
||
|
|
slab_priorities = KMEM_CACHE(i915_priolist, 0);
|
||
|
|
if (!slab_priorities)
|
||
|
|
goto err_priorities;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
err_priorities:
|
||
|
|
kmem_cache_destroy(slab_priorities);
|
||
|
|
return -ENOMEM;
|
||
|
|
}
|