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/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#include <linux/workqueue.h>
#include "i915_drv.h" /* for_each_engine() */
#include "i915_request.h"
#include "intel_gt.h"
#include "intel_gt_pm.h"
#include "intel_gt_requests.h"
#include "intel_timeline.h"
static void retire_requests(struct intel_timeline *tl)
{
struct i915_request *rq, *rn;
list_for_each_entry_safe(rq, rn, &tl->requests, link)
if (!i915_request_retire(rq))
break;
}
static void flush_submission(struct intel_gt *gt)
{
struct intel_engine_cs *engine;
enum intel_engine_id id;
for_each_engine(engine, gt, id)
intel_engine_flush_submission(engine);
}
static void engine_retire(struct work_struct *work)
{
struct intel_engine_cs *engine =
container_of(work, typeof(*engine), retire_work);
struct intel_timeline *tl = xchg(&engine->retire, NULL);
do {
struct intel_timeline *next = xchg(&tl->retire, NULL);
/*
* Our goal here is to retire _idle_ timelines as soon as
* possible (as they are idle, we do not expect userspace
* to be cleaning up anytime soon).
*
* If the timeline is currently locked, either it is being
* retired elsewhere or about to be!
*/
if (mutex_trylock(&tl->mutex)) {
retire_requests(tl);
mutex_unlock(&tl->mutex);
}
intel_timeline_put(tl);
GEM_BUG_ON(!next);
tl = ptr_mask_bits(next, 1);
} while (tl);
}
static bool add_retire(struct intel_engine_cs *engine,
struct intel_timeline *tl)
{
struct intel_timeline *first;
/*
* We open-code a llist here to include the additional tag [BIT(0)]
* so that we know when the timeline is already on a
* retirement queue: either this engine or another.
*
* However, we rely on that a timeline can only be active on a single
* engine at any one time and that add_retire() is called before the
* engine releases the timeline and transferred to another to retire.
*/
if (READ_ONCE(tl->retire)) /* already queued */
return false;
intel_timeline_get(tl);
first = READ_ONCE(engine->retire);
do
tl->retire = ptr_pack_bits(first, 1, 1);
while (!try_cmpxchg(&engine->retire, &first, tl));
return !first;
}
void intel_engine_add_retire(struct intel_engine_cs *engine,
struct intel_timeline *tl)
{
if (add_retire(engine, tl))
schedule_work(&engine->retire_work);
}
void intel_engine_init_retire(struct intel_engine_cs *engine)
{
INIT_WORK(&engine->retire_work, engine_retire);
}
void intel_engine_fini_retire(struct intel_engine_cs *engine)
{
flush_work(&engine->retire_work);
GEM_BUG_ON(engine->retire);
}
long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout)
{
struct intel_gt_timelines *timelines = >->timelines;
struct intel_timeline *tl, *tn;
unsigned long active_count = 0;
bool interruptible;
LIST_HEAD(free);
interruptible = true;
if (unlikely(timeout < 0))
timeout = -timeout, interruptible = false;
flush_submission(gt); /* kick the ksoftirqd tasklets */
spin_lock(&timelines->lock);
list_for_each_entry_safe(tl, tn, &timelines->active_list, link) {
if (!mutex_trylock(&tl->mutex)) {
active_count++; /* report busy to caller, try again? */
continue;
}
intel_timeline_get(tl);
GEM_BUG_ON(!atomic_read(&tl->active_count));
atomic_inc(&tl->active_count); /* pin the list element */
spin_unlock(&timelines->lock);
if (timeout > 0) {
struct dma_fence *fence;
fence = i915_active_fence_get(&tl->last_request);
if (fence) {
timeout = dma_fence_wait_timeout(fence,
interruptible,
timeout);
dma_fence_put(fence);
}
}
retire_requests(tl);
spin_lock(&timelines->lock);
/* Resume iteration after dropping lock */
list_safe_reset_next(tl, tn, link);
if (atomic_dec_and_test(&tl->active_count))
list_del(&tl->link);
else
active_count += !!rcu_access_pointer(tl->last_request.fence);
mutex_unlock(&tl->mutex);
/* Defer the final release to after the spinlock */
if (refcount_dec_and_test(&tl->kref.refcount)) {
GEM_BUG_ON(atomic_read(&tl->active_count));
list_add(&tl->link, &free);
}
}
spin_unlock(&timelines->lock);
list_for_each_entry_safe(tl, tn, &free, link)
__intel_timeline_free(&tl->kref);
return active_count ? timeout : 0;
}
int intel_gt_wait_for_idle(struct intel_gt *gt, long timeout)
{
/* If the device is asleep, we have no requests outstanding */
if (!intel_gt_pm_is_awake(gt))
return 0;
while ((timeout = intel_gt_retire_requests_timeout(gt, timeout)) > 0) {
cond_resched();
if (signal_pending(current))
return -EINTR;
}
return timeout;
}
static void retire_work_handler(struct work_struct *work)
{
struct intel_gt *gt =
container_of(work, typeof(*gt), requests.retire_work.work);
schedule_delayed_work(>->requests.retire_work,
round_jiffies_up_relative(HZ));
intel_gt_retire_requests(gt);
}
void intel_gt_init_requests(struct intel_gt *gt)
{
INIT_DELAYED_WORK(>->requests.retire_work, retire_work_handler);
}
void intel_gt_park_requests(struct intel_gt *gt)
{
cancel_delayed_work(>->requests.retire_work);
}
void intel_gt_unpark_requests(struct intel_gt *gt)
{
schedule_delayed_work(>->requests.retire_work,
round_jiffies_up_relative(HZ));
}
void intel_gt_fini_requests(struct intel_gt *gt)
{
/* Wait until the work is marked as finished before unloading! */
cancel_delayed_work_sync(>->requests.retire_work);
}
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