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/*
* Copyright © 2015 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.
*
*/
#include <linux/kthread.h>
#include <uapi/linux/sched/types.h>
#include "i915_drv.h"
#define task_asleep(tsk) ((tsk)->state & TASK_NORMAL && !(tsk)->on_rq)
static void irq_enable(struct intel_engine_cs *engine)
{
if (!engine->irq_enable)
return;
/* Caller disables interrupts */
spin_lock(&engine->i915->irq_lock);
engine->irq_enable(engine);
spin_unlock(&engine->i915->irq_lock);
}
static void irq_disable(struct intel_engine_cs *engine)
{
if (!engine->irq_disable)
return;
/* Caller disables interrupts */
spin_lock(&engine->i915->irq_lock);
engine->irq_disable(engine);
spin_unlock(&engine->i915->irq_lock);
}
static void __intel_breadcrumbs_disarm_irq(struct intel_breadcrumbs *b)
{
lockdep_assert_held(&b->irq_lock);
GEM_BUG_ON(!b->irq_enabled);
if (!--b->irq_enabled)
irq_disable(container_of(b,
struct intel_engine_cs,
breadcrumbs));
b->irq_armed = false;
}
void intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine)
{
struct intel_breadcrumbs *b = &engine->breadcrumbs;
if (!b->irq_armed)
return;
spin_lock_irq(&b->irq_lock);
if (b->irq_armed)
__intel_breadcrumbs_disarm_irq(b);
spin_unlock_irq(&b->irq_lock);
}
static inline bool __request_completed(const struct i915_request *rq)
{
return i915_seqno_passed(__hwsp_seqno(rq), rq->fence.seqno);
}
bool intel_engine_breadcrumbs_irq(struct intel_engine_cs *engine)
{
struct intel_breadcrumbs *b = &engine->breadcrumbs;
struct intel_context *ce, *cn;
struct list_head *pos, *next;
LIST_HEAD(signal);
spin_lock(&b->irq_lock);
b->irq_fired = true;
if (b->irq_armed && list_empty(&b->signalers))
__intel_breadcrumbs_disarm_irq(b);
list_for_each_entry_safe(ce, cn, &b->signalers, signal_link) {
GEM_BUG_ON(list_empty(&ce->signals));
list_for_each_safe(pos, next, &ce->signals) {
struct i915_request *rq =
list_entry(pos, typeof(*rq), signal_link);
if (!__request_completed(rq))
break;
GEM_BUG_ON(!test_bit(I915_FENCE_FLAG_SIGNAL,
&rq->fence.flags));
clear_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags);
/*
* We may race with direct invocation of
* dma_fence_signal(), e.g. i915_request_retire(),
* in which case we can skip processing it ourselves.
*/
if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
&rq->fence.flags))
continue;
/*
* Queue for execution after dropping the signaling
* spinlock as the callback chain may end up adding
* more signalers to the same context or engine.
*/
i915_request_get(rq);
list_add_tail(&rq->signal_link, &signal);
}
/*
* We process the list deletion in bulk, only using a list_add
* (not list_move) above but keeping the status of
* rq->signal_link known with the I915_FENCE_FLAG_SIGNAL bit.
*/
if (!list_is_first(pos, &ce->signals)) {
/* Advance the list to the first incomplete request */
__list_del_many(&ce->signals, pos);
if (&ce->signals == pos) /* now empty */
list_del_init(&ce->signal_link);
}
}
spin_unlock(&b->irq_lock);
list_for_each_safe(pos, next, &signal) {
struct i915_request *rq =
list_entry(pos, typeof(*rq), signal_link);
dma_fence_signal(&rq->fence);
i915_request_put(rq);
}
return !list_empty(&signal);
}
bool intel_engine_signal_breadcrumbs(struct intel_engine_cs *engine)
{
bool result;
local_irq_disable();
result = intel_engine_breadcrumbs_irq(engine);
local_irq_enable();
return result;
}
static void signal_irq_work(struct irq_work *work)
{
struct intel_engine_cs *engine =
container_of(work, typeof(*engine), breadcrumbs.irq_work);
intel_engine_breadcrumbs_irq(engine);
}
static unsigned long wait_timeout(void)
{
return round_jiffies_up(jiffies + DRM_I915_HANGCHECK_JIFFIES);
}
static noinline void missed_breadcrumb(struct intel_engine_cs *engine)
{
if (GEM_SHOW_DEBUG()) {
struct drm_printer p = drm_debug_printer(__func__);
intel_engine_dump(engine, &p,
"%s missed breadcrumb at %pS\n",
engine->name, __builtin_return_address(0));
}
set_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings);
}
static void intel_breadcrumbs_hangcheck(struct timer_list *t)
{
struct intel_engine_cs *engine =
from_timer(engine, t, breadcrumbs.hangcheck);
struct intel_breadcrumbs *b = &engine->breadcrumbs;
if (!b->irq_armed)
return;
if (b->irq_fired)
goto rearm;
/*
* We keep the hangcheck timer alive until we disarm the irq, even
* if there are no waiters at present.
*
* If the waiter was currently running, assume it hasn't had a chance
* to process the pending interrupt (e.g, low priority task on a loaded
* system) and wait until it sleeps before declaring a missed interrupt.
*
* If the waiter was asleep (and not even pending a wakeup), then we
* must have missed an interrupt as the GPU has stopped advancing
* but we still have a waiter. Assuming all batches complete within
* DRM_I915_HANGCHECK_JIFFIES [1.5s]!
*/
synchronize_hardirq(engine->i915->drm.irq);
if (intel_engine_signal_breadcrumbs(engine)) {
missed_breadcrumb(engine);
mod_timer(&b->fake_irq, jiffies + 1);
} else {
rearm:
b->irq_fired = false;
mod_timer(&b->hangcheck, wait_timeout());
}
}
static void intel_breadcrumbs_fake_irq(struct timer_list *t)
{
struct intel_engine_cs *engine =
from_timer(engine, t, breadcrumbs.fake_irq);
struct intel_breadcrumbs *b = &engine->breadcrumbs;
/*
* The timer persists in case we cannot enable interrupts,
* or if we have previously seen seqno/interrupt incoherency
* ("missed interrupt" syndrome, better known as a "missed breadcrumb").
* Here the worker will wake up every jiffie in order to kick the
* oldest waiter to do the coherent seqno check.
*/
if (!intel_engine_signal_breadcrumbs(engine) && !b->irq_armed)
return;
/* If the user has disabled the fake-irq, restore the hangchecking */
if (!test_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings)) {
mod_timer(&b->hangcheck, wait_timeout());
return;
}
mod_timer(&b->fake_irq, jiffies + 1);
}
void intel_engine_pin_breadcrumbs_irq(struct intel_engine_cs *engine)
{
struct intel_breadcrumbs *b = &engine->breadcrumbs;
spin_lock_irq(&b->irq_lock);
if (!b->irq_enabled++)
irq_enable(engine);
GEM_BUG_ON(!b->irq_enabled); /* no overflow! */
spin_unlock_irq(&b->irq_lock);
}
void intel_engine_unpin_breadcrumbs_irq(struct intel_engine_cs *engine)
{
struct intel_breadcrumbs *b = &engine->breadcrumbs;
spin_lock_irq(&b->irq_lock);
GEM_BUG_ON(!b->irq_enabled); /* no underflow! */
if (!--b->irq_enabled)
irq_disable(engine);
spin_unlock_irq(&b->irq_lock);
}
static bool use_fake_irq(const struct intel_breadcrumbs *b)
{
const struct intel_engine_cs *engine =
container_of(b, struct intel_engine_cs, breadcrumbs);
if (!test_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings))
return false;
/*
* Only start with the heavy weight fake irq timer if we have not
* seen any interrupts since enabling it the first time. If the
* interrupts are still arriving, it means we made a mistake in our
* engine->seqno_barrier(), a timing error that should be transient
* and unlikely to reoccur.
*/
return !b->irq_fired;
}
static void enable_fake_irq(struct intel_breadcrumbs *b)
{
/* Ensure we never sleep indefinitely */
if (!b->irq_enabled || use_fake_irq(b))
mod_timer(&b->fake_irq, jiffies + 1);
else
mod_timer(&b->hangcheck, wait_timeout());
}
static bool __intel_breadcrumbs_arm_irq(struct intel_breadcrumbs *b)
{
struct intel_engine_cs *engine =
container_of(b, struct intel_engine_cs, breadcrumbs);
struct drm_i915_private *i915 = engine->i915;
bool enabled;
lockdep_assert_held(&b->irq_lock);
if (b->irq_armed)
return false;
/*
* The breadcrumb irq will be disarmed on the interrupt after the
* waiters are signaled. This gives us a single interrupt window in
* which we can add a new waiter and avoid the cost of re-enabling
* the irq.
*/
b->irq_armed = true;
/*
* Since we are waiting on a request, the GPU should be busy
* and should have its own rpm reference. This is tracked
* by i915->gt.awake, we can forgo holding our own wakref
* for the interrupt as before i915->gt.awake is released (when
* the driver is idle) we disarm the breadcrumbs.
*/
/* No interrupts? Kick the waiter every jiffie! */
enabled = false;
if (!b->irq_enabled++ &&
!test_bit(engine->id, &i915->gpu_error.test_irq_rings)) {
irq_enable(engine);
enabled = true;
}
enable_fake_irq(b);
return enabled;
}
void intel_engine_init_breadcrumbs(struct intel_engine_cs *engine)
{
struct intel_breadcrumbs *b = &engine->breadcrumbs;
spin_lock_init(&b->irq_lock);
INIT_LIST_HEAD(&b->signalers);
init_irq_work(&b->irq_work, signal_irq_work);
timer_setup(&b->fake_irq, intel_breadcrumbs_fake_irq, 0);
timer_setup(&b->hangcheck, intel_breadcrumbs_hangcheck, 0);
}
static void cancel_fake_irq(struct intel_engine_cs *engine)
{
struct intel_breadcrumbs *b = &engine->breadcrumbs;
del_timer_sync(&b->fake_irq); /* may queue b->hangcheck */
del_timer_sync(&b->hangcheck);
clear_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings);
}
void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine)
{
struct intel_breadcrumbs *b = &engine->breadcrumbs;
unsigned long flags;
spin_lock_irqsave(&b->irq_lock, flags);
/*
* Leave the fake_irq timer enabled (if it is running), but clear the
* bit so that it turns itself off on its next wake up and goes back
* to the long hangcheck interval if still required.
*/
clear_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings);
if (b->irq_enabled)
irq_enable(engine);
else
irq_disable(engine);
spin_unlock_irqrestore(&b->irq_lock, flags);
}
void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine)
{
cancel_fake_irq(engine);
}
bool i915_request_enable_breadcrumb(struct i915_request *rq)
{
struct intel_breadcrumbs *b = &rq->engine->breadcrumbs;
GEM_BUG_ON(test_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags));
if (!test_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags))
return true;
spin_lock(&b->irq_lock);
if (test_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags) &&
!__request_completed(rq)) {
struct intel_context *ce = rq->hw_context;
struct list_head *pos;
__intel_breadcrumbs_arm_irq(b);
/*
* We keep the seqno in retirement order, so we can break
* inside intel_engine_breadcrumbs_irq as soon as we've passed
* the last completed request (or seen a request that hasn't
* event started). We could iterate the timeline->requests list,
* but keeping a separate signalers_list has the advantage of
* hopefully being much smaller than the full list and so
* provides faster iteration and detection when there are no
* more interrupts required for this context.
*
* We typically expect to add new signalers in order, so we
* start looking for our insertion point from the tail of
* the list.
*/
list_for_each_prev(pos, &ce->signals) {
struct i915_request *it =
list_entry(pos, typeof(*it), signal_link);
if (i915_seqno_passed(rq->fence.seqno, it->fence.seqno))
break;
}
list_add(&rq->signal_link, pos);
if (pos == &ce->signals) /* catch transitions from empty list */
list_move_tail(&ce->signal_link, &b->signalers);
set_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags);
}
spin_unlock(&b->irq_lock);
return !__request_completed(rq);
}
void i915_request_cancel_breadcrumb(struct i915_request *rq)
{
struct intel_breadcrumbs *b = &rq->engine->breadcrumbs;
if (!test_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags))
return;
spin_lock(&b->irq_lock);
if (test_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags)) {
struct intel_context *ce = rq->hw_context;
list_del(&rq->signal_link);
if (list_empty(&ce->signals))
list_del_init(&ce->signal_link);
clear_bit(I915_FENCE_FLAG_SIGNAL, &rq->fence.flags);
}
spin_unlock(&b->irq_lock);
}
void intel_engine_print_breadcrumbs(struct intel_engine_cs *engine,
struct drm_printer *p)
{
struct intel_breadcrumbs *b = &engine->breadcrumbs;
struct intel_context *ce;
struct i915_request *rq;
if (list_empty(&b->signalers))
return;
drm_printf(p, "Signals:\n");
spin_lock_irq(&b->irq_lock);
list_for_each_entry(ce, &b->signalers, signal_link) {
list_for_each_entry(rq, &ce->signals, signal_link) {
drm_printf(p, "\t[%llx:%llx%s] @ %dms\n",
rq->fence.context, rq->fence.seqno,
i915_request_completed(rq) ? "!" :
i915_request_started(rq) ? "*" :
"",
jiffies_to_msecs(jiffies - rq->emitted_jiffies));
}
}
spin_unlock_irq(&b->irq_lock);
if (test_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings))
drm_printf(p, "Fake irq active\n");
}
|