On Tue, Mar 20, 2018 at 12:18:46AM +0000, Chris Wilson wrote:
> In preparation to more carefully handling incomplete preemption during
> reset by execlists, we move the existing code wholesale to the backends
> under a couple of new reset vfuncs.
>
> Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
> Cc: Michał Winiarski <michal.winiar...@intel.com>
> CC: Michel Thierry <michel.thie...@intel.com>
> Cc: Jeff McGee <jeff.mc...@intel.com>
> ---
> drivers/gpu/drm/i915/i915_gem.c | 42 ++++----------------------
> drivers/gpu/drm/i915/intel_lrc.c | 52
> +++++++++++++++++++++++++++++++--
> drivers/gpu/drm/i915/intel_ringbuffer.c | 20 +++++++++++--
> drivers/gpu/drm/i915/intel_ringbuffer.h | 9 ++++--
> 4 files changed, 78 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 802df8e1a544..38f7160d99c9 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -2917,7 +2917,7 @@ static bool engine_stalled(struct intel_engine_cs
> *engine)
> struct i915_request *
> i915_gem_reset_prepare_engine(struct intel_engine_cs *engine)
> {
> - struct i915_request *request = NULL;
> + struct i915_request *request;
>
> /*
> * During the reset sequence, we must prevent the engine from
> @@ -2940,40 +2940,7 @@ i915_gem_reset_prepare_engine(struct intel_engine_cs
> *engine)
> */
> kthread_park(engine->breadcrumbs.signaler);
>
> - /*
> - * Prevent request submission to the hardware until we have
> - * completed the reset in i915_gem_reset_finish(). If a request
> - * is completed by one engine, it may then queue a request
> - * to a second via its execlists->tasklet *just* as we are
> - * calling engine->init_hw() and also writing the ELSP.
> - * Turning off the execlists->tasklet until the reset is over
> - * prevents the race.
> - *
> - * Note that this needs to be a single atomic operation on the
> - * tasklet (flush existing tasks, prevent new tasks) to prevent
> - * a race between reset and set-wedged. It is not, so we do the best
> - * we can atm and make sure we don't lock the machine up in the more
> - * common case of recursively being called from set-wedged from inside
> - * i915_reset.
> - */
> - if (!atomic_read(&engine->execlists.tasklet.count))
> - tasklet_kill(&engine->execlists.tasklet);
> - tasklet_disable(&engine->execlists.tasklet);
> -
> - /*
> - * We're using worker to queue preemption requests from the tasklet in
> - * GuC submission mode.
> - * Even though tasklet was disabled, we may still have a worker queued.
> - * Let's make sure that all workers scheduled before disabling the
> - * tasklet are completed before continuing with the reset.
> - */
> - if (engine->i915->guc.preempt_wq)
> - flush_workqueue(engine->i915->guc.preempt_wq);
> -
> - if (engine->irq_seqno_barrier)
> - engine->irq_seqno_barrier(engine);
> -
> - request = i915_gem_find_active_request(engine);
> + request = engine->reset.prepare(engine);
> if (request && request->fence.error == -EIO)
> request = ERR_PTR(-EIO); /* Previous reset failed! */
>
> @@ -3120,7 +3087,7 @@ void i915_gem_reset_engine(struct intel_engine_cs
> *engine,
> }
>
> /* Setup the CS to resume from the breadcrumb of the hung request */
> - engine->reset_hw(engine, request);
> + engine->reset.reset(engine, request);
> }
>
> void i915_gem_reset(struct drm_i915_private *dev_priv)
> @@ -3172,7 +3139,8 @@ void i915_gem_reset(struct drm_i915_private *dev_priv)
>
> void i915_gem_reset_finish_engine(struct intel_engine_cs *engine)
> {
> - tasklet_enable(&engine->execlists.tasklet);
> + engine->reset.finish(engine);
> +
> kthread_unpark(engine->breadcrumbs.signaler);
>
> intel_uncore_forcewake_put(engine->i915, FORCEWAKE_ALL);
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c
> b/drivers/gpu/drm/i915/intel_lrc.c
> index 0bfaeb56b8c7..f662a9524233 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -1663,6 +1663,44 @@ static int gen9_init_render_ring(struct
> intel_engine_cs *engine)
> return init_workarounds_ring(engine);
> }
>
> +static struct i915_request *
> +execlists_reset_prepare(struct intel_engine_cs *engine)
> +{
> + struct intel_engine_execlists * const execlists = &engine->execlists;
> +
> + /*
> + * Prevent request submission to the hardware until we have
> + * completed the reset in i915_gem_reset_finish(). If a request
> + * is completed by one engine, it may then queue a request
> + * to a second via its execlists->tasklet *just* as we are
> + * calling engine->init_hw() and also writing the ELSP.
> + * Turning off the execlists->tasklet until the reset is over
> + * prevents the race.
> + *
> + * Note that this needs to be a single atomic operation on the
> + * tasklet (flush existing tasks, prevent new tasks) to prevent
> + * a race between reset and set-wedged. It is not, so we do the best
> + * we can atm and make sure we don't lock the machine up in the more
> + * common case of recursively being called from set-wedged from inside
> + * i915_reset.
> + */
> + if (!atomic_read(&execlists->tasklet.count))
> + tasklet_kill(&execlists->tasklet);
> + tasklet_disable(&execlists->tasklet);
> +
> + /*
> + * We're using worker to queue preemption requests from the tasklet in
> + * GuC submission mode.
> + * Even though tasklet was disabled, we may still have a worker queued.
> + * Let's make sure that all workers scheduled before disabling the
> + * tasklet are completed before continuing with the reset.
> + */
> + if (engine->i915->guc.preempt_wq)
> + flush_workqueue(engine->i915->guc.preempt_wq);
> +
> + return i915_gem_find_active_request(engine);
> +}
> +
> static void reset_irq(struct intel_engine_cs *engine)
> {
> struct drm_i915_private *dev_priv = engine->i915;
> @@ -1692,8 +1730,8 @@ static void reset_irq(struct intel_engine_cs *engine)
> clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted);
> }
>
> -static void reset_common_ring(struct intel_engine_cs *engine,
> - struct i915_request *request)
> +static void execlists_reset(struct intel_engine_cs *engine,
> + struct i915_request *request)
> {
> struct intel_engine_execlists * const execlists = &engine->execlists;
> struct intel_context *ce;
> @@ -1766,6 +1804,11 @@ static void reset_common_ring(struct intel_engine_cs
> *engine,
> unwind_wa_tail(request);
> }
>
> +static void execlists_reset_finish(struct intel_engine_cs *engine)
> +{
> + tasklet_enable(&engine->execlists.tasklet);
> +}
> +
> static int intel_logical_ring_emit_pdps(struct i915_request *rq)
> {
> struct i915_hw_ppgtt *ppgtt = rq->ctx->ppgtt;
> @@ -2090,7 +2133,10 @@ logical_ring_default_vfuncs(struct intel_engine_cs
> *engine)
> {
> /* Default vfuncs which can be overriden by each engine. */
> engine->init_hw = gen8_init_common_ring;
> - engine->reset_hw = reset_common_ring;
> +
> + engine->reset.prepare = execlists_reset_prepare;
> + engine->reset.reset = execlists_reset;
> + engine->reset.finish = execlists_reset_finish;
>
> engine->context_pin = execlists_context_pin;
> engine->context_unpin = execlists_context_unpin;
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c
> b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index 04d9d9a946a7..eebcc877ef60 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -530,8 +530,16 @@ static int init_ring_common(struct intel_engine_cs
> *engine)
> return ret;
> }
>
> -static void reset_ring_common(struct intel_engine_cs *engine,
> - struct i915_request *request)
> +static struct i915_request *reset_prepare(struct intel_engine_cs *engine)
> +{
> + if (engine->irq_seqno_barrier)
> + engine->irq_seqno_barrier(engine);
> +
> + return i915_gem_find_active_request(engine);
> +}
> +
> +static void reset_ring(struct intel_engine_cs *engine,
> + struct i915_request *request)
> {
> /*
> * RC6 must be prevented until the reset is complete and the engine
> @@ -595,6 +603,10 @@ static void reset_ring_common(struct intel_engine_cs
> *engine,
> }
> }
>
> +static void reset_finish(struct intel_engine_cs *engine)
> +{
> +}
> +
> static int intel_rcs_ctx_init(struct i915_request *rq)
> {
> int ret;
> @@ -1987,7 +1999,9 @@ static void intel_ring_default_vfuncs(struct
> drm_i915_private *dev_priv,
> intel_ring_init_semaphores(dev_priv, engine);
>
> engine->init_hw = init_ring_common;
> - engine->reset_hw = reset_ring_common;
> + engine->reset.prepare = reset_prepare;
> + engine->reset.reset = reset_ring;
> + engine->reset.finish = reset_finish;
>
> engine->context_pin = intel_ring_context_pin;
> engine->context_unpin = intel_ring_context_unpin;
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h
> b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index 1f50727a5ddb..e2681303ce21 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -418,8 +418,13 @@ struct intel_engine_cs {
> void (*irq_disable)(struct intel_engine_cs *engine);
>
> int (*init_hw)(struct intel_engine_cs *engine);
> - void (*reset_hw)(struct intel_engine_cs *engine,
> - struct i915_request *rq);
> +
> + struct {
> + struct i915_request *(*prepare)(struct intel_engine_cs *engine);
> + void (*reset)(struct intel_engine_cs *engine,
> + struct i915_request *rq);
> + void (*finish)(struct intel_engine_cs *engine);
> + } reset;
>
> void (*park)(struct intel_engine_cs *engine);
> void (*unpark)(struct intel_engine_cs *engine);
> --
> 2.16.2
>
Reviewed-by: Jeff McGee <jeff.mc...@intel.com>
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