[Intel-gfx] [PATCH 24/33] drm/i915/guc: Implement banned contexts for GuC submission
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Wed Aug 25 10:39:10 UTC 2021
On 27/07/2021 01:23, Matthew Brost wrote:
> When using GuC submission, if a context gets banned disable scheduling
> and mark all inflight requests as complete.
>
> Cc: John Harrison <John.C.Harrison at Intel.com>
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> Reviewed-by: John Harrison <John.C.Harrison at Intel.com>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_context.c | 2 +-
> drivers/gpu/drm/i915/gt/intel_context.h | 13 ++
> drivers/gpu/drm/i915/gt/intel_context_types.h | 2 +
> drivers/gpu/drm/i915/gt/intel_reset.c | 32 +---
> .../gpu/drm/i915/gt/intel_ring_submission.c | 20 +++
> drivers/gpu/drm/i915/gt/uc/intel_guc.h | 2 +
> .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 151 ++++++++++++++++--
> drivers/gpu/drm/i915/i915_trace.h | 10 ++
> 8 files changed, 195 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index e3df01a201d7..05c3ee191710 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -1084,7 +1084,7 @@ static void kill_engines(struct i915_gem_engines *engines, bool ban)
> for_each_gem_engine(ce, engines, it) {
> struct intel_engine_cs *engine;
>
> - if (ban && intel_context_set_banned(ce))
> + if (ban && intel_context_ban(ce, NULL))
> continue;
>
> /*
> diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h
> index 2ed9bf5f91a5..814d9277096a 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context.h
> +++ b/drivers/gpu/drm/i915/gt/intel_context.h
> @@ -16,6 +16,7 @@
> #include "intel_engine_types.h"
> #include "intel_ring_types.h"
> #include "intel_timeline_types.h"
> +#include "i915_trace.h"
>
> #define CE_TRACE(ce, fmt, ...) do { \
> const struct intel_context *ce__ = (ce); \
> @@ -243,6 +244,18 @@ static inline bool intel_context_set_banned(struct intel_context *ce)
> return test_and_set_bit(CONTEXT_BANNED, &ce->flags);
> }
>
> +static inline bool intel_context_ban(struct intel_context *ce,
> + struct i915_request *rq)
> +{
> + bool ret = intel_context_set_banned(ce);
> +
> + trace_intel_context_ban(ce);
> + if (ce->ops->ban)
> + ce->ops->ban(ce, rq);
> +
> + return ret;
> +}
> +
> static inline bool
> intel_context_force_single_submission(const struct intel_context *ce)
> {
> diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
> index 035108c10b2c..57c19ee3e313 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
> @@ -35,6 +35,8 @@ struct intel_context_ops {
>
> int (*alloc)(struct intel_context *ce);
>
> + void (*ban)(struct intel_context *ce, struct i915_request *rq);
> +
> int (*pre_pin)(struct intel_context *ce, struct i915_gem_ww_ctx *ww, void **vaddr);
> int (*pin)(struct intel_context *ce, void *vaddr);
> void (*unpin)(struct intel_context *ce);
> diff --git a/drivers/gpu/drm/i915/gt/intel_reset.c b/drivers/gpu/drm/i915/gt/intel_reset.c
> index 4d281bc8a38c..91200c43951f 100644
> --- a/drivers/gpu/drm/i915/gt/intel_reset.c
> +++ b/drivers/gpu/drm/i915/gt/intel_reset.c
> @@ -22,7 +22,6 @@
> #include "intel_reset.h"
>
> #include "uc/intel_guc.h"
> -#include "uc/intel_guc_submission.h"
>
> #define RESET_MAX_RETRIES 3
>
> @@ -39,21 +38,6 @@ static void rmw_clear_fw(struct intel_uncore *uncore, i915_reg_t reg, u32 clr)
> intel_uncore_rmw_fw(uncore, reg, clr, 0);
> }
>
> -static void skip_context(struct i915_request *rq)
> -{
> - struct intel_context *hung_ctx = rq->context;
> -
> - list_for_each_entry_from_rcu(rq, &hung_ctx->timeline->requests, link) {
> - if (!i915_request_is_active(rq))
> - return;
> -
> - if (rq->context == hung_ctx) {
> - i915_request_set_error_once(rq, -EIO);
> - __i915_request_skip(rq);
> - }
> - }
> -}
> -
> static void client_mark_guilty(struct i915_gem_context *ctx, bool banned)
> {
> struct drm_i915_file_private *file_priv = ctx->file_priv;
> @@ -88,10 +72,8 @@ static bool mark_guilty(struct i915_request *rq)
> bool banned;
> int i;
>
> - if (intel_context_is_closed(rq->context)) {
> - intel_context_set_banned(rq->context);
> + if (intel_context_is_closed(rq->context))
> return true;
> - }
>
> rcu_read_lock();
> ctx = rcu_dereference(rq->context->gem_context);
> @@ -123,11 +105,9 @@ static bool mark_guilty(struct i915_request *rq)
> banned = !i915_gem_context_is_recoverable(ctx);
> if (time_before(jiffies, prev_hang + CONTEXT_FAST_HANG_JIFFIES))
> banned = true;
> - if (banned) {
> + if (banned)
> drm_dbg(&ctx->i915->drm, "context %s: guilty %d, banned\n",
> ctx->name, atomic_read(&ctx->guilty_count));
> - intel_context_set_banned(rq->context);
> - }
>
> client_mark_guilty(ctx, banned);
>
> @@ -149,6 +129,8 @@ static void mark_innocent(struct i915_request *rq)
>
> void __i915_request_reset(struct i915_request *rq, bool guilty)
> {
> + bool banned = false;
> +
> RQ_TRACE(rq, "guilty? %s\n", yesno(guilty));
> GEM_BUG_ON(__i915_request_is_complete(rq));
>
> @@ -156,13 +138,15 @@ void __i915_request_reset(struct i915_request *rq, bool guilty)
> if (guilty) {
> i915_request_set_error_once(rq, -EIO);
> __i915_request_skip(rq);
> - if (mark_guilty(rq) && !intel_engine_uses_guc(rq->engine))
> - skip_context(rq);
> + banned = mark_guilty(rq);
> } else {
> i915_request_set_error_once(rq, -EAGAIN);
> mark_innocent(rq);
> }
> rcu_read_unlock();
> +
> + if (banned)
> + intel_context_ban(rq->context, rq);
> }
>
> static bool i915_in_reset(struct pci_dev *pdev)
> diff --git a/drivers/gpu/drm/i915/gt/intel_ring_submission.c b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> index a5404c7b600f..05bb9f449df1 100644
> --- a/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> @@ -586,9 +586,29 @@ static void ring_context_reset(struct intel_context *ce)
> clear_bit(CONTEXT_VALID_BIT, &ce->flags);
> }
>
> +static void ring_context_ban(struct intel_context *ce,
> + struct i915_request *rq)
> +{
> + struct intel_engine_cs *engine;
> +
> + if (!rq || !i915_request_is_active(rq))
> + return;
When this gets called from context close, via intel_context_ban, rq will
be always NULL - so the below loop which skips a line of executing
requests never gets to run.
This appears a functional change versus previous state of the codebase,
where skip_context() would run in any case.
I had this observation from a patch I am working on
(https://intel-gfx-ci.01.org/tree/drm-tip/Trybot_7950/shard-snb6/igt@gem_ctx_exec@basic-nohangcheck.html
- so a long line of executing requests which did not get zapped post
reset), but may be wrong. Maybe I am missing something since I don't yet
understand why would I be first to hit this issue. So take it with a
grain of salt for now.
Ah.. maybe the key is that in my patch I made intel_context_ban not call
ce->ops->"ban" (I renamed it to revoke) unconditionally. Hence there may
be a path there intel_context_ban is first called wo/ a rq, then from
within __i915_request_reset it gets called with rq, which now fails to
call the vfunc. Hm that's clunky and fragile which ever way I look at
it. I'll trybot one more experiment..
Regards,
Tvrtko
> +
> + engine = rq->engine;
> + lockdep_assert_held(&engine->sched_engine->lock);
> + list_for_each_entry_continue(rq, &engine->sched_engine->requests,
> + sched.link)
> + if (rq->context == ce) {
> + i915_request_set_error_once(rq, -EIO);
> + __i915_request_skip(rq);
> + }
> +}
> +
> static const struct intel_context_ops ring_context_ops = {
> .alloc = ring_context_alloc,
>
> + .ban = ring_context_ban,
> +
> .pre_pin = ring_context_pre_pin,
> .pin = ring_context_pin,
> .unpin = ring_context_unpin,
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> index 1875303c3bca..8ab70a2223b0 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> @@ -281,6 +281,8 @@ void intel_guc_find_hung_context(struct intel_engine_cs *engine);
>
> int intel_guc_global_policies_update(struct intel_guc *guc);
>
> +void intel_guc_context_ban(struct intel_context *ce, struct i915_request *rq);
> +
> void intel_guc_submission_reset_prepare(struct intel_guc *guc);
> void intel_guc_submission_reset(struct intel_guc *guc, bool stalled);
> void intel_guc_submission_reset_finish(struct intel_guc *guc);
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> index cea3e3073a71..ad9a38a861df 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -125,6 +125,7 @@ static inline void clr_context_pending_enable(struct intel_context *ce)
> #define SCHED_STATE_WAIT_FOR_DEREGISTER_TO_REGISTER BIT(0)
> #define SCHED_STATE_DESTROYED BIT(1)
> #define SCHED_STATE_PENDING_DISABLE BIT(2)
> +#define SCHED_STATE_BANNED BIT(3)
> static inline void init_sched_state(struct intel_context *ce)
> {
> /* Only should be called from guc_lrc_desc_pin() */
> @@ -185,6 +186,23 @@ static inline void clr_context_pending_disable(struct intel_context *ce)
> ce->guc_state.sched_state &= ~SCHED_STATE_PENDING_DISABLE;
> }
>
> +static inline bool context_banned(struct intel_context *ce)
> +{
> + return ce->guc_state.sched_state & SCHED_STATE_BANNED;
> +}
> +
> +static inline void set_context_banned(struct intel_context *ce)
> +{
> + lockdep_assert_held(&ce->guc_state.lock);
> + ce->guc_state.sched_state |= SCHED_STATE_BANNED;
> +}
> +
> +static inline void clr_context_banned(struct intel_context *ce)
> +{
> + lockdep_assert_held(&ce->guc_state.lock);
> + ce->guc_state.sched_state &= ~SCHED_STATE_BANNED;
> +}
> +
> static inline bool context_guc_id_invalid(struct intel_context *ce)
> {
> return ce->guc_id == GUC_INVALID_LRC_ID;
> @@ -357,13 +375,23 @@ static int guc_lrc_desc_pin(struct intel_context *ce, bool loop);
>
> static int guc_add_request(struct intel_guc *guc, struct i915_request *rq)
> {
> - int err;
> + int err = 0;
> struct intel_context *ce = rq->context;
> u32 action[3];
> int len = 0;
> u32 g2h_len_dw = 0;
> bool enabled;
>
> + /*
> + * Corner case where requests were sitting in the priority list or a
> + * request resubmitted after the context was banned.
> + */
> + if (unlikely(intel_context_is_banned(ce))) {
> + i915_request_put(i915_request_mark_eio(rq));
> + intel_engine_signal_breadcrumbs(ce->engine);
> + goto out;
> + }
> +
> GEM_BUG_ON(!atomic_read(&ce->guc_id_ref));
> GEM_BUG_ON(context_guc_id_invalid(ce));
>
> @@ -399,6 +427,8 @@ static int guc_add_request(struct intel_guc *guc, struct i915_request *rq)
> clr_context_pending_enable(ce);
> intel_context_put(ce);
> }
> + if (likely(!err))
> + trace_i915_request_guc_submit(rq);
>
> out:
> return err;
> @@ -463,7 +493,6 @@ static int guc_dequeue_one_context(struct intel_guc *guc)
> guc->stalled_request = last;
> return false;
> }
> - trace_i915_request_guc_submit(last);
> }
>
> guc->stalled_request = NULL;
> @@ -502,12 +531,13 @@ static void cs_irq_handler(struct intel_engine_cs *engine, u16 iir)
> static void __guc_context_destroy(struct intel_context *ce);
> static void release_guc_id(struct intel_guc *guc, struct intel_context *ce);
> static void guc_signal_context_fence(struct intel_context *ce);
> +static void guc_cancel_context_requests(struct intel_context *ce);
>
> static void scrub_guc_desc_for_outstanding_g2h(struct intel_guc *guc)
> {
> struct intel_context *ce;
> unsigned long index, flags;
> - bool pending_disable, pending_enable, deregister, destroyed;
> + bool pending_disable, pending_enable, deregister, destroyed, banned;
>
> xa_for_each(&guc->context_lookup, index, ce) {
> /* Flush context */
> @@ -525,6 +555,7 @@ static void scrub_guc_desc_for_outstanding_g2h(struct intel_guc *guc)
> pending_enable = context_pending_enable(ce);
> pending_disable = context_pending_disable(ce);
> deregister = context_wait_for_deregister_to_register(ce);
> + banned = context_banned(ce);
> init_sched_state(ce);
>
> if (pending_enable || destroyed || deregister) {
> @@ -542,6 +573,10 @@ static void scrub_guc_desc_for_outstanding_g2h(struct intel_guc *guc)
> /* Not mutualy exclusive with above if statement. */
> if (pending_disable) {
> guc_signal_context_fence(ce);
> + if (banned) {
> + guc_cancel_context_requests(ce);
> + intel_engine_signal_breadcrumbs(ce->engine);
> + }
> intel_context_sched_disable_unpin(ce);
> atomic_dec(&guc->outstanding_submission_g2h);
> intel_context_put(ce);
> @@ -661,6 +696,9 @@ static void guc_reset_state(struct intel_context *ce, u32 head, bool scrub)
> {
> struct intel_engine_cs *engine = __context_to_physical_engine(ce);
>
> + if (intel_context_is_banned(ce))
> + return;
> +
> GEM_BUG_ON(!intel_context_is_pinned(ce));
>
> /*
> @@ -731,6 +769,8 @@ static void __guc_reset_context(struct intel_context *ce, bool stalled)
> struct i915_request *rq;
> u32 head;
>
> + intel_context_get(ce);
> +
> /*
> * GuC will implicitly mark the context as non-schedulable
> * when it sends the reset notification. Make sure our state
> @@ -756,6 +796,7 @@ static void __guc_reset_context(struct intel_context *ce, bool stalled)
> out_replay:
> guc_reset_state(ce, head, stalled);
> __unwind_incomplete_requests(ce);
> + intel_context_put(ce);
> }
>
> void intel_guc_submission_reset(struct intel_guc *guc, bool stalled)
> @@ -940,8 +981,6 @@ static int guc_bypass_tasklet_submit(struct intel_guc *guc,
> ret = guc_add_request(guc, rq);
> if (ret == -EBUSY)
> guc->stalled_request = rq;
> - else
> - trace_i915_request_guc_submit(rq);
>
> if (unlikely(ret == -EPIPE))
> disable_submission(guc);
> @@ -1344,13 +1383,77 @@ static u16 prep_context_pending_disable(struct intel_context *ce)
> return ce->guc_id;
> }
>
> +static void __guc_context_set_preemption_timeout(struct intel_guc *guc,
> + u16 guc_id,
> + u32 preemption_timeout)
> +{
> + u32 action[] = {
> + INTEL_GUC_ACTION_SET_CONTEXT_PREEMPTION_TIMEOUT,
> + guc_id,
> + preemption_timeout
> + };
> +
> + intel_guc_send_busy_loop(guc, action, ARRAY_SIZE(action), 0, true);
> +}
> +
> +static void guc_context_ban(struct intel_context *ce, struct i915_request *rq)
> +{
> + struct intel_guc *guc = ce_to_guc(ce);
> + struct intel_runtime_pm *runtime_pm =
> + &ce->engine->gt->i915->runtime_pm;
> + intel_wakeref_t wakeref;
> + unsigned long flags;
> +
> + guc_flush_submissions(guc);
> +
> + spin_lock_irqsave(&ce->guc_state.lock, flags);
> + set_context_banned(ce);
> +
> + if (submission_disabled(guc) ||
> + (!context_enabled(ce) && !context_pending_disable(ce))) {
> + spin_unlock_irqrestore(&ce->guc_state.lock, flags);
> +
> + guc_cancel_context_requests(ce);
> + intel_engine_signal_breadcrumbs(ce->engine);
> + } else if (!context_pending_disable(ce)) {
> + u16 guc_id;
> +
> + /*
> + * We add +2 here as the schedule disable complete CTB handler
> + * calls intel_context_sched_disable_unpin (-2 to pin_count).
> + */
> + atomic_add(2, &ce->pin_count);
> +
> + guc_id = prep_context_pending_disable(ce);
> + spin_unlock_irqrestore(&ce->guc_state.lock, flags);
> +
> + /*
> + * In addition to disabling scheduling, set the preemption
> + * timeout to the minimum value (1 us) so the banned context
> + * gets kicked off the HW ASAP.
> + */
> + with_intel_runtime_pm(runtime_pm, wakeref) {
> + __guc_context_set_preemption_timeout(guc, guc_id, 1);
> + __guc_context_sched_disable(guc, ce, guc_id);
> + }
> + } else {
> + if (!context_guc_id_invalid(ce))
> + with_intel_runtime_pm(runtime_pm, wakeref)
> + __guc_context_set_preemption_timeout(guc,
> + ce->guc_id,
> + 1);
> + spin_unlock_irqrestore(&ce->guc_state.lock, flags);
> + }
> +}
> +
> static void guc_context_sched_disable(struct intel_context *ce)
> {
> struct intel_guc *guc = ce_to_guc(ce);
> - struct intel_runtime_pm *runtime_pm = &ce->engine->gt->i915->runtime_pm;
> unsigned long flags;
> - u16 guc_id;
> + struct intel_runtime_pm *runtime_pm = &ce->engine->gt->i915->runtime_pm;
> intel_wakeref_t wakeref;
> + u16 guc_id;
> + bool enabled;
>
> if (submission_disabled(guc) || context_guc_id_invalid(ce) ||
> !lrc_desc_registered(guc, ce->guc_id)) {
> @@ -1364,14 +1467,22 @@ static void guc_context_sched_disable(struct intel_context *ce)
> spin_lock_irqsave(&ce->guc_state.lock, flags);
>
> /*
> - * We have to check if the context has been pinned again as another pin
> - * operation is allowed to pass this function. Checking the pin count,
> - * within ce->guc_state.lock, synchronizes this function with
> + * We have to check if the context has been disabled by another thread.
> + * We also have to check if the context has been pinned again as another
> + * pin operation is allowed to pass this function. Checking the pin
> + * count, within ce->guc_state.lock, synchronizes this function with
> * guc_request_alloc ensuring a request doesn't slip through the
> * 'context_pending_disable' fence. Checking within the spin lock (can't
> * sleep) ensures another process doesn't pin this context and generate
> * a request before we set the 'context_pending_disable' flag here.
> */
> + enabled = context_enabled(ce);
> + if (unlikely(!enabled || submission_disabled(guc))) {
> + if (enabled)
> + clr_context_enabled(ce);
> + spin_unlock_irqrestore(&ce->guc_state.lock, flags);
> + goto unpin;
> + }
> if (unlikely(atomic_add_unless(&ce->pin_count, -2, 2))) {
> spin_unlock_irqrestore(&ce->guc_state.lock, flags);
> return;
> @@ -1529,6 +1640,8 @@ static const struct intel_context_ops guc_context_ops = {
> .unpin = guc_context_unpin,
> .post_unpin = guc_context_post_unpin,
>
> + .ban = guc_context_ban,
> +
> .enter = intel_context_enter_engine,
> .exit = intel_context_exit_engine,
>
> @@ -1722,6 +1835,8 @@ static const struct intel_context_ops virtual_guc_context_ops = {
> .unpin = guc_context_unpin,
> .post_unpin = guc_context_post_unpin,
>
> + .ban = guc_context_ban,
> +
> .enter = guc_virtual_context_enter,
> .exit = guc_virtual_context_exit,
>
> @@ -2164,6 +2279,8 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,
> if (context_pending_enable(ce)) {
> clr_context_pending_enable(ce);
> } else if (context_pending_disable(ce)) {
> + bool banned;
> +
> /*
> * Unpin must be done before __guc_signal_context_fence,
> * otherwise a race exists between the requests getting
> @@ -2174,9 +2291,16 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,
> intel_context_sched_disable_unpin(ce);
>
> spin_lock_irqsave(&ce->guc_state.lock, flags);
> + banned = context_banned(ce);
> + clr_context_banned(ce);
> clr_context_pending_disable(ce);
> __guc_signal_context_fence(ce);
> spin_unlock_irqrestore(&ce->guc_state.lock, flags);
> +
> + if (banned) {
> + guc_cancel_context_requests(ce);
> + intel_engine_signal_breadcrumbs(ce->engine);
> + }
> }
>
> decr_outstanding_submission_g2h(guc);
> @@ -2211,8 +2335,11 @@ static void guc_handle_context_reset(struct intel_guc *guc,
> struct intel_context *ce)
> {
> trace_intel_context_reset(ce);
> - capture_error_state(guc, ce);
> - guc_context_replay(ce);
> +
> + if (likely(!intel_context_is_banned(ce))) {
> + capture_error_state(guc, ce);
> + guc_context_replay(ce);
> + }
> }
>
> int intel_guc_context_reset_process_msg(struct intel_guc *guc,
> diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
> index 3f43d904f043..9613a7c19661 100644
> --- a/drivers/gpu/drm/i915/i915_trace.h
> +++ b/drivers/gpu/drm/i915/i915_trace.h
> @@ -925,6 +925,11 @@ DEFINE_EVENT(intel_context, intel_context_reset,
> TP_ARGS(ce)
> );
>
> +DEFINE_EVENT(intel_context, intel_context_ban,
> + TP_PROTO(struct intel_context *ce),
> + TP_ARGS(ce)
> +);
> +
> DEFINE_EVENT(intel_context, intel_context_register,
> TP_PROTO(struct intel_context *ce),
> TP_ARGS(ce)
> @@ -1017,6 +1022,11 @@ trace_intel_context_reset(struct intel_context *ce)
> {
> }
>
> +static inline void
> +trace_intel_context_ban(struct intel_context *ce)
> +{
> +}
> +
> static inline void
> trace_intel_context_register(struct intel_context *ce)
> {
>
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