From 2b2985a417c7ca1752a4f0b2631cf916dabd43b5 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 8 Jan 2021 20:40:23 +0000 Subject: [PATCH] drm/i915/gt: Restore ce->signal flush before releasing virtual engine Before we mark the virtual engine as no longer inflight, flush any ongoing signaling that may be using the ce->signal_link along the previous breadcrumbs. On switch to a new physical engine, that link will be inserted into the new set of breadcrumbs, causing confusion to an ongoing iterator. This patch undoes a last minute mistake introduced into commit bab0557c8dca ("drm/i915/gt: Remove virtual breadcrumb before transfer"), whereby instead of unconditionally applying the flush, it was only applied if the request itself was going to be reused. v2: Generalise and cancel all remaining ce->signals Fixes: bab0557c8dca ("drm/i915/gt: Remove virtual breadcrumb before transfer") Signed-off-by: Chris Wilson Reviewed-by: Andi Shyti Link: https://patchwork.freedesktop.org/patch/msgid/20210108204026.20682-4-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 33 ++++++++++++++++++++++ drivers/gpu/drm/i915/gt/intel_breadcrumbs.h | 4 +++ .../gpu/drm/i915/gt/intel_execlists_submission.c | 25 +++++++--------- 3 files changed, 47 insertions(+), 15 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c index 2eabb9a..7137b6f 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c @@ -472,6 +472,39 @@ void i915_request_cancel_breadcrumb(struct i915_request *rq) i915_request_put(rq); } +void intel_context_remove_breadcrumbs(struct intel_context *ce, + struct intel_breadcrumbs *b) +{ + struct i915_request *rq, *rn; + bool release = false; + unsigned long flags; + + spin_lock_irqsave(&ce->signal_lock, flags); + + if (list_empty(&ce->signals)) + goto unlock; + + list_for_each_entry_safe(rq, rn, &ce->signals, signal_link) { + GEM_BUG_ON(!__i915_request_is_complete(rq)); + if (!test_and_clear_bit(I915_FENCE_FLAG_SIGNAL, + &rq->fence.flags)) + continue; + + list_del_rcu(&rq->signal_link); + irq_signal_request(rq, b); + i915_request_put(rq); + } + release = remove_signaling_context(b, ce); + +unlock: + spin_unlock_irqrestore(&ce->signal_lock, flags); + if (release) + intel_context_put(ce); + + while (atomic_read(&b->signaler_active)) + cpu_relax(); +} + static void print_signals(struct intel_breadcrumbs *b, struct drm_printer *p) { struct intel_context *ce; diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h index 75cc9cf..3ce5ce2 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h @@ -6,6 +6,7 @@ #ifndef __INTEL_BREADCRUMBS__ #define __INTEL_BREADCRUMBS__ +#include #include #include "intel_engine_types.h" @@ -44,4 +45,7 @@ void intel_engine_print_breadcrumbs(struct intel_engine_cs *engine, bool i915_request_enable_breadcrumb(struct i915_request *request); void i915_request_cancel_breadcrumb(struct i915_request *request); +void intel_context_remove_breadcrumbs(struct intel_context *ce, + struct intel_breadcrumbs *b); + #endif /* __INTEL_BREADCRUMBS__ */ diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c index 2f8e104..eb69eef 100644 --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c @@ -581,21 +581,6 @@ resubmit_virtual_request(struct i915_request *rq, struct virtual_engine *ve) { struct intel_engine_cs *engine = rq->engine; - /* Flush concurrent rcu iterators in signal_irq_work */ - if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &rq->fence.flags)) { - /* - * After this point, the rq may be transferred to a new - * sibling, so before we clear ce->inflight make sure that - * the context has been removed from the b->signalers and - * furthermore we need to make sure that the concurrent - * iterator in signal_irq_work is no longer following - * ce->signal_link. - */ - i915_request_cancel_breadcrumb(rq); - while (atomic_read(&engine->breadcrumbs->signaler_active)) - cpu_relax(); - } - spin_lock_irq(&engine->active.lock); clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags); @@ -611,6 +596,16 @@ static void kick_siblings(struct i915_request *rq, struct intel_context *ce) struct intel_engine_cs *engine = rq->engine; /* + * After this point, the rq may be transferred to a new sibling, so + * before we clear ce->inflight make sure that the context has been + * removed from the b->signalers and furthermore we need to make sure + * that the concurrent iterator in signal_irq_work is no longer + * following ce->signal_link. + */ + if (!list_empty(&ce->signals)) + intel_context_remove_breadcrumbs(ce, engine->breadcrumbs); + + /* * This engine is now too busy to run this virtual request, so * see if we can find an alternative engine for it to execute on. * Once a request has become bonded to this engine, we treat it the -- 2.7.4