From b8e2bd98a2c9c3a90856c1909aab30d25d379c31 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 26 Nov 2020 14:04:03 +0000 Subject: [PATCH] drm/i915/gt: Decouple completed requests on unwind Since the introduction of preempt-to-busy, requests can complete in the background, even while they are not on the engine->active.requests list. As such, the engine->active.request list itself is not in strict retirement order, and we have to scan the entire list while unwinding to not miss any. However, if the request is completed we currently leave it on the list [until retirement], but we could just as simply remove it and stop treating it as active. We would only have to then traverse it once while unwinding in quick succession. Signed-off-by: Chris Wilson Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20201126140407.31952-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/gt/intel_lrc.c | 6 ++++-- drivers/gpu/drm/i915/i915_request.c | 3 ++- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 30aa59fb72713..cf11cbac241bb 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -1116,8 +1116,10 @@ __unwind_incomplete_requests(struct intel_engine_cs *engine) list_for_each_entry_safe_reverse(rq, rn, &engine->active.requests, sched.link) { - if (i915_request_completed(rq)) - continue; /* XXX */ + if (i915_request_completed(rq)) { + list_del_init(&rq->sched.link); + continue; + } __i915_request_unsubmit(rq); diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index 8d7d29c9e375d..a9db1376b996c 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -321,7 +321,8 @@ bool i915_request_retire(struct i915_request *rq) * after removing the breadcrumb and signaling it, so that we do not * inadvertently attach the breadcrumb to a completed request. */ - remove_from_engine(rq); + if (!list_empty(&rq->sched.link)) + remove_from_engine(rq); GEM_BUG_ON(!llist_empty(&rq->execute_cb)); __list_del_entry(&rq->link); /* poison neither prev/next (RCU walks) */ -- 2.39.5