| Message ID | 20200207085708.2711257-1-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm/i915/gt: Protect execlists_hold/unhold from new waiters | expand |
Chris Wilson <chris@chris-wilson.co.uk> writes: > As we may add new waiters to a request as it is being run, we need to > mark the list iteration as being safe for concurrent addition. > > v2: Mika spotted that we used the same trick for signalers_list, so warn > the compiler about the lockless walk there as well. > > Fixes: 32ff621fd744 ("drm/i915/gt: Allow temporary suspension of inflight requests") > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> > Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> > --- > drivers/gpu/drm/i915/gt/intel_lrc.c | 11 ++++++++--- > drivers/gpu/drm/i915/i915_scheduler.c | 2 +- > 2 files changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c > index b350e01d86d2..ed1e4d883d47 100644 > --- a/drivers/gpu/drm/i915/gt/intel_lrc.c > +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c > @@ -1620,6 +1620,11 @@ last_active(const struct intel_engine_execlists *execlists) > &(rq__)->sched.waiters_list, \ > wait_link) > > +#define for_each_signaler(p__, rq__) \ > + list_for_each_entry_lockless(p__, \ > + &(rq__)->sched.signalers_list, \ > + signal_link) > + > static void defer_request(struct i915_request *rq, struct list_head * const pl) > { > LIST_HEAD(list); > @@ -2378,7 +2383,7 @@ static void __execlists_hold(struct i915_request *rq) > list_move_tail(&rq->sched.link, &rq->engine->active.hold); > i915_request_set_hold(rq); > > - list_for_each_entry(p, &rq->sched.waiters_list, wait_link) { > + for_each_waiter(p, rq) { > struct i915_request *w = > container_of(p->waiter, typeof(*w), sched); > > @@ -2464,7 +2469,7 @@ static bool hold_request(const struct i915_request *rq) > * If one of our ancestors is on hold, we must also be on hold, > * otherwise we will bypass it and execute before it. > */ > - list_for_each_entry(p, &rq->sched.signalers_list, signal_link) { > + for_each_signaler(p, rq) { > const struct i915_request *s = > container_of(p->signaler, typeof(*s), sched); > > @@ -2496,7 +2501,7 @@ static void __execlists_unhold(struct i915_request *rq) > RQ_TRACE(rq, "hold release\n"); > > /* Also release any children on this engine that are ready */ > - list_for_each_entry(p, &rq->sched.waiters_list, wait_link) { > + for_each_waiter(p, rq) { > struct i915_request *w = > container_of(p->waiter, typeof(*w), sched); > > diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c > index 9cbd31443eb0..a9666df1d842 100644 > --- a/drivers/gpu/drm/i915/i915_scheduler.c > +++ b/drivers/gpu/drm/i915/i915_scheduler.c > @@ -432,7 +432,7 @@ bool __i915_sched_node_add_dependency(struct i915_sched_node *node, > !node_started(signal)) > node->flags |= I915_SCHED_HAS_SEMAPHORE_CHAIN; > > - list_add(&dep->signal_link, &node->signalers_list); > + list_add_rcu(&dep->signal_link, &node->signalers_list); > list_add_rcu(&dep->wait_link, &signal->waiters_list); > > /* > -- > 2.25.0
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index b350e01d86d2..ed1e4d883d47 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -1620,6 +1620,11 @@ last_active(const struct intel_engine_execlists *execlists) &(rq__)->sched.waiters_list, \ wait_link) +#define for_each_signaler(p__, rq__) \ + list_for_each_entry_lockless(p__, \ + &(rq__)->sched.signalers_list, \ + signal_link) + static void defer_request(struct i915_request *rq, struct list_head * const pl) { LIST_HEAD(list); @@ -2378,7 +2383,7 @@ static void __execlists_hold(struct i915_request *rq) list_move_tail(&rq->sched.link, &rq->engine->active.hold); i915_request_set_hold(rq); - list_for_each_entry(p, &rq->sched.waiters_list, wait_link) { + for_each_waiter(p, rq) { struct i915_request *w = container_of(p->waiter, typeof(*w), sched); @@ -2464,7 +2469,7 @@ static bool hold_request(const struct i915_request *rq) * If one of our ancestors is on hold, we must also be on hold, * otherwise we will bypass it and execute before it. */ - list_for_each_entry(p, &rq->sched.signalers_list, signal_link) { + for_each_signaler(p, rq) { const struct i915_request *s = container_of(p->signaler, typeof(*s), sched); @@ -2496,7 +2501,7 @@ static void __execlists_unhold(struct i915_request *rq) RQ_TRACE(rq, "hold release\n"); /* Also release any children on this engine that are ready */ - list_for_each_entry(p, &rq->sched.waiters_list, wait_link) { + for_each_waiter(p, rq) { struct i915_request *w = container_of(p->waiter, typeof(*w), sched); diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c index 9cbd31443eb0..a9666df1d842 100644 --- a/drivers/gpu/drm/i915/i915_scheduler.c +++ b/drivers/gpu/drm/i915/i915_scheduler.c @@ -432,7 +432,7 @@ bool __i915_sched_node_add_dependency(struct i915_sched_node *node, !node_started(signal)) node->flags |= I915_SCHED_HAS_SEMAPHORE_CHAIN; - list_add(&dep->signal_link, &node->signalers_list); + list_add_rcu(&dep->signal_link, &node->signalers_list); list_add_rcu(&dep->wait_link, &signal->waiters_list); /*
As we may add new waiters to a request as it is being run, we need to mark the list iteration as being safe for concurrent addition. v2: Mika spotted that we used the same trick for signalers_list, so warn the compiler about the lockless walk there as well. Fixes: 32ff621fd744 ("drm/i915/gt: Allow temporary suspension of inflight requests") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> --- drivers/gpu/drm/i915/gt/intel_lrc.c | 11 ++++++++--- drivers/gpu/drm/i915/i915_scheduler.c | 2 +- 2 files changed, 9 insertions(+), 4 deletions(-)