Quoting Mika Kuoppala (2020-01-29 09:29:43) > Chris Wilson <[email protected]> writes: > > > We write to execlists->pending[0] in process_csb() to acknowledge the > > completion of the ESLP update, outside of the main spinlock. When we > > check the current status of the previous submission in > > __execlists_submission_tasklet() we should therefore use READ_ONCE() to > > reflect and document the unsynchronized read. > > > > Signed-off-by: Chris Wilson <[email protected]> > > Cc: Tvrtko Ursulin <[email protected]> > > --- > > drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c > > b/drivers/gpu/drm/i915/gt/intel_lrc.c > > index cf6c43bd540a..058484958e87 100644 > > --- a/drivers/gpu/drm/i915/gt/intel_lrc.c > > +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c > > @@ -2347,7 +2347,7 @@ static void process_csb(struct intel_engine_cs > > *engine) > > static void __execlists_submission_tasklet(struct intel_engine_cs *const > > engine) > > { > > lockdep_assert_held(&engine->active.lock); > > - if (!engine->execlists.pending[0]) { > > + if (!READ_ONCE(engine->execlists.pending[0])) { > > With same token, should we also include assert_pending_invalid() > read of pending with READ_ONCE?
That happens on the control paths, so the state of pending[] at that point should be static (and the compiler can be left to its own devices). -Chris _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
