From 71ace7ca2545d7cd7522988c16ad6c94e6169366 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 7 May 2018 14:57:26 +0100 Subject: [PATCH] drm/i915: Disable tasklet scheduling across initial scheduling During request submission, we call the engine->schedule() function so that we may reorder the active requests as required for inheriting the new request's priority. This may schedule several tasklets to run on the local CPU, but we will need to schedule the tasklets again for the new request. Delay all the local tasklets until the end, so that we only have to process the queue just once. v2: Beware PREEMPT_RCU, as then local_bh_disable() is then not a superset of rcu_read_lock(). Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20180507135731.10587-2-chris@chris-wilson.co.uk Reviewed-by: Tvrtko Ursulin --- drivers/gpu/drm/i915/i915_request.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index e4cf76ec14a6..f336942229cf 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -1110,12 +1110,11 @@ void __i915_request_add(struct i915_request *request, bool flush_caches) * decide whether to preempt the entire chain so that it is ready to * run at the earliest possible convenience. */ - rcu_read_lock(); + local_bh_disable(); + rcu_read_lock(); /* RCU serialisation for set-wedged protection */ if (engine->schedule) engine->schedule(request, &request->ctx->sched); rcu_read_unlock(); - - local_bh_disable(); i915_sw_fence_commit(&request->submit); local_bh_enable(); /* Kick the execlists tasklet if just scheduled */ -- 2.17.1