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[1/4] drm/i915/execlists: Pull tasklet interrupt-bh local to direct submission

Message ID 20200323130935.13568-1-chris@chris-wilson.co.uk (mailing list archive)
State New, archived
Headers show
Series [1/4] drm/i915/execlists: Pull tasklet interrupt-bh local to direct submission | expand

Commit Message

Chris Wilson March 23, 2020, 1:09 p.m. UTC
We dropped calling process_csb prior to handling direct submission in
order to avoid the nesting of spinlocks and lift process_csb() and the
majority of the tasklet out of irq-off. However, we do want to avoid
ksoftirqd latency in the fast path, so try and pull the interrupt-bh
local to direct submission if we can acquire the tasklet's lock.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c | 6 ++++++
 1 file changed, 6 insertions(+)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 210f60e14ef4..82dee2141b46 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -2891,6 +2891,12 @@  static void __submit_queue_imm(struct intel_engine_cs *engine)
 	if (reset_in_progress(execlists))
 		return; /* defer until we restart the engine following reset */
 
+	/* Hopefully we clear execlists->pending[] to let us through */
+	if (execlists->pending[0] && tasklet_trylock(&execlists->tasklet)) {
+		process_csb(engine);
+		tasklet_unlock(&execlists->tasklet);
+	}
+
 	__execlists_submission_tasklet(engine);
 }