The blocking gather copy allocation is a major performance downside of the
Host1x firewall, it may take hundreds milliseconds which is unacceptable
for the real-time graphics operations. Let's try a non-blocking allocation
first as a least invasive solution, it makes opentegra (Xorg driver)
performance indistinguishable with/without the firewall.
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
Reviewed-by: Erik Faye-Lund <kusmabite@xxxxxxxxx>
---
drivers/gpu/host1x/job.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c
index f32ae69a68c7..bee504406cfc 100644
--- a/drivers/gpu/host1x/job.c
+++ b/drivers/gpu/host1x/job.c
@@ -574,12 +574,20 @@ static inline int copy_gathers(struct host1x_job *job, struct device *dev)
size += g->words * sizeof(u32);
}
+ /*
+ * Try a non-blocking allocation from a higher priority pools first,
+ * as awaiting for the allocation here is a major performance hit.
+ */
job->gather_copy_mapped = dma_alloc_wc(dev, size, &job->gather_copy,
- GFP_KERNEL);
- if (!job->gather_copy_mapped) {
- job->gather_copy_mapped = NULL;
+ GFP_NOWAIT);
+
+ /* the higher priority allocation failed, try the generic-blocking */
+ if (!job->gather_copy_mapped)
+ job->gather_copy_mapped = dma_alloc_wc(dev, size,
+ &job->gather_copy,
+ GFP_KERNEL);
+ if (!job->gather_copy_mapped)
return -ENOMEM;
- }
job->gather_copy_size = size;
--
2.13.0
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