5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chris Wilson chris@chris-wilson.co.uk
[ Upstream commit c877bed82e1017c102c137d432933ccbba92c119 ]
One impact of commit 047a1b877ed4 ("dma-buf & drm/amdgpu: remove dma_resv workaround") is that it stores many, many more fences. Whereas adding an exclusive fence used to remove the shared fence list, that list is now preserved and the write fences included into the list. Not just a single write fence, but now a write/read fence per context. That causes us to have to track more fences than before (albeit half of those are redundant), and we trigger more interrupts for multi-engine workloads.
As part of reducing the impact from handling more signaling, we observe we only need to kick the signal worker after adding a fence iff we have good cause to believe that there is work to be done in processing the fence i.e. we either need to enable the interrupt or the request is already complete but we don't know if we saw the interrupt and so need to check signaling.
References: 047a1b877ed4 ("dma-buf & drm/amdgpu: remove dma_resv workaround") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Signed-off-by: Karolina Drobnik karolina.drobnik@intel.com Reviewed-by: Andi Shyti andi.shyti@linux.intel.com Signed-off-by: Rodrigo Vivi rodrigo.vivi@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/d7b953c7a4ba747c8196a164e2f8c5... Stable-dep-of: 70cb9188ffc7 ("drm/i915/gt: Disarm breadcrumbs if engines are already idle") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c index 209cf265bf746..e8cd7effea2b0 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c @@ -398,7 +398,8 @@ static void insert_breadcrumb(struct i915_request *rq) * the request as it may have completed and raised the interrupt as * we were attaching it into the lists. */ - irq_work_queue(&b->irq_work); + if (!b->irq_armed || __i915_request_is_complete(rq)) + irq_work_queue(&b->irq_work); }
bool i915_request_enable_breadcrumb(struct i915_request *rq)