]> git.baikalelectronics.ru Git - kernel.git/commit
drm/i915: Track the context's seqno in its own timeline HWSP
authorChris Wilson <chris@chris-wilson.co.uk>
Mon, 28 Jan 2019 18:18:11 +0000 (18:18 +0000)
committerChris Wilson <chris@chris-wilson.co.uk>
Mon, 28 Jan 2019 19:07:09 +0000 (19:07 +0000)
commitfe81e2d4660c47410dd46cad2a384b1168d1ef75
tree1078ed4c54d8457b3768ee71422970144c05c053
parent484a23f77d1969ebba281b2a94cbb5eac6fe8f6d
drm/i915: Track the context's seqno in its own timeline HWSP

Now that we have allocated ourselves a cacheline to store a breadcrumb,
we can emit a write from the GPU into the timeline's HWSP of the
per-context seqno as we complete each request. This drops the mirroring
of the per-engine HWSP and allows each context to operate independently.
We do not need to unwind the per-context timeline, and so requests are
always consistent with the timeline breadcrumb, greatly simplifying the
completion checks as we no longer need to be concerned about the
global_seqno changing mid check.

One complication though is that we have to be wary that the request may
outlive the HWSP and so avoid touching the potentially danging pointer
after we have retired the fence. We also have to guard our access of the
HWSP with RCU, the release of the obj->mm.pages should already be RCU-safe.

At this point, we are emitting both per-context and global seqno and
still using the single per-engine execution timeline for resolving
interrupts.

v2: s/fake_complete/mark_complete/

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190128181812.22804-5-chris@chris-wilson.co.uk
drivers/gpu/drm/i915/i915_gem.c
drivers/gpu/drm/i915/i915_request.c
drivers/gpu/drm/i915/i915_request.h
drivers/gpu/drm/i915/i915_reset.c
drivers/gpu/drm/i915/i915_timeline.c
drivers/gpu/drm/i915/intel_engine_cs.c
drivers/gpu/drm/i915/intel_lrc.c
drivers/gpu/drm/i915/intel_ringbuffer.c
drivers/gpu/drm/i915/selftests/i915_timeline.c
drivers/gpu/drm/i915/selftests/mock_engine.c