drm/i915: Throw away the active object retirement complexity
authorChris Wilson <chris@chris-wilson.co.uk>
Fri, 21 Jun 2019 18:37:59 +0000 (19:37 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Fri, 21 Jun 2019 18:47:51 +0000 (19:47 +0100)
commita93615f900bd19b59e74e04f7d8d4663ee5ea68f
tree02e0dceeb8c404520f4d5aa10b2a106199c1b52d
parent5361db1a33c7e2d58af7df045d4d3ddd4c87ab56
drm/i915: Throw away the active object retirement complexity

Remove the accumulated optimisations that we have for i915_vma_retire
and reduce it to the bare essential of tracking the active object
reference. This allows us to only use atomic operations, and so will be
able to avoid the struct_mutex requirement.

The principal loss here is the shrinker MRU bumping, so now if we have
to shrink, we will do so in much more random order and more likely to
try and shrink recently used objects. That is a nuisance, but shrinking
active objects is a second step we try to avoid and will always be a
system-wide performance issue.

The other loss is here is in the automatic pruning of the
reservation_object when idling. This is not as large an issue as upon
reservation_object introduction as now adding new fences into the object
replaces already signaled fences, keeping the array compact. But we do
lose the auto-expiration of stale fences and unused arrays. That may be
a noticeable problem for which we need to re-implement autopruning.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190621183801.23252-3-chris@chris-wilson.co.uk
drivers/gpu/drm/i915/gem/i915_gem_object.c
drivers/gpu/drm/i915/gem/i915_gem_object.h
drivers/gpu/drm/i915/gem/i915_gem_object_types.h
drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
drivers/gpu/drm/i915/gt/intel_lrc.c
drivers/gpu/drm/i915/gt/intel_ringbuffer.c
drivers/gpu/drm/i915/gt/selftest_hangcheck.c
drivers/gpu/drm/i915/i915_debugfs.c
drivers/gpu/drm/i915/i915_gem_batch_pool.c
drivers/gpu/drm/i915/i915_vma.c