drm/i915: Stop marking the unaccessible scratch page as UC
authorChris Wilson <chris@chris-wilson.co.uk>
Mon, 22 Aug 2016 07:44:29 +0000 (08:44 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Mon, 22 Aug 2016 10:01:47 +0000 (11:01 +0100)
commit14daa63b277b73a91ca084acee9e31365c7283e9
treed56126cf73b5f2fcbe67ddbf286f92ab4af15d31
parent5f4b091aa200caa118520b6918b94e019f532dcf
drm/i915: Stop marking the unaccessible scratch page as UC

Since by design, if not entirely by practice, nothing is allowed to
access the scratch page we use to background fill the VM, then we do not
need to ensure that it is coherent between the CPU and GPU.
set_pages_uc() does a stop_machine() after changing the PAT, and that
significantly impacts upon context creation throughput.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20160822074431.26872-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
drivers/gpu/drm/i915/i915_gem_gtt.c