Chris Wilson e7571f7fd6 drm/i915: Break busywaiting for requests on pending signals ... The busywait in __i915_spin_request() does not respect pending signals and so may consume the entire timeslice for the task instead of returning to userspace to handle the signal. In the worst case this could cause a delay in signal processing of 20ms, which would be a noticeable jitter in cursor tracking. If a higher resolution signal was being used, for example to provide fairness of a server timeslices between clients, we could expect to detect some unfairness between clients (i.e. some windows not updating as fast as others). This issue was noticed when inspecting a report of poor interactivity resulting from excessively high __i915_spin_request usage. Fixes regression from commit 2def4ad99b [v4.2] Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Tue Apr 7 16:20:41 2015 +0100 drm/i915: Optimistically spin for the request completion v2: Try to assess the impact of the bug Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Cc: Jens Axboe <axboe@kernel.dk> Cc; "Rogozhkin, Dmitry V" <dmitry.v.rogozhkin@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Cc: Eero Tamminen <eero.t.tamminen@intel.com> Cc: "Rantala, Valtteri" <valtteri.rantala@intel.com> Cc: stable@vger.kernel.org Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1449833608-22125-2-git-send-email-chris@chris-wilson.co.uk (cherry picked from commit 91b0c352ac) Signed-off-by: Jani Nikula <jani.nikula@intel.com>		2015-12-22 12:55:01 +02:00
..
drm	drm/i915: Break busywaiting for requests on pending signals	2015-12-22 12:55:01 +02:00
host1x	gpu: host1x: Fix MLOCK's debug info	2015-10-02 14:40:12 +02:00
ipu-v3	gpu: ipu-v3: Assign of_node of child platform devices to corresponding ports	2015-11-24 11:30:17 +01:00
vga	vgaarb: fix signal handling in vga_get()	2015-12-11 14:04:44 +10:00
Makefile