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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2017-04-04 15:05:31 +0300 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2017-04-04 15:48:21 +0300 |
| commit | a7980a640cbd339aa80f406d1786a275a2c320bc (patch) | |
| tree | 48e7c5bf1a70b1a471657b5e5097de71a4ecd01c /lib/once.c | |
| parent | b1becb88268beb72df6495e35d3d76c138d215bb (diff) | |
| download | linux-a7980a640cbd339aa80f406d1786a275a2c320bc.tar.xz | |
drm/i915: Apply a cond_resched() to the saturated signaler
If the engine is continually completing nops, we can saturate the
signaler and keep it working indefinitely. This angers the NMI watchdog!
A good example is to disable semaphores on snb and run igt/gem_exec_nop -
the parallel, multi-engine workloads are more than sufficient to hog the
CPU, preventing the system from even processing ICMP echo replies.
v2: Tvrtko dug into cond_resched() on x86 and found that it only
depended upon preempt_count and not tif_need_resched() - which means
that we would always call schedule() at that point.
Fixes: c81d46138da6 ("drm/i915: Convert trace-irq to the breadcrumb waiter")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170404120531.10737-1-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Diffstat (limited to 'lib/once.c')
0 files changed, 0 insertions, 0 deletions