[Intel-gfx] [PATCH] drm/i915: Drain the freed state from the tail of the next commit

[Chris Wilson]

On Mon, Feb 06, 2017 at 09:41:42AM +0100, Maarten Lankhorst wrote:
> Op 02-02-17 om 21:47 schreef Chris Wilson:
> > If we have any residual freed atomic state from earlier commits, flush
> > the freed list after performing the current modeset. This prevents the
> > freed list from ever-growing if userspace manages to starve the kernel
> > threads (i.e. we are never able to run our free state worker and
> > eventually the system may even oom).
> >
> > Fixes: eb955eee27d9 ("drm/i915: Move atomic state free from out of fence release")
> > Testcase: igt/kms_cursor/legacy/all-pipes-single-bo
> kms_cursor_legacy
> > Reported-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > ---
> >
> > Though the earlier patch is cc'ed for v4.10, I don't this fix to the fix
> > merits applying to v4.10 this late. The impact should be small, it takes
> > the deliberate abuse of RT tasks to starve the kernel so badly as that
> > the delayed free of the atomic state will cause system-wide consequences
> > (e.g. oom)
> Fixes the kms_cursor_legacy testcase, and the patch makes sense.
> 
> Reviewed-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>

Thanks for the catch, pushed.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre