ACK: [PATCH][SRU][F] UBUNTU: SAUCE: drm/i915: prevent direct writeback from the shrinker

[Seth Forshee]

On Mon, Apr 20, 2020 at 04:19:01PM +0200, Andrea Righi wrote:
> BugLink: https://bugs.launchpad.net/bugs/1861359
> 
> The i915 shrinker can make the system unresponsive and kill interactive
> performance by swapping out dirty objects to reclaim more memory.
> 
> Avoid the lags by preventing to swap out dirty objects from any task
> (except kswapd).
> 
> This is not required in 5.5+, because it is properly fixed by commit
> 2850748ef876 ("drm/i915: Pull i915_vma_pin under the vm->mutex")
> 
> However, backporting this commit to 5.4 is not trivial and the
> regression potential is high. A simple change like this can be a
> reasonable compromise to prevent the problem and avoid the risk of
> introducing other bugs.
> 
> Fixes: 2d6692e642e7 ("drm/i915: Start writeback from the shrinker")
> Signed-off-by: Sultan Alsawaf <sultan.alsawaf at canonical.com>
> Signed-off-by: Andrea Righi <andrea.righi at canonical.com>

Acked-by: Seth Forshee <seth.forshee at canonical.com>