[Intel-gfx] ✓ Fi.CI.BAT: success for drm/i915: Don't call synchronize_rcu_expedited under struct_mutex

[Chris Wilson]

On Fri, Apr 07, 2017 at 09:18:17AM -0000, Patchwork wrote:
> == Series Details ==
> 
> Series: drm/i915: Don't call synchronize_rcu_expedited under struct_mutex
> URL   : https://patchwork.freedesktop.org/series/22646/
> State : success
> 
> == Summary ==
> 
> Series 22646v1 drm/i915: Don't call synchronize_rcu_expedited under struct_mutex
> https://patchwork.freedesktop.org/api/1.0/series/22646/revisions/1/mbox/

Slow mbox. So reply here instead.

Hmm, so that fixes the immediate problem with struct_mutex, but there is
still a danger that we are underneath some other mutex that is being
waited upon. I think it is too dangerous to live and that kswapd should
have the role of expediting the RCU cleanup.

Since the patch improves the situation,
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>

But please do follow up with a 
- synchronize_rcu_expedited();
+ /* We rely on the system flushing the RCU slabs to free our structs */
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre