Re: [PATCH 1/2] drm/i915: Preallocate our mmu notifier workequeu to unbreak cpu hotplug deadlock

From: Chris Wilson
Date: Fri Oct 06 2017 - 05:24:39 EST

Quoting Daniel Vetter (2017-10-06 10:06:36)
> 4.14-rc1 gained the fancy new cross-release support in lockdep, which
> seems to have uncovered a few more rules about what is allowed and
> isn't.
> This one here seems to indicate that allocating a work-queue while
> holding mmap_sem is a no-go, so let's try to preallocate it.

But you haven't mentioned why we might want to preallocate to reduce the
mmap/mm_lock coverage anyway.