drm/i915/gem: Avoid implicit vmap for highmem on x86-32

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On 32b, highmem using a finite set of indirect PTE (i.e. vmap) to provide
virtual mappings of the high pages.  As these are finite, map_new_virtual()
must wait for some other kmap() to finish when it runs out. If we map a
large number of objects, there is no method for it to tell us to release
the mappings, and we deadlock.

However, if we make an explicit vmap of the page, that uses a larger
vmalloc arena, and also has the ability to tell us to release unwanted
mappings. Most importantly, it will fail and propagate an error instead
of waiting forever.

Fixes: fb8621d3be ("drm/i915: Avoid allocating a vmap arena for a single page") #x86-32
References: e87666b52f ("drm/i915/shrinker: Hook up vmap allocation failure notifier")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Cc: <stable@vger.kernel.org> # v4.7+
Link: https://patchwork.freedesktop.org/patch/msgid/20200915091417.4086-1-chris@chris-wilson.co.uk

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Chris Wilson 2020-09-15 10:14:15 +01:00

parent e0ee152fce

commit 060bb115c2

1 changed files with 24 additions and 2 deletions

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drivers/gpu/drm/i915/gem/i915_gem_pages.c

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