drm/i915/buddy: document the unused header bits

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The largest possible order is (63-PAGE_SHIFT), given that our min chunk
size is PAGE_SIZE. With that we should only need at most 6 bits to
represent all possible orders, giving us back 4 bits for other potential
uses.  Include a simple selftest to verify this.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20210126103019.177622-1-matthew.auld@intel.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

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Matthew Auld 2021-01-26 10:30:19 +00:00 • committed by Daniel Vetter

parent b3f0c15a8e

commit a29a22917d

3 changed files with 56 additions and 2 deletions

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3

drivers/gpu/drm/i915/i915_buddy.c

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7

drivers/gpu/drm/i915/i915_buddy.h

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48

drivers/gpu/drm/i915/selftests/i915_buddy.c

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