Re: [PATCH] drm: Use idr_init_base(1) when using id==0 for invalid

Chris Wilson
2018-02-19T14:35:38Z

Quoting Christian König (2018-02-13 13:48:24)
> Am 12.02.2018 um 18:14 schrieb Ville Syrjälä:
> > On Mon, Feb 12, 2018 at 02:55:33PM +0000, Chris Wilson wrote:
> >> Use the new idr_init_base() function to create an IDR that knows id==0
> >> is never allocated as it maps to an invalid identifier. By knowing that
> >> id==0 is invalid, the IDR can start from id=1 instead avoiding the issue
> >> of having to start each lookup from the zeroth leaf as id==0 is always
> >> unused (and thus the tree-of-bitmaps indicate that is the first
> >> available).
> >>
> >> References: 6ce711f27500 ("idr: Make 1-based IDRs more efficient")
> >> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> >> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> >> Cc: Christian Konig <christian.koenig@amd.com>
> >> Cc: Dave Airlie <airlied@redhat.com>
> > Yep, looks like all of these pass start==1 to idr_alloc().
> > Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Acked-by: Christian König <christian.koenig@amd.com> as well.
>
> Probably going to do this for the command submission context handles in
> amdgpu as well.

Thanks for the review, pushed to drm-misc-next.

As noted, there are probably quite a few more idr's that we can move
over to idr_init_base(1), e.g. the KMS objects. If someone feels like a
small task?
-Chris
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org