[Intel-gfx] [PATCH v2 5/6] drm/i915: Reduce pointer indirection during cmd parser lookup

[Ville Syrjälä]

On Fri, Nov 20, 2015 at 03:34:22PM +0000, Chris Wilson wrote:
> On Fri, Nov 20, 2015 at 05:27:43PM +0200, Ville Syrjälä wrote:
> > On Fri, Nov 20, 2015 at 10:56:00AM +0000, Chris Wilson wrote:
> > > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > > ---
> > >  drivers/gpu/drm/i915/i915_cmd_parser.c | 51 ++++++++--------------------------
> > >  drivers/gpu/drm/i915/i915_drv.h        |  4 ++-
> > >  2 files changed, 14 insertions(+), 41 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
> > > index cfd07bfe6e75..ea9df2bb87de 100644
> > > --- a/drivers/gpu/drm/i915/i915_cmd_parser.c
> > > +++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
> > > @@ -113,7 +113,7 @@
> > >  
> > >  /*            Command                          Mask   Fixed Len   Action
> > >  	      ---------------------------------------------------------- */
> > > -static const struct drm_i915_cmd_descriptor common_cmds[] = {
> > > +static struct drm_i915_cmd_descriptor common_cmds[] = {
> > 
> > I'm a little sad to see the const gone. All this gets moved out of
> > rodata.
> 
> I'm open to having this refused. Pretty much both of 4 & 5 can be
> ignored after reducing the number of hash collisions in 6. Though not
> having to duplicate the memory for the hash tables is nice.

I don't have a strong opinion either way. On one hand rodata is nice,
on the other hand simplicity from avoiding the kmalloc()s is nice.

-- 
Ville Syrjälä
Intel OTC