[Intel-gfx] [PATCH 7/7] drm/i915: Trim unused workaround list entries

[Chris Wilson]

Quoting Tvrtko Ursulin (2018-11-30 17:44:12)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> The new workaround list allocator grows the list in chunks so will end up
> with some unused space. Trim it when the initialization phase is done to
> free up a tiny bit of slab.
> 
> v2:
>  * Simplify with kmemdup. (Chris Wilson)
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_workarounds.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_workarounds.c b/drivers/gpu/drm/i915/intel_workarounds.c
> index 3e6b388ea022..9d876d554e57 100644
> --- a/drivers/gpu/drm/i915/intel_workarounds.c
> +++ b/drivers/gpu/drm/i915/intel_workarounds.c
> @@ -55,6 +55,19 @@ static void wa_init_start(struct i915_wa_list *wal, const char *name)
>  
>  static void wa_init_finish(struct i915_wa_list *wal)
>  {
> +       /* Trim unused entries. */
> +       if (wal->count < wal->__size) {
> +               struct i915_wa *list = kmemdup(wal->list,
> +                                              wal->count * sizeof(*list),
> +                                              GFP_KERNEL);
> +
> +               if (list) {
> +                       kfree(wal->list);
> +                       wal->list = list;
> +                       wal->__size = wal->count;

Hmm. We could kill __size entirely if you reallocated on 
is_power_of_two(wal->count).

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris