On Thu, Feb 10, 2022 at 10:36:33AM -0800, Michael Cheng wrote:
> Drop invalidate_csb_entries and directly call drm_clflush_virt_range.
> This allows for one less function call, and prevent complier errors when
> building for non-x86 architectures.
>
> v2(Michael Cheng): Drop invalidate_csb_entries function and directly
> invoke drm_clflush_virt_range. Thanks to Tvrtko for the
> sugguestion.
>
> v3(Michael Cheng): Use correct parameters for drm_clflush_virt_range.
> Thanks to Tvrtko for pointing this out.
>
> Signed-off-by: Michael Cheng <michael.cheng@xxxxxxxxx>
> ---
> .../gpu/drm/i915/gt/intel_execlists_submission.c | 13 ++++---------
> 1 file changed, 4 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> index 9bb7c863172f..6186a5e4b191 100644
> --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> @@ -1646,12 +1646,6 @@ cancel_port_requests(struct intel_engine_execlists * const execlists,
> return inactive;
> }
>
> -static void invalidate_csb_entries(const u64 *first, const u64 *last)
> -{
> - clflush((void *)first);
> - clflush((void *)last);
> -}
> -
> /*
> * Starting with Gen12, the status has a new format:
> *
> @@ -1999,7 +1993,7 @@ process_csb(struct intel_engine_cs *engine, struct i915_request **inactive)
> * the wash as hardware, working or not, will need to do the
> * invalidation before.
> */
> - invalidate_csb_entries(&buf[0], &buf[num_entries - 1]);
> + drm_clflush_virt_range(&buf[0], num_entries * sizeof(buf[0]));
>
> /*
> * We assume that any event reflects a change in context flow
> @@ -2783,8 +2777,9 @@ static void reset_csb_pointers(struct intel_engine_cs *engine)
>
> /* Check that the GPU does indeed update the CSB entries! */
> memset(execlists->csb_status, -1, (reset_value + 1) * sizeof(u64));
> - invalidate_csb_entries(&execlists->csb_status[0],
> - &execlists->csb_status[reset_value]);
> + drm_clflush_virt_range(&execlists->csb_status[0],
I think you could simplify the parameter slightly by just writing it as
'execlists->csb_status'
> + execlists->csb_size *
> + sizeof(execlists->csb_status[0]));
The existing code only issues a clflush for the first and last entries
rather than the range from 0..reset_value, but since there are only a
maximum of 12 u64 entries, which fits into two cachelines, the end
result should be the same either way.
Reviewed-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
>
> /* Once more for luck and our trusty paranoia */
> ENGINE_WRITE(engine, RING_CONTEXT_STATUS_PTR,
> --
> 2.25.1
>
--
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation
(916) 356-2795
