Chris Wilson <ch...@chris-wilson.co.uk> writes: > On Fri, Mar 10, 2017 at 10:04:16AM +0000, Chris Wilson wrote: >> On Fri, Mar 10, 2017 at 11:58:44AM +0200, Mika Kuoppala wrote: >> > Chris Wilson <ch...@chris-wilson.co.uk> writes: >> > >> > > We only need to clflush those cachelines that we have validated to be >> > > read by the GPU. Userspace typically fills the batch length in >> > > correctly, the exceptions tend to be explicit tests within igt. >> > > >> > > Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> >> > > --- >> > > drivers/gpu/drm/i915/i915_cmd_parser.c | 3 ++- >> > > 1 file changed, 2 insertions(+), 1 deletion(-) >> > > >> > > diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c >> > > b/drivers/gpu/drm/i915/i915_cmd_parser.c >> > > index 21b1cd917d81..b9ce9a6881ea 100644 >> > > --- a/drivers/gpu/drm/i915/i915_cmd_parser.c >> > > +++ b/drivers/gpu/drm/i915/i915_cmd_parser.c >> > > @@ -1331,7 +1331,8 @@ int intel_engine_cmd_parser(struct intel_engine_cs >> > > *engine, >> > > } >> > > >> > > if (ret == 0 && needs_clflush_after) >> > > - drm_clflush_virt_range(shadow_batch_obj->mm.mapping, >> > > batch_len); >> > > + drm_clflush_virt_range(shadow_batch_obj->mm.mapping, >> > > + (void *)cmd - >> > > shadow_batch_obj->mm.mapping); >> > >> > (void *)cmd - ptr_mask_bit(shadow_batch_obj->mm.mapping) >> > >> > We get away as the wb mapping being zero but for correctness. >> >> The low bits of mm.mapping cannot change the cacheline and so doesn't >> affect the clflush. Same as before. > > Although, not quite the same as before as before we didn't use a fixed > end-point and so it could overshoot by a cacheline, even across a page > boundary.
And there could be PAGE_MASK worth of lowbits. -Mika > -Chris > > -- > Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
