On Mon, Aug 31, 2015 at 07:42:34PM +0100, Chris Wilson wrote: > On Mon, Aug 31, 2015 at 06:59:40PM +0200, Michał Winiarski wrote: > > On each call to gen8_alloc_va_range_3lvl we're allocating temporary > > bitmaps needed for error handling. Unfortunately, when we increase > > address space size (48b ppgtt) we do additional (512 - 4) calls to > > kcalloc, increasing latency between exec and actual start of execution > > on the GPU. Let's just do a single kcalloc and setup proper offsets in > > an array, we can also drop the size from free_gen8_temp_bitmaps since > > it's no longer needed. > > > > v2: Use GFP_TEMPORARY to make the allocations reclaimable. > > > > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> > > Cc: Michel Thierry <michel.thierry@xxxxxxxxx> > > Signed-off-by: Michał Winiarski <michal.winiarski@xxxxxxxxx> > > Is there any reason why it remains a 2D array though? Looks like it can > be reduced to a single block. And why do we allocate a bitmap for the > whole address space rather than just the range being allocated? No particular reason, let's try that. It's not the whole address space... Quite possibly just 1/512 of the whole address space, as the PUD is handled in gen8_alloc_va_range_4lvl. I guess it was done to simplify... something, although I can't tell what at this point. > While you may just answer the questions posed, this looks clumsy: Yup - missed that, I was using temp variable before sending the patch. -Michał > > > + *pts = kcalloc(pdpes * BITS_TO_LONGS(I915_PDES), > > + sizeof(unsigned long), GFP_TEMPORARY); > > + if (!*pts) > > + goto err_out; > > + > > + for (i = 0; i < pdpes; i++) > > + pts[i] = *pts + i * BITS_TO_LONGS(I915_PDES); > > i..e > > for (i = 1; i < pdpes; i++) > pts[i] = pts[0] + i* BITS_TO_LONGS(I915_PDES); > > raises fewer questions. > -Chris > > -- > Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
