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? While you may just answer the questions posed, this looks clumsy: > + *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
