> -----Original Message----- > From: Christian König [mailto:deathsimple@xxxxxxxxxxx] > Sent: Friday, September 14, 2012 4:49 AM > To: Jerome Glisse > Cc: Alex Deucher; Cherkasov, Dmitrii; linux-kernel@xxxxxxxxxxxxxxx; dri- > devel@xxxxxxxxxxxxxxxxxxxxx; Deucher, Alexander; Dave Airlie; Dmitry > Cherkasov > Subject: Re: [PATCH] Add 2-level GPUVM pagetables support to radeon > driver. > > On 13.09.2012 20:42, Jerome Glisse wrote: > > On Thu, Sep 13, 2012 at 2:37 PM, Alex Deucher <alexdeucher@xxxxxxxxx> > wrote: > >> On Thu, Sep 13, 2012 at 2:17 PM, Jerome Glisse <j.glisse@xxxxxxxxx> > wrote: > >>> On Thu, Sep 13, 2012 at 10:13 AM, Dmitry Cherkasov > >>> <dcherkassov@xxxxxxxxx> wrote: > >>>> PDE/PTE update code uses CP ring for memory writes. > >>>> All page table entries are preallocated for now in alloc_pt(). > >>>> > >>>> It is made as whole because it's hard to divide it to several patches > >>>> that compile and doesn't break anything being applied separately. > >>>> > >>>> Tested on cayman card. > >>>> > >>>> Signed-off-by: Dmitry Cherkasov <Dmitrii.Cherkasov@xxxxxxx> > >>>> --- > >>>> I couldn't test in on SI card, so would be happy if someone could check > it there. > >>> I wonder how this could have work as you don't set > >>> PAGE_TABLE_BLOCK_SIZE field so each page directory entry cover only 1 > >>> page. > >> I think PAGE_TABLE_BLOCK_SIZE refers number of 4k pages used for PTE > >> entries per PDE. E.g., 1 4k page contains 512 64 bit PTEs. so if > >> BLOCK_SIZE is set to 1 page, each PDE points to 1 page (4k) or PTE > >> entries. If BLOCK_SIZE is 2, each PDE points to 2 pages (8k) or PTEs, > >> etc. > >> > >> Alex > >> > > If so then it's ok > Yeah, minor nitpick: BLOCK_SIZE seems to be number of 4k pages in a page > directory entry minus 1. > > So with a BLOCK_SIZE of 0 you get one 4K page and with a BLOCK_SIZE of 1 > you get 8K, etc... It's LOG2: PAGE_TABLE_BLOCK_SIZE 27:24 0x0 log2 number of pages in page table block (default = 1 page) > > Christian. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
