> Am 26.01.2016 um 06:41 schrieb David Gibson <da...@gibson.dropbear.id.au>: > >> On Mon, Jan 25, 2016 at 09:36:40PM +0100, Alexander Graf wrote: >> >> >>> On 01/25/2016 12:10 PM, David Gibson wrote: >>>> On Mon, Jan 25, 2016 at 04:15:42PM +1100, David Gibson wrote: >>>> Encoding of page sizes on 64-bit hash MMUs for Power is rather arcane, >>>> involving control bits in both the SLB and HPTE. At present we >>>> support a few of the options, but far fewer than real hardware. >>>> >>>> We're able to get away with that in practice, because guests use a >>>> device tree property to determine which page sizes are available and >>>> we are setting that to match. However, the fact that the actual code >>>> doesn't necessarily what we put into the table of available page sizes >>>> is another ugliness. >>>> >>>> This series makes a number of cleanups to the page size handling. The >>>> upshot is that afterwards the softmmu code operates off the same page >>>> size encoding table that is advertised to the guests, ensuring that >>>> they will be in sync. >>>> >>>> Finally, we extend the table of allowed sizes for POWER7 and POWER8 to >>>> include the options allowed in hardware (including MPSS). We can fix >>>> other hash MMU based CPUs in future if anyone cares enough. >>>> >>>> Please review, and I'll fold into ppc-for-2.6 for my next pull. >>> Bother, somehow missed a serious bug in here that's causing >>> oops-on-boot. Sorry, still tracking it down. >> >> I still have no idea where your bug is (bisect probably should get you there >> pretty quick), > > Alas, no, because the bug only triggers once all the page sizes are > added for POWER8 in the last patch. > > Luckily I found it anyway (see earlier reply). > >> but the overall concept sounds very reasonable to me. Please >> benchmark performance before and after in the next cover letter also >> :) > > Hrm.. as always the question is what benchmark?
For this "time" on a simple kernel boot+automatic shutdown sequence should be enough. Alex > >> >> Reviewed-by: Alexander Graf <ag...@suse.de> >> >> Alex > > -- > David Gibson | I'll have my music baroque, and my code > david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ > | _way_ _around_! > http://www.ozlabs.org/~dgibson
