On 11/10/2014 06:20, Thomas Bogendoerfer wrote: > On Mon, Nov 10, 2014 at 11:51:06AM +0100, Ralf Baechle wrote: >> Thomas, >> >> can you test CONFIG_TRANSPARENT_HUGEPAGE on an IP28? >> >> All in all the R10000's TLB is unproblematic; my gut feeling is that >> rather something else specific to IP27 is spoiling the broth. > > I'll give it a spin later today. > > Thomas. Try testing with and without CONFIG_HUGETLBFS in the kernel. File systems -> Pseudo filesystems -> HugeTLB file system support So far, it seems adding that option in with CONFIG_TRANSPARENT_HUGEPAGE makes both IP27 and IP30 behave. Without, I get data bus errors or segfaults on IP27 running Gentoo's "emerge" program on PAGE_SIZE_4K. IP30 seems to be fine on an R12000 with or without that option, but I only have a dual R12K module to test against. I've only had the R14K dual module for a few days, and I could not reproduce the bus errors on that module, either. So I wonder if there is something funny with the hardware on the single R14K module, which I did get IBE's on before. And whether that will behave once CONFIG_HUGETLBFS is in the kernel. If so, maybe the fix is to make CONFIG_HUGETLBFS automatically selected if CONFIG_TRANSPARENT_HUGEPAGE? --J
