On Tue, Apr 17, 2018 at 09:28:42AM +0530, Bharata B Rao wrote: > On Mon, Apr 16, 2018 at 07:47:29PM +0300, Serhii Popovych wrote: > > Bharata B Rao wrote: > > > On Wed, Apr 11, 2018 at 02:41:59PM -0400, Serhii Popovych wrote: > > >> Now recent kernels (i.e. since linux-stable commit a346137e9142 > > >> ("powerpc/numa: Use ibm,max-associativity-domains to discover possible > > >> nodes") > > >> support this property to mark initially memory-less NUMA nodes as > > >> "possible" > > >> to allow further memory hot-add to them. > > >> > > >> Advertise this property for pSeries machines to let guest kernels detect > > >> maximum supported node configuration and benefit from kernel side change > > >> when hot-add memory to specific, possibly empty before, NUMA node. > > >> > > >> Signed-off-by: Serhii Popovych <spopo...@redhat.com> > > >> --- > > >> hw/ppc/spapr.c | 10 ++++++++++ > > >> 1 file changed, 10 insertions(+) > > >> > > >> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > > >> index a81570e..c05bbad 100644 > > >> --- a/hw/ppc/spapr.c > > >> +++ b/hw/ppc/spapr.c > > >> @@ -910,6 +910,13 @@ static void spapr_dt_rtas(sPAPRMachineState *spapr, > > >> void *fdt) > > >> 0, cpu_to_be32(SPAPR_MEMORY_BLOCK_SIZE), > > >> cpu_to_be32(max_cpus / smp_threads), > > >> }; > > >> + uint32_t maxdomains[] = { > > >> + cpu_to_be32(4), > > >> + cpu_to_be32(0), > > >> + cpu_to_be32(0), > > >> + cpu_to_be32(0), > > >> + cpu_to_be32(nb_numa_nodes - 1), > > >> + }; > > >> > > >> _FDT(rtas = fdt_add_subnode(fdt, 0, "rtas")); > > >> > > >> @@ -946,6 +953,9 @@ static void spapr_dt_rtas(sPAPRMachineState *spapr, > > >> void *fdt) > > >> _FDT(fdt_setprop(fdt, rtas, "ibm,associativity-reference-points", > > >> refpoints, sizeof(refpoints))); > > >> > > >> + _FDT(fdt_setprop(fdt, rtas, "ibm,max-associativity-domains", > > >> + maxdomains, sizeof(maxdomains))); > > >> + > > >> _FDT(fdt_setprop_cell(fdt, rtas, "rtas-error-log-max", > > >> RTAS_ERROR_LOG_MAX)); > > >> _FDT(fdt_setprop_cell(fdt, rtas, "rtas-event-scan-rate", > > > > > > This commit causes hash guest with latest guest kernel to hang at early > > > boot. > > > > I use v4.16 tag from stable and can't reproduce on P8 machine reported > > issue. > > > > Could you please share more details about your setup, kernel commit id > > you spot problem? > > I am on 4.16.0-rc7 (commit id: 0b412605ef5f) > > BTW this happens only for non-NUMA guest.
Ah, that might explain it. With no NUMA nodes specified, I think this code will put a -1 into the max-associativity-domains property, which is probably causing the mess. If we don't have NUMA (nb_numa_nodes == 0) we probably want to either omit the property entirely, or clamp that 5th cell to 0. -- 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
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