Re: [PATCH] powerpc: Linux cannot run with 0 cores
From: Paul E. McKenney <hidden>
Date: 2010-06-18 18:02:31
On Fri, Jun 18, 2010 at 10:33:06AM +1000, Anton Blanchard wrote:
If we configure with CONFIG_SMP=n or set NR_CPUS less than the number of SMT threads we will set the max cores property to 0 in the ibm,client-architecture-support structure. On new versions of firmware that understand this property it obliges and terminates our partition. Use DIV_ROUND_UP so we handle not only the CONFIG_SMP=n case but also the case where NR_CPUS isn't a multiple of the number of SMT threads.
Thank you, Anton!!! Acked-by: Paul E. McKenney <redacted> (Will test as soon as the system that hit this becomes available.)
quoted hunk ↗ jump to hunk
Signed-off-by: Anton Blanchard <redacted> --- Index: linux-2.6/arch/powerpc/kernel/prom_init.c ===================================================================--- linux-2.6.orig/arch/powerpc/kernel/prom_init.c 2010-06-17 09:08:20.000000000 +1000 +++ linux-2.6/arch/powerpc/kernel/prom_init.c 2010-06-17 09:10:02.000000000 +1000@@ -872,7 +872,7 @@ static void __init prom_send_capabilitie "ibm_architecture_vec structure inconsistent: 0x%x !\n", *cores); } else { - *cores = NR_CPUS / prom_count_smt_threads(); + *cores = DIV_ROUND_UP(NR_CPUS, prom_count_smt_threads()); prom_printf("Max number of cores passed to firmware: 0x%x\n", (unsigned long)*cores); }