sparse: fix x86_64 domU SMP cpu_present map
PATCH 1/1 sparse: fix x86_64 domU SMP cpu_present map
Changeset 7419 introduced a check for DOM0 before setting a bit in the cpu_present map. This prevents domU SMP kernels without HOTPLUG_CPU support from booting. Secondary cpus need to be present and online before init/main.c:do_basic_setup() calls init_workqueues() (which initializes per-cpu workqueues).
Without this patch, non HOTPLUG_CPU enabled kernels hang when flushing cpu workqueues as the spinlock in the structure is never initialized (it has a default value of zero which means the lock has been acquired on x86).
I've tested this patch on x86_64 SMP, x86_32 SMP, with and without HOTPLUG_CPU set. See bugzilla [1]#347 for more details.
Please apply.
1. http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=347
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Ryan Harper Software Engineer; Linux Technology Center IBM Corp., Austin, Tx (512) 838-9253 T/L: 678-9253 [email protected] diffstat output: smpboot.c | 3 +-- 1 files changed, 1 insertion(+), 2 deletions(-) Signed-off-by: Ryan Harper <[email protected]> --- diff -r ae2e13795c63 linux-2.6-xen-sparse/arch/xen/kernel/smpboot.c --- a/linux-2.6-xen-sparse/arch/xen/kernel/smpboot.c Tue Nov 1 18:13:06 2005 +++ b/linux-2.6-xen-sparse/arch/xen/kernel/smpboot.c Tue Nov 1 14:15:08 2005 @@ -236,8 +236,7 @@ make_page_readonly((void *)cpu_gdt_descr[cpu].address); cpu_set(cpu, cpu_possible_map); - if (xen_start_info->flags & SIF_INITDOMAIN) - cpu_set(cpu, cpu_present_map); + cpu_set(cpu, cpu_present_map); vcpu_prepare(cpu); }