• Zwane Mwaikambo's avatar
    [PATCH] i386 CPU hotplug · f3705136
    Zwane Mwaikambo authored
    (The i386 CPU hotplug patch provides infrastructure for some work which Pavel
    is doing as well as for ACPI S3 (suspend-to-RAM) work which Li Shaohua
    <shaohua.li@intel.com> is doing)
    The following provides i386 architecture support for safely unregistering and
    registering processors during runtime, updated for the current -mm tree.  In
    order to avoid dumping cpu hotplug code into kernel/irq/* i dropped the
    cpu_online check in do_IRQ() by modifying fixup_irqs().  The difference being
    that on cpu offline, fixup_irqs() is called before we clear the cpu from
    cpu_online_map and a long delay in order to ensure that we never have any
    queued external interrupts on the APICs.  There are additional changes to s390
    and ppc64 to account for this change.
    2) disable local APIC timer on dead cpus.
    3) Disable preempt around irq balancing to prevent CPUs going down.
    4) Print irq stats for all possible cpus.
    5) Debugging check for interrupts on offline cpus.
    6) Hacky fixup_irqs() to redirect irqs when cpus go off/online.
    7) play_dead() for offline cpus to spin inside.
    8) Handle offline cpus set in flush_tlb_others().
    9) Grab lock earlier in smp_call_function() to prevent CPUs going down.
    10) Implement __cpu_disable() and __cpu_die().
    11) Enable local interrupts in cpu_enable() after fixup_irqs()
    12) Don't fiddle with NMI on dead cpu, but leave intact on other cpus.
    13) Program IRQ affinity whilst cpu is still in cpu_online_map on offline.
    Signed-off-by: default avatarZwane Mwaikambo <zwane@linuxpower.ca>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>