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    x86: resurrect proper handling of maxcpus= kernel option (v2) · 23b49c19
    Max Krasnyansky 提交于
    For some reason we had two parsers registered for maxcpus=. One in init/main.c
    and another in arch/x86/smpboot.c. So I nuked the one in arch/x86.
    
    Also 64-bit kernels used to handle maxcpus= as documented in
    Documentation/cpu-hotplug.txt. CPUs with 'id > maxcpus' are initialized
    but not booted. 32-bit version for some reason ignored them even though
    all the infrastructure for booting them later is there.
    
    In the current mainline both 64 and 32 bit versions are broken.
    This patch restores the correct behaviour. I've tested x86_64 version on
    4- and 8- way Core2 and 2-way Opteron based machines. Various config
    combinations SMP, !SMP, CPU_HOTPLUG, !CPU_HOTPLUG.
    Booted with maxcpus=1 and maxcpus=4, etc. Everything is working as expected.
    
    So far we've received two reports from different people confirming that 32-bit
    version also works fine, both on dual core laptops and 16way server machines.
    
    [v2: This version fixes visws breakage pointed out by Ingo.]
    Signed-off-by: NMax Krasnyansky <maxk@qualcomm.com>
    Cc: lizf@cn.fujitsu.com
    Cc: jeff.chua.linux@gmail.com
    Signed-off-by: NIngo Molnar <mingo@elte.hu>
    23b49c19
apic_32.c 43.0 KB