• Andrew Morton's avatar
    [PATCH] x86: don't initialise cpu_possible_map to all ones · 7a8ef1cb
    Andrew Morton authored
    Initialising cpu_possible_map to all-ones with CONFIG_HOTPLUG_CPU means that
    
    a) All for_each_cpu() loops will iterate across all NR_CPUS CPUs, rather
       than over possible ones.  That can be quite expensive.
    
    b) Soon we'll be allocating per-cpu areas only for possible CPUs.  So with
       CPU_MASK_ALL, we'll be wasting memory.
    
    I also switched voyager over to not use CPU_MASK_ALL in the non-CPU-hotplug
    case.  Should be OK..
    
    I note that parisc is also using CPU_MASK_ALL.  Suggest that it stop doing
    that.
    
    Cc: James Bottomley <James.Bottomley@steeleye.com>
    Cc: Kyle McMartin <kyle@mcmartin.ca>
    Cc: Paul Jackson <pj@sgi.com>
    Cc: Ashok Raj <ashok.raj@intel.com>
    Cc: Zwane Mwaikambo <zwane@linuxpower.ca>
    Cc: Paul Jackson <pj@sgi.com>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    7a8ef1cb
voyager_smp.c 51.4 KB