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  • Michael Ellerman's avatar
    powerpc: Dynamically allocate pacas · 1426d5a3
    Michael Ellerman authored
    
    
    On 64-bit kernels we currently have a 512 byte struct paca_struct for
    each cpu (usually just called "the paca"). Currently they are statically
    allocated, which means a kernel built for a large number of cpus will
    waste a lot of space if it's booted on a machine with few cpus.
    
    We can avoid that by only allocating the number of pacas we need at
    boot. However this is complicated by the fact that we need to access
    the paca before we know how many cpus there are in the system.
    
    The solution is to dynamically allocate enough space for NR_CPUS pacas,
    but then later in boot when we know how many cpus we have, we free any
    unused pacas.
    
    Signed-off-by: default avatarMichael Ellerman <michael@ellerman.id.au>
    Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
    1426d5a3