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    SubjectRe: [PATCH] x86-32: Allocate irq stacks seperate from percpu area
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    Le mercredi 27 octobre 2010 à 17:35 +0200, Tejun Heo a écrit :

    > Hmmm, okay. Can you please print out early_cpu_to_node() output for
    > each cpu from arch/x86/kernel/setup_percpu.c::setup_per_cpu_areas()?
    > BTW, some clarifications.
    >
    > * In the pcpu-alloc debug message, the n of [n] might not necessarily
    > match the NUMA node.
    >
    > * I was confused before. If CPU distance reported by
    > early_cpu_to_node() is greater than LOCAL_DISTANCE (ie. NUMA
    > configuration), cpus will always belong to different [n]. What gets
    > adjusted is the size of each unit.
    >
    > * No matter what, here, the end result is correct. As there's no low
    > memory on node 1, it doesn't matter how the groups are organized in
    > the first chunk as long as embedding is used. And for other chunks,
    > pages for each cpu are allocated separatedly w/ cpu_to_node() anyway
    > so NUMA affinity will be correct, again, regardless of the group
    > organization.
    >
    > Thanks.
    >

    Will do in a few moment, once I recover from frozen machine :(
    (See end of this mail)

    Thanks !

    By the way, booting with hashdist=1 to make alloc_large_system_hash()
    use vmalloc() show that only pages from node 0 were used at boot.

    # grep alloc_large /proc/vmallocinfo
    0xf7a01000-0xf7a82000 528384 alloc_large_system_hash+0x144/0x1d9 pages=128 vmalloc N0=128
    0xf7a83000-0xf7ac4000 266240 alloc_large_system_hash+0x144/0x1d9 pages=64 vmalloc N0=64
    0xf7b11000-0xf7b32000 135168 alloc_large_system_hash+0x144/0x1d9 pages=32 vmalloc N0=32
    0xf7b33000-0xf7c34000 1052672 alloc_large_system_hash+0x144/0x1d9 pages=256 vmalloc N0=256
    0xf7c39000-0xf7cba000 528384 alloc_large_system_hash+0x144/0x1d9 pages=128 vmalloc N0=128
    0xf7cbb000-0xf7cc0000 20480 alloc_large_system_hash+0x144/0x1d9 pages=4 vmalloc N0=4
    0xf7cc1000-0xf7cc6000 20480 alloc_large_system_hash+0x144/0x1d9 pages=4 vmalloc N0=4


    So I tried following experiment :

    # swapoff
    # numactl --membind=0 swapon -a
    # grep swap /proc/vmallocinfo
    0xf9bf3000-0xf9cf4000 1052672 sys_swapon+0x4aa/0xb24 pages=256 vmalloc N0=256
    # swapoff -a
    # numactl --membind=1 swapon -a

    <<FREEZE>>


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