On 2015/03/26 11:17, Gu Zheng wrote:
> Yasuaki Ishimatsu found that with node online/offline, cpu<->node
> relationship is established. Because workqueue uses a info which was
> established at boot time, but it may be changed by node hotpluging.
>
> Once pool->node points to a stale node, following allocation failure
> happens.
> ==
> SLUB: Unable to allocate memory on node 2 (gfp=0x80d0)
> cache: kmalloc-192, object size: 192, buffer size: 192, default
> order:
> 1, min order: 0
> node 0: slabs: 6172, objs: 259224, free: 245741
> node 1: slabs: 3261, objs: 136962, free: 127656
> ==
>
> As the apicid <--> node relationship is persistent, so the root cause is the
^^^^^^^
pxm.
> cpu-id <-> lapicid mapping is not persistent (because the currently
> implementation
> always choose the first free cpu id for the new added cpu), so if we can build
> persistent cpu-id <-> lapicid relationship, this problem will be fixed.
>
> Please refer to https://lkml.org/lkml/2015/2/27/145 for the previous
> discussion.
>
> Gu Zheng (2):
> x86/cpu hotplug: make lapicid <-> cpuid mapping persistent
> workqueue: update per cpu workqueue's numa affinity when cpu
> preparing online
why patch(2/2) required ?
Thanks,
-Kame
>
> arch/x86/kernel/apic/apic.c | 31 ++++++++++++++++++++++++++++++-
> kernel/workqueue.c | 1 +
> 2 files changed, 31 insertions(+), 1 deletions(-)
>
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