Hi Kame-san, On 03/26/2015 11:12 AM, Kamezawa Hiroyuki wrote:
> 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 ? wq generates the numa affinity (pool->node) for all the possible cpu's per cpu workqueue at init stage, that means the affinity of currently un-present ones' may be incorrect, so we need to update the pool->node for the new added cpu to the correct node when preparing online, otherwise it will try to create worker on invalid node if node hotplug occurred. Regards, Gu > > Thanks, > -Kame > >> >> arch/x86/kernel/apic/apic.c | 31 ++++++++++++++++++++++++++++++- >> kernel/workqueue.c | 1 + >> 2 files changed, 31 insertions(+), 1 deletions(-) >> > > > . > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
