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authorHui Wang <john.wanghui@huawei.com>2018-11-07 05:36:43 +0300
committerThomas Gleixner <tglx@linutronix.de>2018-12-18 15:38:37 +0300
commitaa02ef099cff042c2a9109782ec2bf1bffc955d4 (patch)
tree1ad972b32252d59b259d75652bfc8c8e7e339789 /arch/x86/kernel/kprobes/opt.c
parent438cbf8871246606f2fc1964d301fa02af39e4e4 (diff)
downloadlinux-aa02ef099cff042c2a9109782ec2bf1bffc955d4.tar.xz
x86/topology: Use total_cpus for max logical packages calculation
nr_cpu_ids can be limited on the command line via nr_cpus=. This can break the logical package management because it results in a smaller number of packages while in kdump kernel. Check below case: There is a two sockets system, each socket has 8 cores, which has 16 logical cpus while HT was turn on. 0 1 2 3 4 5 6 7 | 16 17 18 19 20 21 22 23 cores on socket 0 threads on socket 0 8 9 10 11 12 13 14 15 | 24 25 26 27 28 29 30 31 cores on socket 1 threads on socket 1 While starting the kdump kernel with command line option nr_cpus=16 panic was triggered on one of the cpus 24-31 eg. 26, then online cpu will be 1-15, 26(cpu 0 was disabled in kdump), ncpus will be 16 and __max_logical_packages will be 1, but actually two packages were booted on. This issue can reproduced by set kdump option nr_cpus=<real physical core numbers>, and then trigger panic on last socket's thread, for example: taskset -c 26 echo c > /proc/sysrq-trigger Use total_cpus which will not be limited by nr_cpus command line to calculate the value of __max_logical_packages. Signed-off-by: Hui Wang <john.wanghui@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: <guijianfeng@huawei.com> Cc: <wencongyang2@huawei.com> Cc: <douliyang1@huawei.com> Cc: <qiaonuohan@huawei.com> Link: https://lkml.kernel.org/r/20181107023643.22174-1-john.wanghui@huawei.com
Diffstat (limited to 'arch/x86/kernel/kprobes/opt.c')
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