60、Kernel Synchronization and Lock Debugging

xray4

于 2025-09-06 10:01:27 发布

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分类专栏：深入Linux内核编程文章标签： Kernel Synchronization Lock Debugging Per-CPU Variables

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Kernel Synchronization and Lock Debugging

1. Per - CPU Variables in the Kernel

1.1 Controlling Live CPUs at Runtime

In a virtual machine, if you have multiple CPUs but want only a subset to be “live” at runtime, you can pass the maxcpus=n parameter to the VM’s kernel at boot. You can check if this parameter is set by looking at /proc/cmdline . For example:

$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-5.4.0-llkd-dbg root=UUID=1c4<...> ro console=ttyS0,115200n8 console=tty0  quiet splash 3 maxcpus=2

Here, we can see that the maxcpus=2 parameter is set, meaning only two CPUs will be active at runtime.

1.2 Per - CPU Variable Usage in th

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