* Chang S. Bae <chang.seok....@intel.com> wrote:
> The CPU and node number will be written, as early enough, > to the segment limit of per CPU data and TSC_AUX MSR entry. > The information has been retrieved by vgetcpu in user space > and will be also loaded from the paranoid entry, when > FSGSBASE enabled. > > The new setup function is named after the getcpu(2) system > call, and will be called during each CPU initialization > (before setting up IST). It makes a facility useful to both > the kernel and userspace unconditionally available much > sooner. > > The change brings a substantial code removal. The redundant > setting of the segment in entry/vdso/vma.c and hotplug > notifier are removed. The title and the changelog is totally unreadable, full of grammar errors which makes it actively misleading... A good changelog should explain not what it does, but _why_ it is done: x86/vdso: Initialize the CPU/node NR segment descriptor earlier Currently the CPU/node NR segment descriptor (GDT_ENTRY_CPU_NUMBER) is initialized relatively late during CPU init, from the vCPU code, which has a number of disadvantages, such as hotplug CPU notifiers and SMP cross-calls. Instead just initialize it much earlier, directly in cpu_init(). This reduces complexity and increases robustness. I've edited the changelog, but please keep this in mind for future submissions. I also made a number of other cleanups to the code, will push them out after some testing. Thanks, Ingo