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[PATCHv10,0/3] enable nr_cpus for powerpc without re-ordering cpu number

Message ID 20231227023934.12299-1-kernelfans@gmail.com (mailing list archive)
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Series enable nr_cpus for powerpc without re-ordering cpu number | expand

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Pingfan Liu Dec. 27, 2023, 2:39 a.m. UTC 
From: Pingfan Liu <piliu@redhat.com>

This series addresses the nr_cpus issue for PowerPC without re-ordering
cpu number. To save the memory used by percpu area, it also limits the
possible cpu numbers by allowing hole in cpu_possible_mask.

Because the last cpu number will bigger than nr_cpu_ids in this way,
some pointer arrays indexed by cpu should be extended to hold the
pointer, e.g. paca_ptrs.

Please notice that this series still has some issue (some cpu can not be
brought up), but before I resolve it. Please share your thoughts about
it.

Thanks


Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Cc: Wen Xiong <wenxiong@us.ibm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Sourabh Jain <sourabhjain@linux.ibm.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: kexec@lists.infradead.org
To: linuxppc-dev@lists.ozlabs.org

Pingfan Liu (3):
  powerpc/kernel: Remove check on paca_ptrs_size
  powerpc/kernel: Extend arrays' size to make room for a hole in
    cpu_possible_mask
  powerpc/smp: Allow hole in paca_ptrs to accommodate boot_cpu

 arch/powerpc/include/asm/paca.h    |  2 ++
 arch/powerpc/include/asm/smp.h     |  1 +
 arch/powerpc/kernel/paca.c         | 24 +++++++-----------------
 arch/powerpc/kernel/prom.c         |  6 ++++++
 arch/powerpc/kernel/setup-common.c | 26 +++++++++++++++++++++-----
 arch/powerpc/kernel/smp.c          |  3 ++-
 6 files changed, 39 insertions(+), 23 deletions(-)