Since my last v4 [1], the code has undergone great changes. The paca[] array has been reorganized and indexed by paca_ptrs[], which dramatically decreases the memory consumption even if there are many unpresent cpus in the middle.
However, reordering the logical cpu numbers can further decrease the size of paca_ptrs[] in the kdump case. So I keep [2/4], which rotate-shifts the cpu's sequence number in the device tree to obtain the logical cpu id. Patch [3-4/4] make efforts to decrease the nr_cpus to be less than or equal to two. [1]: https://lore.kernel.org/linuxppc-dev/1520829790-14029-1-git-send-email-kernelf...@gmail.com/ --- v6 -> v7 Add [1/4], which fixes compilation error on PPC32 Cc: Michael Ellerman <m...@ellerman.id.au> Cc: Nicholas Piggin <npig...@gmail.com> Cc: Christophe Leroy <christophe.le...@csgroup.eu> Cc: Mahesh Salgaonkar <mah...@us.ibm.com> Cc: Wen Xiong <wenxi...@us.ibm.com> Cc: Baoquan He <b...@redhat.com> Cc: Ming Lei <ming....@redhat.com> Cc: ke...@lists.infradead.org To: linuxppc-dev@lists.ozlabs.org Pingfan Liu (4): powerpc/setup : Enable boot_cpu_hwid for PPC32 powerpc/setup: Loosen the mapping between cpu logical id and its seq in dt powerpc/setup: Handle the case when boot_cpuid greater than nr_cpus powerpc/setup: alloc extra paca_ptrs to hold boot_cpuid arch/powerpc/include/asm/smp.h | 2 +- arch/powerpc/kernel/paca.c | 10 +-- arch/powerpc/kernel/prom.c | 29 +++++--- arch/powerpc/kernel/setup-common.c | 108 +++++++++++++++++++++++------ 4 files changed, 114 insertions(+), 35 deletions(-) -- 2.31.1