Re: [PATCH v3] arch/sparc: support NR_CPUS = 4096

From: David Miller
Date: Tue Jun 06 2017 - 16:42:09 EST


From: Jane Chu <jane.chu@xxxxxxxxxx>
Date: Tue, 6 Jun 2017 14:32:29 -0600

> Linux SPARC64 limits NR_CPUS to 4064 because init_cpu_send_mondo_info()
> only allocates a single page for NR_CPUS mondo entries. Thus we cannot
> use all 4096 CPUs on some SPARC platforms.
>
> To fix, allocate (2^order) pages where order is set according to the size
> of cpu_list for possible cpus. Since cpu_list_pa and cpu_mondo_block_pa
> are not used in asm code, there are no imm13 offsets from the base PA
> that will break because they can only reach one page.
>
> Orabug: 25505750
>
> Signed-off-by: Jane Chu <jane.chu@xxxxxxxxxx>
>
> Reviewed-by: Bob Picco <bob.picco@xxxxxxxxxx>
> Reviewed-by: Atish Patra <atish.patra@xxxxxxxxxx>

Looks a lot better, applied, thanks!