Re: [[PATCH]] mips: Fix switch to NO_BOOTMEM for SGI-IP27/loongons3 NUMA

From: Thomas Bogendoerfer
Date: Thu Nov 08 2018 - 11:52:23 EST


On Thu, 8 Nov 2018 18:18:23 +0200
Mike Rapoport <rppt@xxxxxxxxxxxxx> wrote:

> On Thu, Nov 08, 2018 at 03:44:28PM +0100, Thomas Bogendoerfer wrote:
> > Commit bcec54bf3118 ("mips: switch to NO_BOOTMEM") broke SGI-IP27
> > and NUMA enabled loongson3 by doing memblock_set_current_limit()
> > before max_low_pfn has been evaluated. Both platforms need to do the
> > memblock_set_current_limit() in platform specific code. For
> > consistency the call to memblock_set_current_limit() is moved
> > to the common bootmem_init(), where max_low_pfn is calculated
> > for non NUMA enabled platforms.
> [..]
>
> As for SGI-IP27, the initialization of max_low_pfn as late as in
> paging_init() seems to be broken because it's value is used in
> arch_mem_init() and in finalize_initrd() anyway.

well, the patch is tested on real hardware and the first caller of
a memblock_alloc* function is in a function called by free_area_init_nodes().

> AFAIU, both platforms set max_low_pfn to last available pfn, so it seems we
> can simply do
>
> max_low_pfn = PFN_PHYS(memblock_end_of_DRAM())
>
> in the prom_meminit() function for both platforms and drop the loop
> evaluating max_low_pfn in paging_init().

sounds like a better plan. I'll prepare a new patch.

Thomas.

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