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 far as I can tell loongsoon3 initially sets max_low_pfn in
node_mem_init(0) and then re-evaluates it in paging_init(). So it seems
that in this case the limit would be wrong for a system with more than one
node, but it would be set to some usable value.
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.
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().
> Fixes: bcec54bf3118 ("mips: switch to NO_BOOTMEM")
> Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@xxxxxxx>
> ---
> arch/mips/kernel/setup.c | 18 +++++++++---------
> arch/mips/loongson64/loongson-3/numa.c | 1 +
> arch/mips/sgi-ip27/ip27-memory.c | 1 +
> 3 files changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> index ea09ed6a80a9..b5167b198231 100644
> --- a/arch/mips/kernel/setup.c
> +++ b/arch/mips/kernel/setup.c
> @@ -576,6 +576,15 @@ static void __init bootmem_init(void)
> * Reserve initrd memory if needed.
> */
> finalize_initrd();
> +
> + /*
> + * Prevent memblock from allocating high memory.
> + * This cannot be done before max_low_pfn is detected, so up
> + * to this point is possible to only reserve physical memory
> + * with memblock_reserve; memblock_alloc* can be used
> + * only after this point
> + */
> + memblock_set_current_limit(PFN_PHYS(max_low_pfn));
> }
>
> #endif /* CONFIG_SGI_IP27 */
> @@ -854,15 +863,6 @@ static void __init arch_mem_init(char **cmdline_p)
>
> bootmem_init();
>
> - /*
> - * Prevent memblock from allocating high memory.
> - * This cannot be done before max_low_pfn is detected, so up
> - * to this point is possible to only reserve physical memory
> - * with memblock_reserve; memblock_alloc* can be used
> - * only after this point
> - */
> - memblock_set_current_limit(PFN_PHYS(max_low_pfn));
> -
> #ifdef CONFIG_PROC_VMCORE
> if (setup_elfcorehdr && setup_elfcorehdr_size) {
> printk(KERN_INFO "kdump reserved memory at %lx-%lx\n",
> diff --git a/arch/mips/loongson64/loongson-3/numa.c b/arch/mips/loongson64/loongson-3/numa.c
> index 622761878cd1..5593a8e3cd88 100644
> --- a/arch/mips/loongson64/loongson-3/numa.c
> +++ b/arch/mips/loongson64/loongson-3/numa.c
> @@ -265,6 +265,7 @@ void __init paging_init(void)
> zones_size[ZONE_DMA32] = MAX_DMA32_PFN;
> #endif
> zones_size[ZONE_NORMAL] = max_low_pfn;
> + memblock_set_current_limit(PFN_PHYS(max_low_pfn));
> free_area_init_nodes(zones_size);
> }
>
> diff --git a/arch/mips/sgi-ip27/ip27-memory.c b/arch/mips/sgi-ip27/ip27-memory.c
> index d8b8444d6795..0d0deeae1f47 100644
> --- a/arch/mips/sgi-ip27/ip27-memory.c
> +++ b/arch/mips/sgi-ip27/ip27-memory.c
> @@ -468,6 +468,7 @@ void __init paging_init(void)
> max_low_pfn = end_pfn;
> }
> zones_size[ZONE_NORMAL] = max_low_pfn;
> + memblock_set_current_limit(PFN_PHYS(max_low_pfn));
> free_area_init_nodes(zones_size);
> }
>
> --
> 2.13.7
>
--
Sincerely yours,
Mike.
