Re: [PATCH v2 3/6] sh: prefer memblock APIs returning virtual address

Sam Ravnborg
2018-12-03T16:11:12Z

Hi Mike.

On Mon, Dec 03, 2018 at 05:47:12PM +0200, Mike Rapoport wrote:
> Rather than use the memblock_alloc_base that returns a physical address and
> then convert this address to the virtual one, use appropriate memblock
> function that returns a virtual address.
>
> There is a small functional change in the allocation of then NODE_DATA().
> Instead of panicing if the local allocation failed, the non-local
> allocation attempt will be made.
>
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
> arch/sh/mm/init.c | 18 +++++-------------
> arch/sh/mm/numa.c | 5 ++---
> 2 files changed, 7 insertions(+), 16 deletions(-)
>
> diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
> index c8c13c77..3576b5f 100644
> --- a/arch/sh/mm/init.c
> +++ b/arch/sh/mm/init.c
> @@ -192,24 +192,16 @@ void __init page_table_range_init(unsigned long start, unsigned long end,
> void __init allocate_pgdat(unsigned int nid)
> {
> unsigned long start_pfn, end_pfn;
> -#ifdef CONFIG_NEED_MULTIPLE_NODES
> - unsigned long phys;
> -#endif
>
> get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
>
> #ifdef CONFIG_NEED_MULTIPLE_NODES
> - phys = __memblock_alloc_base(sizeof(struct pglist_data),
> - SMP_CACHE_BYTES, end_pfn << PAGE_SHIFT);
> - /* Retry with all of system memory */
> - if (!phys)
> - phys = __memblock_alloc_base(sizeof(struct pglist_data),
> - SMP_CACHE_BYTES, memblock_end_of_DRAM());
> - if (!phys)
> + NODE_DATA(nid) = memblock_alloc_try_nid_nopanic(
> + sizeof(struct pglist_data),
> + SMP_CACHE_BYTES, MEMBLOCK_LOW_LIMIT,
> + MEMBLOCK_ALLOC_ACCESSIBLE, nid);
> + if (!NODE_DATA(nid))
> panic("Can't allocate pgdat for node %d\n", nid);
> -
> - NODE_DATA(nid) = __va(phys);
> - memset(NODE_DATA(nid), 0, sizeof(struct pglist_data));
The new code will always assign NODE_DATA(nid), where the old
code only assigned NODE_DATA(nid) in the good case.
I dunno if this is an issue, just noticed the difference and
wanted to point it out.

Sam