On Wed, 14 Aug 2013 22:46:29 -0700 Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> Current early_pfn_to_nid() on arch that support memblock go
> over memblock.memory one by one, so will take too many try
> near the end.
>
> We can use existing memblock_search to find the node id for
> given pfn, that could save some time on bigger system that
> have many entries memblock.memory array.
Looks nice. I wonder how much difference it makes.
> ...
>
> --- linux-2.6.orig/include/linux/memblock.h
> +++ linux-2.6/include/linux/memblock.h
> @@ -60,6 +60,8 @@ int memblock_reserve(phys_addr_t base, p
> void memblock_trim_memory(phys_addr_t align);
>
> #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
> +int memblock_search_pfn_nid(unsigned long pfn, unsigned long *start_pfn,
> + unsigned long *end_pfn);
> void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn,
> unsigned long *out_end_pfn, int *out_nid);
>
> Index: linux-2.6/mm/memblock.c
> ===================================================================
> --- linux-2.6.orig/mm/memblock.c
> +++ linux-2.6/mm/memblock.c
> @@ -914,6 +914,24 @@ int __init_memblock memblock_is_memory(p
> return memblock_search(&memblock.memory, addr) != -1;
> }
>
> +#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
> +int __init_memblock memblock_search_pfn_nid(unsigned long pfn,
> + unsigned long *start_pfn, unsigned long *end_pfn)
> +{
> + struct memblock_type *type = &memblock.memory;
> + int mid = memblock_search(type, (phys_addr_t)pfn << PAGE_SHIFT);
> +
> + if (mid == -1)
> + return -1;
> +
> + *start_pfn = type->regions[mid].base >> PAGE_SHIFT;
> + *end_pfn = (type->regions[mid].base + type->regions[mid].size)
> + >> PAGE_SHIFT;
> +
> + return type->regions[mid].nid;
> +}
> +#endif
This function will have no callers if
CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID=y. That's not too bad as the
function is __init_memblock. But this depends on
CONFIG_ARCH_DISCARD_MEMBLOCK. Messy :(
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