The foreach_order_pgoff() helper takes advantage of the ability to insert multi-order entries into a radix. It is currently used by devm_memremap_pages() to minimize the number of entries in the pgmap radix. Instead of dividing a range by a constant power-of-2 sized unit and inserting an entry for each unit, it determines the maximum power-of-2 sized entry (subject to alignment offset) that can be inserted at each iteration.
Up-level this helper so it can be used for populating other radix instances. For example asynchronous-memmap-initialization-thread lookups arriving in a follow on change. Cc: Logan Gunthorpe <[email protected]> Cc: Matthew Wilcox <[email protected]> Signed-off-by: Dan Williams <[email protected]> --- include/linux/memremap.h | 25 +++++++++++++++++++++++++ kernel/memremap.c | 25 ------------------------- 2 files changed, 25 insertions(+), 25 deletions(-) diff --git a/include/linux/memremap.h b/include/linux/memremap.h index bfdc7363b13b..bff314de3f55 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -126,6 +126,31 @@ struct dev_pagemap { enum memory_type type; }; +static inline unsigned long order_at(struct resource *res, unsigned long pgoff) +{ + unsigned long phys_pgoff = PHYS_PFN(res->start) + pgoff; + unsigned long nr_pages, mask; + + nr_pages = PHYS_PFN(resource_size(res)); + if (nr_pages == pgoff) + return ULONG_MAX; + + /* + * What is the largest aligned power-of-2 range available from + * this resource pgoff to the end of the resource range, + * considering the alignment of the current pgoff? + */ + mask = phys_pgoff | rounddown_pow_of_two(nr_pages - pgoff); + if (!mask) + return ULONG_MAX; + + return find_first_bit(&mask, BITS_PER_LONG); +} + +#define foreach_order_pgoff(res, order, pgoff) \ + for (pgoff = 0, order = order_at((res), pgoff); order < ULONG_MAX; \ + pgoff += 1UL << order, order = order_at((res), pgoff)) + #ifdef CONFIG_ZONE_DEVICE void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap, void (*kill)(struct percpu_ref *)); diff --git a/kernel/memremap.c b/kernel/memremap.c index 85e4a7c576b2..fc2f28033460 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -16,31 +16,6 @@ static RADIX_TREE(pgmap_radix, GFP_KERNEL); #define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1) #define SECTION_SIZE (1UL << PA_SECTION_SHIFT) -static unsigned long order_at(struct resource *res, unsigned long pgoff) -{ - unsigned long phys_pgoff = PHYS_PFN(res->start) + pgoff; - unsigned long nr_pages, mask; - - nr_pages = PHYS_PFN(resource_size(res)); - if (nr_pages == pgoff) - return ULONG_MAX; - - /* - * What is the largest aligned power-of-2 range available from - * this resource pgoff to the end of the resource range, - * considering the alignment of the current pgoff? - */ - mask = phys_pgoff | rounddown_pow_of_two(nr_pages - pgoff); - if (!mask) - return ULONG_MAX; - - return find_first_bit(&mask, BITS_PER_LONG); -} - -#define foreach_order_pgoff(res, order, pgoff) \ - for (pgoff = 0, order = order_at((res), pgoff); order < ULONG_MAX; \ - pgoff += 1UL << order, order = order_at((res), pgoff)) - #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) int device_private_entry_fault(struct vm_area_struct *vma, unsigned long addr, _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
