Re: [PATCH 06/10] bootmem: refactor free_all_bootmem_core

Ingo Molnar
2009-10-28T07:37:26Z

* FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> wrote:

> From: Chris Wright <chrisw@sous-sol.org>
>
> Move the loop that frees all bootmem pages back to page allocator into
> its own function. This should have not functional effect and allows the
> function to be reused later.
>
> Reviewed-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
> ---
> mm/bootmem.c | 61 +++++++++++++++++++++++++++++++++++++++-------------------
> 1 files changed, 41 insertions(+), 20 deletions(-)
>
> diff --git a/mm/bootmem.c b/mm/bootmem.c
> index 555d5d2..94ef2e7 100644
> --- a/mm/bootmem.c
> +++ b/mm/bootmem.c
> @@ -143,17 +143,22 @@ unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
> return init_bootmem_core(NODE_DATA(0)->bdata, start, 0, pages);
> }
>
> -static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
> +/**
> + * free_bootmem_pages - frees bootmem pages to page allocator
> + * @start: start pfn
> + * @end: end pfn
> + * @map: bootmem bitmap of reserved pages
> + *
> + * This will free the pages in the range @start to @end, making them
> + * available to the page allocator. The @map will be used to skip
> + * reserved pages. Returns the count of pages freed.
> + */
> +static unsigned long __init free_bootmem_pages(unsigned long start,
> + unsigned long end,
> + unsigned long *map)
> {
> + unsigned long cursor, count = 0;
> int aligned;
> - struct page *page;
> - unsigned long start, end, pages, count = 0;
> -
> - if (!bdata->node_bootmem_map)
> - return 0;
> -
> - start = bdata->node_min_pfn;
> - end = bdata->node_low_pfn;
>
> /*
> * If the start is aligned to the machines wordsize, we might
> @@ -161,27 +166,25 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
> */
> aligned = !(start & (BITS_PER_LONG - 1));
>
> - bdebug("nid=%td start=%lx end=%lx aligned=%d\n",
> - bdata - bootmem_node_data, start, end, aligned);
> + for (cursor = start; cursor < end; cursor += BITS_PER_LONG) {
> + unsigned long idx, vec;
>
> - while (start < end) {
> - unsigned long *map, idx, vec;
> -
> - map = bdata->node_bootmem_map;
> - idx = start - bdata->node_min_pfn;
> + idx = cursor - start;
> vec = ~map[idx / BITS_PER_LONG];
>
> - if (aligned && vec == ~0UL && start + BITS_PER_LONG < end) {
> + if (aligned && vec == ~0UL && cursor + BITS_PER_LONG < end) {
> int order = ilog2(BITS_PER_LONG);
>
> - __free_pages_bootmem(pfn_to_page(start), order);
> + __free_pages_bootmem(pfn_to_page(cursor), order);
> count += BITS_PER_LONG;
> } else {
> unsigned long off = 0;
>
> while (vec && off < BITS_PER_LONG) {
> if (vec & 1) {
> - page = pfn_to_page(start + off);
> + struct page *page;
> +
> + page = pfn_to_page(cursor + off);
> __free_pages_bootmem(page, 0);
> count++;
> }
> @@ -189,8 +192,26 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
> off++;
> }
> }
> - start += BITS_PER_LONG;
> }
> + return count;
> +}
> +
> +static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
> +{
> + struct page *page;
> + unsigned long start, end, *map, pages, count = 0;
> +
> + if (!bdata->node_bootmem_map)
> + return 0;
> +
> + start = bdata->node_min_pfn;
> + end = bdata->node_low_pfn;
> + map = bdata->node_bootmem_map;
> +
> + bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data,
> + start, end);
> +
> + count = free_bootmem_pages(start, end, map);
>
> page = virt_to_page(bdata->node_bootmem_map);
> pages = bdata->node_low_pfn - bdata->node_min_pfn;

Small nit: the initialization of count to 0 seems superfluous.

Ingo