lkml.org 
[lkml]   [2008]   [May]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH][RFC] Add alloc_pages_exact() and free_pages_exact()
On Tue, 13 May 2008 16:26:46 -0500 Timur Tabi wrote:

> include/linux/gfp.h | 3 ++
> mm/page_alloc.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 56 insertions(+), 0 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index bdd5c43..2b685eb 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1736,6 +1736,59 @@ void free_pages(unsigned long addr, unsigned int order)
>
> EXPORT_SYMBOL(free_pages);

Hi Timur,

Please use kernel-doc notation/format for these functions as documented
in Documentation/kernel-doc-nano-HOWTO.txt. Ask me if you have
any questions/problems with it.

> +/**
> + * Allocate an exact number of pages of physically-contiguous memory.
> + *
> + * This function is similar to alloc_pages(), except that it allocates the
> + * minimum number of pages to satisfy the request. alloc_pages() can only
> + * allocate memory in power-of-two pages.
> + *
> + * This function is also limited by MAX_ORDER.
> + *
> + * Memory allocated by this function must be released by free_pages_exact().
> + */
> +void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
> +{
> + unsigned int order = get_order(size);
> + unsigned long addr;
> +
> + addr = __get_free_pages(gfp_mask, order);
> + if (addr) {
> + unsigned long alloc_end = addr + (PAGE_SIZE << order);
> + unsigned long used = addr + PAGE_ALIGN(size);
> +
> + split_page(virt_to_page(addr), order);
> + while (used < alloc_end) {
> + free_page(used);
> + used += PAGE_SIZE;
> + }
> + }
> +
> + return (void *)addr;
> +}
> +EXPORT_SYMBOL(alloc_pages_exact);
> +
> +/**
> + * Releases memory allocated via alloc_pages_exact()
> + *
> + * Release the memory allocated by a previous call to alloc_pages_exact.
> + *
> + * The first parameter must be the value returned by alloc_pages_exact(),
> + * and the 'size' parameter must be the same as was passed to
> + * alloc_pages_exact().
> + */
> +void free_pages_exact(void *virt, size_t size)
> +{
> + unsigned long addr = (unsigned long)virt;
> + unsigned long end = addr + PAGE_ALIGN(size);
> +
> + while (addr < end) {
> + free_page(addr);
> + addr += PAGE_SIZE;
> + }
> +}
> +EXPORT_SYMBOL(free_pages_exact);


---
~Randy


\
 
 \ /
  Last update: 2008-05-14 18:07    [W:0.034 / U:0.160 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site