[PATCH -mm 05/14] bootmem: revisit bitmap size calculations

Johannes Weiner
2008-05-30T19:42:25Z

[-- Attachment #1: bootmem-revisit-bitmap-size-calculation.patch --]
[-- Type: text/plain, Size: 2564 bytes --]

Reincarnate get_mapsize as bootmap_bytes and implement
bootmem_bootmap_pages on top of it.

Adjust users of these helpers and make free_all_bootmem_core use
bootmem_bootmap_pages instead of open-coding it.

Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
---

mm/bootmem.c | 27 +++++++++------------------
1 file changed, 9 insertions(+), 18 deletions(-)

--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -50,17 +50,11 @@ early_param("bootmem_debug", bootmem_deb
__FUNCTION__, ## args); \
})

-/*
- * Given an initialised bdata, it returns the size of the boot bitmap
- */
-static unsigned long __init get_mapsize(bootmem_data_t *bdata)
+static unsigned long __init bootmap_bytes(unsigned long pages)
{
- unsigned long mapsize;
- unsigned long start = PFN_DOWN(bdata->node_boot_start);
- unsigned long end = bdata->node_low_pfn;
+ unsigned long bytes = (pages + 7) / 8;

- mapsize = ((end - start) + 7) / 8;
- return ALIGN(mapsize, sizeof(long));
+ return ALIGN(bytes, sizeof(long));
}

/**
@@ -69,13 +63,9 @@ static unsigned long __init get_mapsize(
*/
unsigned long __init bootmem_bootmap_pages(unsigned long pages)
{
- unsigned long mapsize;
-
- mapsize = (pages+7)/8;
- mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
- mapsize >>= PAGE_SHIFT;
+ unsigned long bytes = bootmap_bytes(pages);

- return mapsize;
+ return PAGE_ALIGN(bytes) >> PAGE_SHIFT;
}

/*
@@ -117,7 +107,7 @@ static unsigned long __init init_bootmem
* Initially all pages are reserved - setup_arch() has to
* register free RAM areas explicitly.
*/
- mapsize = get_mapsize(bdata);
+ mapsize = bootmap_bytes(end - start);
memset(bdata->node_bootmem_map, 0xff, mapsize);

bdebug("nid=%d start=%lx map=%lx end=%lx mapsize=%ld\n",
@@ -160,7 +150,7 @@ static unsigned long __init free_all_boo
struct page *page;
unsigned long pfn;
unsigned long i, count;
- unsigned long idx;
+ unsigned long idx, pages;
unsigned long *map;
int gofast = 0;

@@ -211,7 +201,8 @@ static unsigned long __init free_all_boo
* needed anymore:
*/
page = virt_to_page(bdata->node_bootmem_map);
- idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT;
+ pages = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
+ idx = bootmem_bootmap_pages(pages);
for (i = 0; i < idx; i++, page++)
__free_pages_bootmem(page, 0);
count += i;