[patch 2/4] mm: Fix free_all_bootmem_core alignment check

Johannes Weiner
2008-04-30T17:53:43Z

[-- Attachment #1: mm-fix-free_all_bootmem_core-alignment-check.patch --]
[-- Type: text/plain, Size: 1993 bytes --]

The check for node_boot_start is bogus because we start freeing at the
corresponding pfn. So check if the pfn is properly aligned instead in
a more readable way and adjust the documentation.

Also remove an unneeded accounting variable.

Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
CC: Ingo Molnar <mingo@elte.hu>
---

Index: linux-2.6/mm/bootmem.c
===================================================================
--- linux-2.6.orig/mm/bootmem.c
+++ linux-2.6/mm/bootmem.c
@@ -376,7 +376,7 @@ static unsigned long __init free_all_boo
struct page *page;
unsigned long pfn;
bootmem_data_t *bdata = pgdat->bdata;
- unsigned long i, count, total = 0;
+ unsigned long i, count;
unsigned long idx;
unsigned long *map;
int gofast = 0;
@@ -388,10 +388,13 @@ static unsigned long __init free_all_boo
pfn = PFN_DOWN(bdata->node_boot_start);
idx = bdata->node_low_pfn - pfn;
map = bdata->node_bootmem_map;
- /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
- if (bdata->node_boot_start == 0 ||
- ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
+ /*
+ * Check if we are aligned to BITS_PER_LONG pages. If so, we might
+ * be able to free page orders of that size at once.
+ */
+ if (!(pfn & (BITS_PER_LONG-1)))
gofast = 1;
+
for (i = 0; i < idx; ) {
unsigned long v = ~map[i / BITS_PER_LONG];

@@ -419,23 +422,19 @@ static unsigned long __init free_all_boo
}
pfn += BITS_PER_LONG;
}
- total += count;

/*
* Now free the allocator bitmap itself, it's not
* needed anymore:
*/
page = virt_to_page(bdata->node_bootmem_map);
- count = 0;
idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT;
- for (i = 0; i < idx; i++, page++) {
+ for (i = 0; i < idx; i++, page++)
__free_pages_bootmem(page, 0);
- count++;
- }
- total += count;
+ count += i;
bdata->node_bootmem_map = NULL;

- return total;
+ return count;
}

unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,

--