mm: remove the highmem zones' memmap in the highmem zone
Since 01cefaef40c4 ("mm: provide more accurate estimation
of pages occupied by memmap") allocate the pages from lowmem for the
highmem zones' memmap. So It is not need to reserver the memmap's for
the highmem.
A 2G DDR3 for the arm platform:
On node 0 totalpages: 524288
free_area_init_node: node 0, pgdat 80ccd380, node_mem_map 80d38000
DMA zone: 3568 pages used for memmap
DMA zone: 0 pages reserved
DMA zone: 456704 pages, LIFO batch:31
HighMem zone: 528 pages used for memmap
HighMem zone: 67584 pages, LIFO batch:15
On node 0 totalpages: 524288
free_area_init_node: node 0, pgdat 80cd6f40, node_mem_map 80d42000
DMA zone: 3568 pages used for memmap
DMA zone: 0 pages reserved
DMA zone: 456704 pages, LIFO batch:31
HighMem zone: 67584 pages, LIFO batch:15
Signed-off-by: Hongbo Zhong <hongbo.zhong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9d38708..fa974d8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4937,16 +4937,18 @@
* and per-cpu initialisations
*/
memmap_pages = calc_memmap_size(size, realsize);
- if (freesize >= memmap_pages) {
- freesize -= memmap_pages;
- if (memmap_pages)
- printk(KERN_DEBUG
- " %s zone: %lu pages used for memmap\n",
- zone_names[j], memmap_pages);
- } else
- printk(KERN_WARNING
- " %s zone: %lu pages exceeds freesize %lu\n",
- zone_names[j], memmap_pages, freesize);
+ if (!is_highmem_idx(j)) {
+ if (freesize >= memmap_pages) {
+ freesize -= memmap_pages;
+ if (memmap_pages)
+ printk(KERN_DEBUG
+ " %s zone: %lu pages used for memmap\n",
+ zone_names[j], memmap_pages);
+ } else
+ printk(KERN_WARNING
+ " %s zone: %lu pages exceeds freesize %lu\n",
+ zone_names[j], memmap_pages, freesize);
+ }
/* Account for reserved pages */
if (j == 0 && freesize > dma_reserve) {