[PATCH 07/32] mm: tag reseve pages

Peter Zijlstra
2008-10-02T13:05:11Z

[-- Attachment #1: page_alloc-reserve.patch --]
[-- Type: text/plain, Size: 1719 bytes --]

Tag pages allocated from the reserves with a non-zero page->reserve.
This allows us to distinguish and account reserve pages.

Since low-memory situations are transient, and unrelated the the actual
page (any page can be on the freelist when we run low), don't mark the
page in any permanent way - just pass along the information to the
allocatee.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
include/linux/mm_types.h | 1 +
mm/page_alloc.c | 4 +++-
2 files changed, 4 insertions(+), 1 deletion(-)

Index: linux-2.6/include/linux/mm_types.h
===================================================================
--- linux-2.6.orig/include/linux/mm_types.h
+++ linux-2.6/include/linux/mm_types.h
@@ -70,6 +70,7 @@ struct page {
union {
pgoff_t index; /* Our offset within mapping. */
void *freelist; /* SLUB: freelist req. slab lock */
+ int reserve; /* page_alloc: page is a reserve page */
};
struct list_head lru; /* Pageout list, eg. active_list
* protected by zone->lru_lock !
Index: linux-2.6/mm/page_alloc.c
===================================================================
--- linux-2.6.orig/mm/page_alloc.c
+++ linux-2.6/mm/page_alloc.c
@@ -1433,8 +1433,10 @@ zonelist_scan:
}

page = buffered_rmqueue(preferred_zone, zone, order, gfp_mask);
- if (page)
+ if (page) {
+ page->reserve = !!(alloc_flags & ALLOC_NO_WATERMARKS);
break;
+ }
this_zone_full:
if (NUMA_BUILD)
zlc_mark_zone_full(zonelist, z);