From: Xiaotian Feng on
From 14f7823986429b8374d18e3f648cd84575296e03 Mon Sep 17 00:00:00 2001
From: Xiaotian Feng <dfeng(a)redhat.com>
Date: Mon, 12 Jul 2010 18:00:37 +0800
Subject: [PATCH 04/30] mm: tag reseve pages

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(a)chello.nl>
Signed-off-by: Suresh Jayaraman <sjayaraman(a)suse.de>
Signed-off-by: Xiaotian Feng <dfeng(a)redhat.com>
---
include/linux/mm_types.h | 1 +
mm/page_alloc.c | 4 +++-
2 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index b8bb9a6..a95a202 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -71,6 +71,7 @@ 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 !
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 72a6be5..b9989c5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1656,8 +1656,10 @@ zonelist_scan:
try_this_zone:
page = buffered_rmqueue(preferred_zone, zone, order,
gfp_mask, migratetype);
- if (page)
+ if (page) {
+ page->reserve = !!(alloc_flags & ALLOC_NO_WATERMARKS);
break;
+ }
this_zone_full:
if (NUMA_BUILD)
zlc_mark_zone_full(zonelist, z);
--
1.7.1.1

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