the notification point to happen whenever the VM moves an
anonymous page to the inactive list - this is a pretty good indication
that there are unused anonymous pages present which will be very likely
swapped out soon.
and, It is judged out of trouble at the fllowing situations.
o memory pressure decrease and stop moves an anonymous page to the inactive list.
o free pages increase than (pages_high+lowmem_reserve)*2.
Signed-off-by: Marcelo Tosatti <marcelo@kvack.org>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
mm/vmscan.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
Index: linux-2.6.24-rc6-mm1-memnotify/mm/vmscan.c
===================================================================
--- linux-2.6.24-rc6-mm1-memnotify.orig/mm/vmscan.c 2008-01-13 16:59:28.000000000 +0900
+++ linux-2.6.24-rc6-mm1-memnotify/mm/vmscan.c 2008-01-13 17:03:58.000000000 +0900
@@ -963,6 +963,7 @@ static int calc_reclaim_mapped(struct sc
long distress;
long swap_tendency;
long imbalance;
+ int reclaim_mapped = 0;
int prev_priority;
if (scan_global_lru(sc) && zone_is_near_oom(zone))
@@ -1089,10 +1090,14 @@ static void shrink_active_list(unsigned
struct page *page;
struct pagevec pvec;
int reclaim_mapped = 0;
+ bool inactivated_anon = 0;
if (sc->may_swap)
reclaim_mapped = calc_reclaim_mapped(sc, zone, priority);
+ if (!reclaim_mapped)
+ memory_pressure_notify(zone, 0);
+
lru_add_drain();
spin_lock_irq(&zone->lru_lock);
pgmoved = sc->isolate_pages(nr_pages, &l_hold, &pgscanned, sc->order,
@@ -1116,6 +1121,13 @@ static void shrink_active_list(unsigned
if (!reclaim_mapped ||
(total_swap_pages == 0 && PageAnon(page)) ||
page_referenced(page, 0, sc->mem_cgroup)) {
+ /* deal with the case where there is no
+ * swap but an anonymous page would be
+ * moved to the inactive list.
+ */
+ if (!total_swap_pages && reclaim_mapped &&
+ PageAnon(page))
+ inactivated_anon = 1;
list_add(&page->lru, &l_active);
continue;
}
@@ -1123,8 +1135,12 @@ static void shrink_active_list(unsigned
list_add(&page->lru, &l_active);
continue;
}
+ if (PageAnon(page))
+ inactivated_anon = 1;
list_add(&page->lru, &l_inactive);
}
+ if (inactivated_anon)
+ memory_pressure_notify(zone, 1);
pagevec_init(&pvec, 1);
pgmoved = 0;
@@ -1158,6 +1174,8 @@ static void shrink_active_list(unsigned
pagevec_strip(&pvec);
spin_lock_irq(&zone->lru_lock);
}
+ if (!reclaim_mapped)
+ memory_pressure_notify(zone, 0);
pgmoved = 0;
while (!list_empty(&l_active)) {
Index: linux-2.6.24-rc6-mm1-memnotify/mm/page_alloc.c
===================================================================
--- linux-2.6.24-rc6-mm1-memnotify.orig/mm/page_alloc.c 2008-01-13 16:57:10.000000000 +0900
+++ linux-2.6.24-rc6-mm1-memnotify/mm/page_alloc.c 2008-01-13 17:04:34.000000000 +0900
@@ -44,6 +44,7 @@
#include <linux/fault-inject.h>
#include <linux/page-isolation.h>
#include <linux/memcontrol.h>
+#include <linux/mem_notify.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
@@ -435,6 +436,8 @@ static inline void __free_one_page(struc
unsigned long page_idx;
int order_size = 1 << order;
int migratetype = get_pageblock_migratetype(page);
+ unsigned long prev_free;
+ unsigned long notify_threshold;
if (unlikely(PageCompound(page)))
destroy_compound_page(page, order);
@@ -444,6 +447,7 @@ static inline void __free_one_page(struc
VM_BUG_ON(page_idx & (order_size - 1));
VM_BUG_ON(bad_range(zone, page));
+ prev_free = zone_page_state(zone, NR_FREE_PAGES);
__mod_zone_page_state(zone, NR_FREE_PAGES, order_size);
while (order < MAX_ORDER-1) {
unsigned long combined_idx;
@@ -465,6 +469,13 @@ static inline void __free_one_page(struc
list_add(&page->lru,
&zone->free_area[order].free_list[migratetype]);
zone->free_area[order].nr_free++;
+
+ notify_threshold = (zone->pages_high +
+ zone->lowmem_reserve[MAX_NR_ZONES-1]) * 2;
+
+ if (unlikely((prev_free <= notify_threshold) &&
+ (zone_page_state(zone, NR_FREE_PAGES) > notify_threshold)))
+ memory_pressure_notify(zone, 0);
}
static inline int free_pages_check(struct page *page)
--
