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.
ChangeLog:
v5: add out of trouble notify to exit of balance_pgdat().
Signed-off-by: Marcelo Tosatti <[EMAIL PROTECTED]>
Signed-off-by: KOSAKI Motohiro <[EMAIL PROTECTED]>
---
mm/page_alloc.c | 12 ++++++++++++
mm/vmscan.c | 26 ++++++++++++++++++++++++++
2 files changed, 38 insertions(+)
Index: b/mm/vmscan.c
===================================================================
--- a/mm/vmscan.c 2008-01-23 22:06:08.000000000 +0900
+++ b/mm/vmscan.c 2008-01-23 22:07:57.000000000 +0900
@@ -39,6 +39,7 @@
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/memcontrol.h>
+#include <linux/mem_notify.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
@@ -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)) {
@@ -1659,6 +1677,14 @@ out:
goto loop_again;
}
+ for (i = pgdat->nr_zones - 1; i >= 0; i--) {
+ struct zone *zone = pgdat->node_zones + i;
+
+ if (!populated_zone(zone))
+ continue;
+ memory_pressure_notify(zone, 0);
+ }
+
return nr_reclaimed;
}
Index: b/mm/page_alloc.c
===================================================================
--- a/mm/page_alloc.c 2008-01-23 22:06:08.000000000 +0900
+++ b/mm/page_alloc.c 2008-01-23 23:09:32.000000000 +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 +469,14 @@ 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((zone->mem_notify_status == 1) &&
+ (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)
--
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