[PATCH 8/8] Per-container pages reclamation

[Pavel Emelianov <xemul@openvz.org>]

Implement try_to_free_pages_in_container() to free the
pages in container that has run out of memory.

The scan_control->isolate_pages() function is set to
isolate_pages_in_container() that isolates the container
pages only. The exported __isolate_lru_page() call
makes things look simpler than in the previous version.

Includes fix from Balbir Singh <balbir@in.ibm.com>

Signed-off-by: Pavel Emelianov <xemul@openvz.org>

---

diff -upr linux-2.6.22-rc2-mm1.orig/mm/rss_container.c linux-2.6.22-rc2-mm1-0/mm/rss_container.c
--- linux-2.6.22-rc2-mm1.orig/mm/rss_container.c	2007-05-30 16:16:58.000000000 +0400
+++ linux-2.6.22-rc2-mm1-0/mm/rss_container.c	2007-05-30 16:13:09.000000000 +0400
@@ -135,6 +135,76 @@
 	spin_unlock(&rss->res.lock);
 }
 
+void container_rss_move_lists(struct page *pg, bool active)
+{
+	struct rss_container *rss;
+	struct page_container *pc;
+
+	if (!page_mapped(pg))
+		return;
+
+	pc = page_container(pg);
+	if (pc == NULL)
+		return;
+
+	rss = pc->cnt;
+
+	spin_lock(&rss->res.lock);
+	if (active)
+		list_move(&pc->list, &rss->active_list);
+	else
+		list_move(&pc->list, &rss->inactive_list);
+	spin_unlock(&rss->res.lock);
+}
+
+static unsigned long isolate_container_pages(unsigned long nr_to_scan,
+		struct list_head *src, struct list_head *dst,
+		unsigned long *scanned, struct zone *zone, int mode)
+{
+	unsigned long nr_taken = 0;
+	struct page *page;
+	struct page_container *pc;
+	unsigned long scan;
+	LIST_HEAD(pc_list);
+
+	for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) {
+		pc = list_entry(src->prev, struct page_container, list);
+		page = pc->page;
+		if (page_zone(page) != zone)
+			continue;
+
+		list_move(&pc->list, &pc_list);
+
+		if (__isolate_lru_page(page, mode) == 0) {
+			list_move(&page->lru, dst);
+			nr_taken++;
+		}
+	}
+
+	list_splice(&pc_list, src);
+
+	*scanned = scan;
+	return nr_taken;
+}
+
+unsigned long isolate_pages_in_container(unsigned long nr_to_scan,
+		struct list_head *dst, unsigned long *scanned,
+		int order, int mode, struct zone *zone,
+		struct rss_container *rss, int active)
+{
+	unsigned long ret;
+
+	spin_lock(&rss->res.lock);
+	if (active)
+		ret = isolate_container_pages(nr_to_scan, &rss->active_list,
+				dst, scanned, zone, mode);
+	else
+		ret = isolate_container_pages(nr_to_scan, &rss->inactive_list,
+				dst, scanned, zone, mode);
+	spin_unlock(&rss->res.lock);
+	return ret;
+}
+
 void container_rss_add(struct page_container *pc)
 {
 	struct page *pg;
diff -upr linux-2.6.22-rc2-mm1.orig/mm/swap.c linux-2.6.22-rc2-mm1-0/mm/swap.c
--- linux-2.6.22-rc2-mm1.orig/mm/swap.c	2007-05-30 12:32:36.000000000 +0400
+++ linux-2.6.22-rc2-mm1-0/mm/swap.c	2007-05-30 16:13:09.000000000 +0400
@@ -31,6 +31,7 @@
 #include <linux/cpu.h>
 #include <linux/notifier.h>
 #include <linux/init.h>
+#include <linux/rss_container.h>
 
 /* How many pages do we try to swap or page in/out together? */
 int page_cluster;
@@ -148,6 +149,7 @@ void fastcall activate_page(struct page 
 		SetPageActive(page);
 		add_page_to_active_list(zone, page);
 		__count_vm_event(PGACTIVATE);
+		container_rss_move_lists(page, 1);
 	}
 	spin_unlock_irq(&zone->lru_lock);
 }
diff -upr linux-2.6.22-rc2-mm1.orig/include/linux/rss_container.h linux-2.6.22-rc2-mm1-0/include/linux/rss_container.h
--- linux-2.6.22-rc2-mm1.orig/include/linux/rss_container.h	2007-05-30 16:16:58.000000000 +0400
+++ linux-2.6.22-rc2-mm1-0/include/linux/rss_container.h	2007-05-30 16:13:09.000000000 +0400
@@ -24,6 +24,11 @@
 void mm_init_container(struct mm_struct *mm, struct task_struct *tsk);
 void mm_free_container(struct mm_struct *mm);
 
+void container_rss_move_lists(struct page *pg, bool active);
+unsigned long isolate_pages_in_container(unsigned long nr_to_scan,
+		struct list_head *dst, unsigned long *scanned,
+		int order, int mode, struct zone *zone,
+		struct rss_container *, int active);
 static inline void init_page_container(struct page *page)
 {
 	page_container(page) = NULL;
@@ -64,5 +68,7 @@
 {
 }
 
+#define isolate_container_pages(nr, dst, scanned, rss, act, zone) ({ BUG(); 0;})
+#define container_rss_move_lists(pg, active) do { } while (0)
 #endif
 #endif
diff -upr linux-2.6.22-rc2-mm1.orig/mm/vmscan.c linux-2.6.22-rc2-mm1-0/mm/vmscan.c
--- linux-2.6.22-rc2-mm1.orig/mm/vmscan.c	2007-05-30 12:32:36.000000000 +0400
+++ linux-2.6.22-rc2-mm1-0/mm/vmscan.c	2007-05-30 16:13:09.000000000 +0400
@@ -983,6 +1005,7 @@ force_reclaim_mapped:
 		ClearPageActive(page);
 
 		list_move(&page->lru, &zone->inactive_list);
+		container_rss_move_lists(page, 0);
 		pgmoved++;
 		if (!pagevec_add(&pvec, page)) {
 			__mod_zone_page_state(zone, NR_INACTIVE, pgmoved);
@@ -1011,6 +1034,7 @@ force_reclaim_mapped:
 		SetPageLRU(page);
 		VM_BUG_ON(!PageActive(page));
 		list_move(&page->lru, &zone->active_list);
+		container_rss_move_lists(page, 1);
 		pgmoved++;
 		if (!pagevec_add(&pvec, page)) {
 			__mod_zone_page_state(zone, NR_ACTIVE, pgmoved);
@@ -1230,6 +1248,36 @@ out:
 	return ret;
 }
 
+#ifdef CONFIG_RSS_CONTAINER
+unsigned long try_to_free_pages_in_container(struct rss_container *cnt)
+{
+	struct scan_control sc = {
+		.gfp_mask = GFP_KERNEL,
+		.may_writepage = 1,
+		.swap_cluster_max = 1,
+		.may_swap = 1,
+		.swappiness = vm_swappiness,
+		.order = 0, /* in this case we wanted one page only */
+		.cnt = cnt,
+		.isolate_pages = isolate_pages_in_container,
+	};
+	int node;
+	struct zone **zones;
+
+	for_each_online_node(node) {
+#ifdef CONFIG_HIGHMEM
+		zones = NODE_DATA(node)->node_zonelists[ZONE_HIGHMEM].zones;
+		if (do_try_to_free_pages(zones, sc.gfp_mask, &sc))
+			return 1;
+#endif
+		zones = NODE_DATA(node)->node_zonelists[ZONE_NORMAL].zones;
+		if (do_try_to_free_pages(zones, sc.gfp_mask, &sc))
+			return 1;
+	}
+	return 0;
+}
+#endif
+
 unsigned long try_to_free_pages(struct zone **zones, int order, gfp_t gfp_mask)
 {
 	struct scan_control sc = {