[-mm PATCH 8/8] Add switch to control what type of pages to limit (v2)

[Balbir Singh <balbir@linux.vnet.ibm.com>]

Choose if we want cached pages to be accounted or not. By default both
are accounted for. A new set of tunables are added.

echo -n 1 > mem_control_type

switches the accounting to account for only mapped pages

echo -n 2 > mem_control_type

switches the behaviour back


Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
---

 include/linux/memcontrol.h |    9 +++
 mm/filemap.c               |    2 
 mm/memcontrol.c            |  129 ++++++++++++++++++++++++++++++++++++++-------
 mm/swap_state.c            |    2 
 4 files changed, 122 insertions(+), 20 deletions(-)

diff -puN mm/memcontrol.c~mem-control-choose-rss-vs-rss-and-pagecache mm/memcontrol.c
--- linux-2.6.22-rc6/mm/memcontrol.c~mem-control-choose-rss-vs-rss-and-pagecache	2007-07-05 20:00:07.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/memcontrol.c	2007-07-05 20:09:40.000000000 -0700
@@ -22,6 +22,8 @@
 #include <linux/swap.h>
 #include <linux/spinlock.h>
 
+#include <asm/uaccess.h>
+
 struct container_subsys mem_container_subsys;
 
 /*
@@ -52,6 +54,7 @@ struct mem_container {
 	 * spin_lock to protect the per container LRU
 	 */
 	spinlock_t lru_lock;
+	unsigned long control_type;	/* control RSS or RSS+Pagecache */
 };
 
 /*
@@ -65,6 +68,14 @@ struct meta_page {
 	atomic_t ref_cnt;
 };
 
+enum {
+	MEM_CONTAINER_TYPE_UNSPEC = 0,
+	MEM_CONTAINER_TYPE_MAPPED,
+	MEM_CONTAINER_TYPE_ALL,
+	MEM_CONTAINER_TYPE_MAX,
+} mem_control_type;
+
+static struct mem_container init_mem_container;
 
 static inline struct mem_container *mem_container_from_cont(struct container
 								*cnt)
@@ -301,6 +312,22 @@ err:
 }
 
 /*
+ * See if the cached pages should be charged at all?
+ */
+int mem_container_cache_charge(struct page *page, struct mm_struct *mm)
+{
+	struct mem_container *mem;
+	if (!mm)
+		mm = &init_mm;
+
+	mem = rcu_dereference(mm->mem_container);
+	if (mem->control_type & MEM_CONTAINER_TYPE_ALL)
+		return mem_container_charge(page, mm);
+	else
+		return 0;
+}
+
+/*
  * Uncharging is always a welcome operation, we never complain, simply
  * uncharge.
  */
@@ -311,7 +338,9 @@ void mem_container_uncharge(struct meta_
 	unsigned long flags;
 
 	/*
-	 * This can happen for PAGE_ZERO
+	 * This can happen for PAGE_ZERO. This can also handle cases when
+	 * a page is not charged at all and we are switching between
+	 * handling the control_type.
 	 */
 	if (!mp)
 		return;
@@ -350,26 +379,59 @@ static ssize_t mem_container_write(struc
 				cft->private, userbuf, nbytes, ppos);
 }
 
-static struct cftype mem_container_usage = {
-	.name = "mem_usage",
-	.private = RES_USAGE,
-	.read = mem_container_read,
-};
+static ssize_t mem_control_type_write(struct container *cont,
+			struct cftype *cft, struct file *file,
+			const char __user *userbuf,
+			size_t nbytes, loff_t *pos)
+{
+	int ret;
+	char *buf, *end;
+	unsigned long tmp;
+	struct mem_container *mem;
 
-static struct cftype mem_container_limit = {
-	.name = "mem_limit",
-	.private = RES_LIMIT,
-	.write = mem_container_write,
-	.read = mem_container_read,
-};
+	mem = mem_container_from_cont(cont);
+	buf = kmalloc(nbytes + 1, GFP_KERNEL);
+	ret = -ENOMEM;
+	if (buf == NULL)
+		goto out;
 
-static struct cftype mem_container_failcnt = {
-	.name = "mem_failcnt",
-	.private = RES_FAILCNT,
-	.read = mem_container_read,
-};
+	buf[nbytes] = 0;
+	ret = -EFAULT;
+	if (copy_from_user(buf, userbuf, nbytes))
+		goto out_free;
+
+	ret = -EINVAL;
+	tmp = simple_strtoul(buf, &end, 10);
+	if (*end != '\0')
+		goto out_free;
+
+	if (tmp <= MEM_CONTAINER_TYPE_UNSPEC || tmp >= MEM_CONTAINER_TYPE_MAX)
+		goto out_free;
+
+	mem->control_type = tmp;
+	ret = nbytes;
+out_free:
+	kfree(buf);
+out:
+	return ret;
+}
 
-static struct mem_container init_mem_container;
+static ssize_t mem_control_type_read(struct container *cont,
+				struct cftype *cft,
+				struct file *file, char __user *userbuf,
+				size_t nbytes, loff_t *ppos)
+{
+	unsigned long val;
+	char buf[64], *s;
+	struct mem_container *mem;
+
+	mem = mem_container_from_cont(cont);
+	s = buf;
+	val = mem->control_type;
+	s += sprintf(s, "%lu\n", val);
+	return simple_read_from_buffer((void __user *)userbuf, nbytes,
+			ppos, buf, s - buf);
+}
 
 static int mem_container_create(struct container_subsys *ss,
 				struct container *cont)
@@ -392,9 +454,36 @@ static int mem_container_create(struct c
 	INIT_LIST_HEAD(&mem->active_list);
 	INIT_LIST_HEAD(&mem->inactive_list);
 	spin_lock_init(&mem->lru_lock);
+	mem->control_type = MEM_CONTAINER_TYPE_ALL;
 	return 0;
 }
 
+static struct cftype mem_container_usage = {
+	.name = "mem_usage",
+	.private = RES_USAGE,
+	.read = mem_container_read,
+};
+
+static struct cftype mem_container_limit = {
+	.name = "mem_limit",
+	.private = RES_LIMIT,
+	.write = mem_container_write,
+	.read = mem_container_read,
+};
+
+static struct cftype mem_container_control_type = {
+	.name = "mem_control_type",
+	.write = mem_control_type_write,
+	.read = mem_control_type_read,
+};
+
+static struct cftype mem_container_failcnt = {
+	.name = "mem_failcnt",
+	.private = RES_FAILCNT,
+	.read = mem_container_read,
+};
+
+
 static void mem_container_destroy(struct container_subsys *ss,
 				struct container *cont)
 {
@@ -418,6 +507,10 @@ static int mem_container_populate(struct
 	if (rc < 0)
 		goto err;
 
+	rc = container_add_file(cont, &mem_container_control_type);
+	if (rc < 0)
+		goto err;
+
 err:
 	return rc;
 }
diff -puN include/linux/memcontrol.h~mem-control-choose-rss-vs-rss-and-pagecache include/linux/memcontrol.h
--- linux-2.6.22-rc6/include/linux/memcontrol.h~mem-control-choose-rss-vs-rss-and-pagecache	2007-07-05 20:00:07.000000000 -0700
+++ linux-2.6.22-rc6-balbir/include/linux/memcontrol.h	2007-07-05 20:00:07.000000000 -0700
@@ -15,6 +15,8 @@
 #ifndef _LINUX_MEMCONTROL_H
 #define _LINUX_MEMCONTROL_H
 
+#include <linux/mm.h>
+
 struct mem_container;
 struct meta_page;
 
@@ -34,6 +36,7 @@ extern unsigned long mem_container_isola
 					struct mem_container *mem_cont,
 					int active);
 extern void mem_container_out_of_memory(struct mem_container *mem);
+extern int mem_container_cache_charge(struct page *page, struct mm_struct *mm);
 
 #else /* CONFIG_CONTAINER_MEM_CONT */
 static inline void mm_init_container(struct mm_struct *mm,
@@ -68,6 +71,12 @@ static inline void mem_container_move_li
 {
 }
 
+static inline int mem_container_cache_charge(struct page *page,
+						struct mm_struct *mm)
+{
+	return 0;
+}
+
 #endif /* CONFIG_CONTAINER_MEM_CONT */
 
 #endif /* _LINUX_MEMCONTROL_H */
diff -puN mm/swap_state.c~mem-control-choose-rss-vs-rss-and-pagecache mm/swap_state.c
--- linux-2.6.22-rc6/mm/swap_state.c~mem-control-choose-rss-vs-rss-and-pagecache	2007-07-05 20:00:07.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/swap_state.c	2007-07-05 20:00:07.000000000 -0700
@@ -81,7 +81,7 @@ static int __add_to_swap_cache(struct pa
 	error = radix_tree_preload(gfp_mask);
 	if (!error) {
 
-		error = mem_container_charge(page, current->mm);
+		error = mem_container_cache_charge(page, current->mm);
 		if (error)
 			goto out;
 
diff -puN mm/filemap.c~mem-control-choose-rss-vs-rss-and-pagecache mm/filemap.c
--- linux-2.6.22-rc6/mm/filemap.c~mem-control-choose-rss-vs-rss-and-pagecache	2007-07-05 20:00:07.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/filemap.c	2007-07-05 20:00:07.000000000 -0700
@@ -445,7 +445,7 @@ int add_to_page_cache(struct page *page,
 
 	if (error == 0) {
 
-		error = mem_container_charge(page, current->mm);
+		error = mem_container_cache_charge(page, current->mm);
 		if (error)
 			goto out;
 
_

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL
-
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