[-mm PATCH] Memory controller improve user interface

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

Change the interface to use kilobytes instead of pages. Page sizes can vary
across platforms and configurations. A new strategy routine has been added
to the resource counters infrastructure to format the data as desired.

Suggested by David Rientjes, Andrew Morton and Herbert Poetzl

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

 Documentation/controllers/memory.txt |    7 +++--
 include/linux/res_counter.h          |    6 ++--
 kernel/res_counter.c                 |   24 +++++++++++++----
 mm/memcontrol.c                      |   47 +++++++++++++++++++++++++++--------
 4 files changed, 64 insertions(+), 20 deletions(-)

diff -puN mm/memcontrol.c~mem-control-make-ui-use-kilobytes mm/memcontrol.c
--- linux-2.6.23-rc3/mm/memcontrol.c~mem-control-make-ui-use-kilobytes	2007-08-28 13:20:44.000000000 +0530
+++ linux-2.6.23-rc3-balbir/mm/memcontrol.c	2007-08-29 14:36:07.000000000 +0530
@@ -32,6 +32,7 @@
 
 struct container_subsys mem_container_subsys;
 static const int MEM_CONTAINER_RECLAIM_RETRIES = 5;
+static const int MEM_CONTAINER_CHARGE_KB = (PAGE_SIZE >> 10);
 
 /*
  * The memory controller data structure. The memory controller controls both
@@ -312,7 +313,7 @@ int mem_container_charge(struct page *pa
 	 * If we created the page_container, we should free it on exceeding
 	 * the container limit.
 	 */
-	while (res_counter_charge(&mem->res, 1)) {
+	while (res_counter_charge(&mem->res, MEM_CONTAINER_CHARGE_KB)) {
 		if (try_to_free_mem_container_pages(mem))
 			continue;
 
@@ -352,7 +353,7 @@ int mem_container_charge(struct page *pa
 		kfree(pc);
 		pc = race_pc;
 		atomic_inc(&pc->ref_cnt);
-		res_counter_uncharge(&mem->res, 1);
+		res_counter_uncharge(&mem->res, MEM_CONTAINER_CHARGE_KB);
 		css_put(&mem->css);
 		goto done;
 	}
@@ -417,7 +418,7 @@ void mem_container_uncharge(struct page_
 		css_put(&mem->css);
 		page_assign_page_container(page, NULL);
 		unlock_page_container(page);
-		res_counter_uncharge(&mem->res, 1);
+		res_counter_uncharge(&mem->res, MEM_CONTAINER_CHARGE_KB);
 
  		spin_lock_irqsave(&mem->lru_lock, flags);
  		list_del_init(&pc->lru);
@@ -426,12 +427,37 @@ void mem_container_uncharge(struct page_
 	}
 }
 
-static ssize_t mem_container_read(struct container *cont, struct cftype *cft,
-			struct file *file, char __user *userbuf, size_t nbytes,
-			loff_t *ppos)
+int mem_container_read_strategy(unsigned long val, char *buf)
+{
+	return sprintf(buf, "%lu (kB)\n", val);
+}
+
+int mem_container_write_strategy(char *buf, unsigned long *tmp)
+{
+	*tmp = memparse(buf, &buf);
+	if (*buf != '\0')
+		return -EINVAL;
+
+	*tmp = *tmp >> 10;		/* convert to kilobytes */
+	return 0;
+}
+
+static ssize_t mem_container_read_usage(struct container *cont,
+			struct cftype *cft, struct file *file,
+			char __user *userbuf, size_t nbytes, loff_t *ppos)
+{
+	return res_counter_read(&mem_container_from_cont(cont)->res,
+				cft->private, userbuf, nbytes, ppos,
+				mem_container_read_strategy);
+}
+
+static ssize_t mem_container_read(struct container *cont,
+			struct cftype *cft, struct file *file,
+			char __user *userbuf, size_t nbytes, loff_t *ppos)
 {
 	return res_counter_read(&mem_container_from_cont(cont)->res,
-				cft->private, userbuf, nbytes, ppos);
+				cft->private, userbuf, nbytes, ppos,
+				NULL);
 }
 
 static ssize_t mem_container_write(struct container *cont, struct cftype *cft,
@@ -439,7 +465,8 @@ static ssize_t mem_container_write(struc
 				size_t nbytes, loff_t *ppos)
 {
 	return res_counter_write(&mem_container_from_cont(cont)->res,
-				cft->private, userbuf, nbytes, ppos);
+				cft->private, userbuf, nbytes, ppos,
+				mem_container_write_strategy);
 }
 
 static ssize_t mem_control_type_write(struct container *cont,
@@ -500,13 +527,13 @@ static struct cftype mem_container_files
 	{
 		.name = "usage",
 		.private = RES_USAGE,
-		.read = mem_container_read,
+		.read = mem_container_read_usage,
 	},
 	{
 		.name = "limit",
 		.private = RES_LIMIT,
 		.write = mem_container_write,
-		.read = mem_container_read,
+		.read = mem_container_read_usage,
 	},
 	{
 		.name = "failcnt",
diff -puN include/linux/memcontrol.h~mem-control-make-ui-use-kilobytes include/linux/memcontrol.h
diff -puN include/linux/res_counter.h~mem-control-make-ui-use-kilobytes include/linux/res_counter.h
--- linux-2.6.23-rc3/include/linux/res_counter.h~mem-control-make-ui-use-kilobytes	2007-08-28 13:21:36.000000000 +0530
+++ linux-2.6.23-rc3-balbir/include/linux/res_counter.h	2007-08-29 00:52:45.000000000 +0530
@@ -52,9 +52,11 @@ struct res_counter {
  */
 
 ssize_t res_counter_read(struct res_counter *counter, int member,
-		const char __user *buf, size_t nbytes, loff_t *pos);
+		const char __user *buf, size_t nbytes, loff_t *pos,
+		int (*read_strategy)(unsigned long val, char *s));
 ssize_t res_counter_write(struct res_counter *counter, int member,
-		const char __user *buf, size_t nbytes, loff_t *pos);
+		const char __user *buf, size_t nbytes, loff_t *pos,
+		int (*write_strategy)(char *buf, unsigned long *val));
 
 /*
  * the field descriptors. one for each member of res_counter
diff -puN kernel/res_counter.c~mem-control-make-ui-use-kilobytes kernel/res_counter.c
--- linux-2.6.23-rc3/kernel/res_counter.c~mem-control-make-ui-use-kilobytes	2007-08-28 13:21:41.000000000 +0530
+++ linux-2.6.23-rc3-balbir/kernel/res_counter.c	2007-08-29 14:54:04.000000000 +0530
@@ -76,20 +76,25 @@ static inline unsigned long *res_counter
 }
 
 ssize_t res_counter_read(struct res_counter *counter, int member,
-		const char __user *userbuf, size_t nbytes, loff_t *pos)
+		const char __user *userbuf, size_t nbytes, loff_t *pos,
+		int (*read_strategy)(unsigned long val, char *st_buf))
 {
 	unsigned long *val;
 	char buf[64], *s;
 
 	s = buf;
 	val = res_counter_member(counter, member);
-	s += sprintf(s, "%lu\n", *val);
+	if (read_strategy)
+		s += read_strategy(*val, s);
+	else
+		s += sprintf(s, "%lu\n", *val);
 	return simple_read_from_buffer((void __user *)userbuf, nbytes,
 			pos, buf, s - buf);
 }
 
 ssize_t res_counter_write(struct res_counter *counter, int member,
-		const char __user *userbuf, size_t nbytes, loff_t *pos)
+		const char __user *userbuf, size_t nbytes, loff_t *pos,
+		int (*write_strategy)(char *st_buf, unsigned long *val))
 {
 	int ret;
 	char *buf, *end;
@@ -106,9 +111,16 @@ ssize_t res_counter_write(struct res_cou
 		goto out_free;
 
 	ret = -EINVAL;
-	tmp = simple_strtoul(buf, &end, 10);
-	if (*end != '\0')
-		goto out_free;
+
+	if (write_strategy) {
+		if (write_strategy(buf, &tmp)) {
+			goto out_free;
+		}
+	} else {
+		tmp = simple_strtoul(buf, &end, 10);
+		if (*end != '\0')
+			goto out_free;
+	}
 
 	val = res_counter_member(counter, member);
 	*val = tmp;
diff -puN Documentation/controllers/memory.txt~mem-control-make-ui-use-kilobytes Documentation/controllers/memory.txt
--- linux-2.6.23-rc3/Documentation/controllers/memory.txt~mem-control-make-ui-use-kilobytes	2007-08-29 14:42:03.000000000 +0530
+++ linux-2.6.23-rc3-balbir/Documentation/controllers/memory.txt	2007-08-29 14:50:42.000000000 +0530
@@ -165,11 +165,14 @@ c. Enable CONFIG_CONTAINER_MEM_CONT
 
 Since now we're in the 0 container,
 We can alter the memory limit:
-# echo -n 6000 > /containers/0/memory.limit
+# echo -n 4000K > /containers/0/memory.limit
+
+NOTE: The interface has now changed to display the usage in kilobytes
+instead of pages
 
 We can check the usage:
 # cat /containers/0/memory.usage
-25
+56 (kB)
 
 The memory.failcnt field gives the number of times that the container limit was
 exceeded.
_

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/