[patch -rss] Make RSS accounting display more user friendly

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

Display the current usage and limit in a more user friendly manner. Number
of pages can be confusing if the page size is different. Some systems
can choose a page size of 64KB.

NOTE: Values shown in MB and GB could be rounded off.

Sample display

:~ # cat /container/rss_limit 
17179869183 (GB), 9223372036854775807 pages
:~ # cat /container/rss_usage 
36 (MB), 9220 pages
:~ # 

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

 include/linux/res_counter.h |    6 ++++++
 kernel/res_counter.c        |   27 +++++++++++++++++++++++----
 2 files changed, 29 insertions(+), 4 deletions(-)

diff -puN kernel/res_counter.c~rss-ui-display-kdb kernel/res_counter.c
--- linux-2.6.22-rc24-mm2/kernel/res_counter.c~rss-ui-display-kdb	2007-06-20 20:15:46.000000000 +0530
+++ linux-2.6.22-rc24-mm2-balbir/kernel/res_counter.c	2007-06-20 21:12:29.000000000 +0530
@@ -61,7 +61,8 @@ void res_counter_uncharge(struct res_cou
 }
 
 
-static inline unsigned long *res_counter_member(struct res_counter *cnt, int member)
+static inline unsigned long *res_counter_member(struct res_counter *cnt,
+						int member, int *format_mem)
 {
 	switch (member) {
 	case RES_USAGE:
@@ -69,6 +70,7 @@ static inline unsigned long *res_counter
 	case RES_LIMIT:
 		return &cnt->limit;
 	case RES_FAILCNT:
+		*format_mem = 0;
 		return &cnt->failcnt;
 	};
 
@@ -81,10 +83,26 @@ ssize_t res_counter_read(struct res_coun
 {
 	unsigned long *val;
 	char buf[64], *s;
+	int format_mem = 1;
+	unsigned long val_kb = 0, val_mb = 0, val_gb = 0;
 
 	s = buf;
-	val = res_counter_member(cnt, member);
-	s += sprintf(s, "%lu\n", *val);
+	val = res_counter_member(cnt, member, &format_mem);
+	/*
+	 * NOTE: GB and MB values might be rounded off
+	 */
+	if (format_mem) {
+		val_gb = (*val << PAGE_SHIFT) >> GB_SHIFT;
+		val_mb = (*val << PAGE_SHIFT) >> MB_SHIFT;
+		val_kb = (*val << PAGE_SHIFT) >> KB_SHIFT;
+		if (val_gb)
+			s += sprintf(s, "%lu (GB), %lu pages\n", val_gb, *val);
+		else if (val_mb)
+			s += sprintf(s, "%lu (MB), %lu pages\n", val_mb, *val);
+		else
+			s += sprintf(s, "%lu (KB), %lu pages\n", val_kb, *val);
+	} else
+		s += sprintf(s, "%lu\n", *val);
 	return simple_read_from_buffer((void __user *)userbuf, nbytes,
 			pos, buf, s - buf);
 }
@@ -95,6 +113,7 @@ ssize_t res_counter_write(struct res_cou
 	int ret;
 	char *buf, *end;
 	unsigned long tmp, *val;
+	int nop;
 
 	buf = kmalloc(nbytes + 1, GFP_KERNEL);
 	ret = -ENOMEM;
@@ -111,7 +130,7 @@ ssize_t res_counter_write(struct res_cou
 	if (*end != '\0')
 		goto out_free;
 
-	val = res_counter_member(cnt, member);
+	val = res_counter_member(cnt, member, &nop);
 	*val = tmp;
 	ret = nbytes;
 out_free:
diff -puN include/linux/res_counter.h~rss-ui-display-kdb include/linux/res_counter.h
--- linux-2.6.22-rc24-mm2/include/linux/res_counter.h~rss-ui-display-kdb	2007-06-20 20:15:46.000000000 +0530
+++ linux-2.6.22-rc24-mm2-balbir/include/linux/res_counter.h	2007-06-20 21:01:57.000000000 +0530
@@ -13,6 +13,12 @@
 
 #include <linux/container.h>
 
+#ifndef KB_SHIFT
+#define KB_SHIFT	10
+#define MB_SHIFT	20
+#define GB_SHIFT	30
+#endif
+
 /*
  * the core object. the container that wishes to account for some
  * resource may include this counter into its structures and use
_

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