[-mm PATCH] Memory controller improve user interface (v2)

Balbir Singh
2007-08-30T18:53:10Z

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

Tested on a UML setup with the config for memory control enabled.

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

Documentation/controllers/memory.txt | 22 +++++++++++++-
include/linux/res_counter.h | 10 +++---
kernel/res_counter.c | 30 +++++++++++++------
mm/memcontrol.c | 53 ++++++++++++++++++++++++++++-------
4 files changed, 90 insertions(+), 25 deletions(-)

diff -puN mm/memcontrol.c~mem-control-make-ui-more-usable mm/memcontrol.c
--- linux-2.6.23-rc3/mm/memcontrol.c~mem-control-make-ui-more-usable 2007-08-29 16:18:39.000000000 +0530
+++ linux-2.6.23-rc3-balbir/mm/memcontrol.c 2007-08-31 00:09:51.000000000 +0530
@@ -312,7 +312,7 @@ 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, PAGE_SIZE)) {
if (try_to_free_mem_container_pages(mem))
continue;

@@ -352,7 +352,7 @@ 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, PAGE_SIZE);
css_put(&mem->css);
goto done;
}
@@ -417,7 +417,7 @@ 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, PAGE_SIZE);

spin_lock_irqsave(&mem->lru_lock, flags);
list_del_init(&pc->lru);
@@ -426,12 +426,44 @@ 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)
+/*
+ * Strategy routines for formating read/write data
+ */
+int mem_container_read_strategy(unsigned long long val, char *buf)
+{
+ return sprintf(buf, "%llu Bytes\n", val);
+}
+
+int mem_container_write_strategy(char *buf, unsigned long long *tmp)
+{
+ *tmp = memparse(buf, &buf);
+ if (*buf != '\0')
+ return -EINVAL;
+
+ printk("tmp is %llu\n", *tmp);
+ /*
+ * Round up the value to the closest page size
+ */
+ *tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT;
+ 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 +471,8 @@ 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 +533,13 @@ 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-more-usable include/linux/memcontrol.h
diff -puN include/linux/res_counter.h~mem-control-make-ui-more-usable include/linux/res_counter.h
--- linux-2.6.23-rc3/include/linux/res_counter.h~mem-control-make-ui-more-usable 2007-08-29 16:18:39.000000000 +0530
+++ linux-2.6.23-rc3-balbir/include/linux/res_counter.h 2007-08-30 23:48:49.000000000 +0530
@@ -23,11 +23,11 @@ struct res_counter {
/*
* the current resource consumption level
*/
- unsigned long usage;
+ unsigned long long usage;
/*
* the limit that usage cannot exceed
*/
- unsigned long limit;
+ unsigned long long limit;
/*
* the number of unsuccessful attempts to consume the resource
*/
@@ -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 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 long *val));

/*
* the field descriptors. one for each member of res_counter
diff -puN kernel/res_counter.c~mem-control-make-ui-more-usable kernel/res_counter.c
--- linux-2.6.23-rc3/kernel/res_counter.c~mem-control-make-ui-more-usable 2007-08-29 16:18:39.000000000 +0530
+++ linux-2.6.23-rc3-balbir/kernel/res_counter.c 2007-08-30 23:49:52.000000000 +0530
@@ -16,7 +16,7 @@
void res_counter_init(struct res_counter *counter)
{
spin_lock_init(&counter->lock);
- counter->limit = (unsigned long)LONG_MAX;
+ counter->limit = (unsigned long long)LLONG_MAX;
}

int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
@@ -76,24 +76,29 @@ 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 long val, char *st_buf))
{
- unsigned long *val;
+ unsigned long 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 long *val))
{
int ret;
char *buf, *end;
- unsigned long tmp, *val;
+ unsigned long long tmp, *val;

buf = kmalloc(nbytes + 1, GFP_KERNEL);
ret = -ENOMEM;
@@ -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-more-usable Documentation/controllers/memory.txt
--- linux-2.6.23-rc3/Documentation/controllers/memory.txt~mem-control-make-ui-more-usable 2007-08-29 16:18:39.000000000 +0530
+++ linux-2.6.23-rc3-balbir/Documentation/controllers/memory.txt 2007-08-31 00:19:31.000000000 +0530
@@ -165,11 +165,29 @@ 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 4M > /containers/0/memory.limit
+
+NOTE: We can use a suffix (k, K, m, M, g or G) to indicate values in kilo,
+mega or gigabytes.
+
+# cat /containers/0/memory.limit
+4194304 Bytes
+
+NOTE: The interface has now changed to display the usage in bytes
+instead of pages

We can check the usage:
# cat /containers/0/memory.usage
-25
+1216512 Bytes
+
+Setting a limit to a number that is not a multiple of page size causes
+rounding up of the value. The user must check back to see (by reading
+memory.limit), to check for differences between desired values and committed
+values. Currently, all accounting is done in multiples of PAGE_SIZE
+
+# echo -n 1 > memory.limit
+# cat memory.limit
+4096 Bytes

The memory.failcnt field gives the number of times that the container limit was
exceeded.
_

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