Simplify the memory controller and resource counter I/O routines
This patch strips out some I/O boilerplate from resource counters and
the memory controller. It also adds locking to the resource counter
reads and writes, and forbids writes to the root memory cgroup's limit
file.
cgroup_write_uint() is extended to call memparse() rather than just
simple_strtoull()
Signed-off-by: Paul Menage <[EMAIL PROTECTED]>
---
include/linux/cgroup.h | 2
include/linux/res_counter.h | 13 +----
kernel/cgroup.c | 2
kernel/res_counter.c | 64 +++++----------------------
mm/memcontrol.c | 103 ++++++++++----------------------------------
5 files changed, 45 insertions(+), 139 deletions(-)
Index: container-2.6.23-rc8-mm2/include/linux/res_counter.h
===================================================================
--- container-2.6.23-rc8-mm2.orig/include/linux/res_counter.h
+++ container-2.6.23-rc8-mm2/include/linux/res_counter.h
@@ -46,17 +46,12 @@ struct res_counter {
*
* @counter: the counter in question
* @member: the field to work with (see RES_xxx below)
- * @buf: the buffer to opeate on,...
- * @nbytes: its size...
- * @pos: and the offset.
+ * @val: the value passed by the user (for write)
*/
-ssize_t res_counter_read(struct res_counter *counter, int member,
- 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,
- int (*write_strategy)(char *buf, unsigned long long *val));
+unsigned long long res_counter_read(struct res_counter *counter, int member);
+int res_counter_write(struct res_counter *counter, int member,
+ unsigned long long val);
/*
* the field descriptors. one for each member of res_counter
Index: container-2.6.23-rc8-mm2/kernel/res_counter.c
===================================================================
--- container-2.6.23-rc8-mm2.orig/kernel/res_counter.c
+++ container-2.6.23-rc8-mm2/kernel/res_counter.c
@@ -75,58 +75,22 @@ res_counter_member(struct res_counter *c
return NULL;
}
-ssize_t res_counter_read(struct res_counter *counter, int member,
- const char __user *userbuf, size_t nbytes, loff_t *pos,
- int (*read_strategy)(unsigned long long val, char *st_buf))
+unsigned long long res_counter_read(struct res_counter *counter, int member)
{
- unsigned long long *val;
- char buf[64], *s;
-
- s = buf;
- val = res_counter_member(counter, member);
- if (read_strategy)
- s += read_strategy(*val, s);
- else
- s += sprintf(s, "%llu\n", *val);
- return simple_read_from_buffer((void __user *)userbuf, nbytes,
- pos, buf, s - buf);
+ unsigned long long val;
+ unsigned long flags;
+ spin_lock_irqsave(&counter->lock, flags);
+ val = *res_counter_member(counter, member);
+ spin_unlock_irqrestore(&counter->lock, flags);
+ return val;
}
-ssize_t res_counter_write(struct res_counter *counter, int member,
- const char __user *userbuf, size_t nbytes, loff_t *pos,
- int (*write_strategy)(char *st_buf, unsigned long long *val))
+int res_counter_write(struct res_counter *counter, int member,
+ unsigned long long val)
{
- int ret;
- char *buf, *end;
- unsigned long long tmp, *val;
-
- buf = kmalloc(nbytes + 1, GFP_KERNEL);
- ret = -ENOMEM;
- if (buf == NULL)
- goto out;
-
- buf[nbytes] = '\0';
- ret = -EFAULT;
- if (copy_from_user(buf, userbuf, nbytes))
- goto out_free;
-
- ret = -EINVAL;
-
- if (write_strategy) {
- if (write_strategy(buf, &tmp)) {
- goto out_free;
- }
- } else {
- tmp = simple_strtoull(buf, &end, 10);
- if (*end != '\0')
- goto out_free;
- }
-
- val = res_counter_member(counter, member);
- *val = tmp;
- ret = nbytes;
-out_free:
- kfree(buf);
-out:
- return ret;
+ unsigned long flags;
+ spin_lock_irqsave(&counter->lock, flags);
+ *res_counter_member(counter, member) = val;
+ spin_unlock_irqrestore(&counter->lock, flags);
+ return 0;
}
Index: container-2.6.23-rc8-mm2/mm/memcontrol.c
===================================================================
--- container-2.6.23-rc8-mm2.orig/mm/memcontrol.c
+++ container-2.6.23-rc8-mm2/mm/memcontrol.c
@@ -432,112 +432,59 @@ void mem_cgroup_uncharge(struct page_cgr
}
}
-int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
-{
- *tmp = memparse(buf, &buf);
- if (*buf != '\0')
- return -EINVAL;
-
- /*
- * Round up the value to the closest page size
- */
- *tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT;
- return 0;
-}
-
-static ssize_t mem_cgroup_read(struct cgroup *cont,
- struct cftype *cft, struct file *file,
- char __user *userbuf, size_t nbytes, loff_t *ppos)
+static unsigned long long mem_cgroup_read(struct cgroup *cont,
+ struct cftype *cft)
{
return res_counter_read(&mem_cgroup_from_cont(cont)->res,
- cft->private, userbuf, nbytes, ppos,
- NULL);
+ cft->private);
}
-static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
- struct file *file, const char __user *userbuf,
- size_t nbytes, loff_t *ppos)
+static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
+ unsigned long long val)
{
+ /* Don't allow the limit to be set for the root cgroup */
+ if (!cont->parent)
+ return -EINVAL;
return res_counter_write(&mem_cgroup_from_cont(cont)->res,
- cft->private, userbuf, nbytes, ppos,
- mem_cgroup_write_strategy);
+ cft->private, PAGE_ALIGN(val));
}
-static ssize_t mem_control_type_write(struct cgroup *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_cgroup *mem;
-
- mem = mem_cgroup_from_cont(cont);
- buf = kmalloc(nbytes + 1, GFP_KERNEL);
- ret = -ENOMEM;
- if (buf == NULL)
- goto out;
-
- 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_CGROUP_TYPE_UNSPEC || tmp >= MEM_CGROUP_TYPE_MAX)
- goto out_free;
-
- mem->control_type = tmp;
- ret = nbytes;
-out_free:
- kfree(buf);
-out:
- return ret;
+static int mem_control_type_write(struct cgroup *cont, struct cftype *cft,
+ u64 val)
+{
+ if (val <= MEM_CGROUP_TYPE_UNSPEC || val >= MEM_CGROUP_TYPE_MAX)
+ return -EINVAL;
+ mem_cgroup_from_cont(cont)->control_type = val;
+ return 0;
}
-static ssize_t mem_control_type_read(struct cgroup *cont,
- struct cftype *cft,
- struct file *file, char __user *userbuf,
- size_t nbytes, loff_t *ppos)
+static u64 mem_control_type_read(struct cgroup *cont,
+ struct cftype *cft)
{
- unsigned long val;
- char buf[64], *s;
- struct mem_cgroup *mem;
-
- mem = mem_cgroup_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);
+ return mem_cgroup_from_cont(cont)->control_type;
}
static struct cftype mem_cgroup_files[] = {
{
.name = "usage_in_bytes",
.private = RES_USAGE,
- .read = mem_cgroup_read,
+ .read_uint = mem_cgroup_read,
},
{
.name = "limit_in_bytes",
.private = RES_LIMIT,
- .write = mem_cgroup_write,
- .read = mem_cgroup_read,
+ .write_uint = mem_cgroup_write,
+ .read_uint = mem_cgroup_read,
},
{
.name = "failcnt",
.private = RES_FAILCNT,
- .read = mem_cgroup_read,
+ .read_uint = mem_cgroup_read,
},
{
.name = "control_type",
- .write = mem_control_type_write,
- .read = mem_control_type_read,
+ .write_uint = mem_control_type_write,
+ .read_uint = mem_control_type_read,
},
};
Index: container-2.6.23-rc8-mm2/include/linux/cgroup.h
===================================================================
--- container-2.6.23-rc8-mm2.orig/include/linux/cgroup.h
+++ container-2.6.23-rc8-mm2/include/linux/cgroup.h
@@ -199,7 +199,7 @@ struct cftype {
/*
* write_uint() is a shortcut for the common case of accepting
- * a single integer (as parsed by simple_strtoull) from
+ * a single integer (as parsed by lib/cmdline.c:memparse()) from
* userspace. Use in place of write(); return 0 or error.
*/
int (*write_uint) (struct cgroup *cont, struct cftype *cft, u64 val);
Index: container-2.6.23-rc8-mm2/kernel/cgroup.c
===================================================================
--- container-2.6.23-rc8-mm2.orig/kernel/cgroup.c
+++ container-2.6.23-rc8-mm2/kernel/cgroup.c
@@ -1296,7 +1296,7 @@ static ssize_t cgroup_write_uint(struct
/* strip newline if necessary */
if (nbytes && (buffer[nbytes-1] == '\n'))
buffer[nbytes-1] = 0;
- val = simple_strtoull(buffer, &end, 0);
+ val = memparse(buffer, &end);
if (*end)
return -EINVAL;
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