Memory controller: resource counters

With fixes from David Rientjes <rientjes@google.com>

Introduce generic structures and routines for resource accounting.

Each resource accounting cgroup is supposed to aggregate it,
cgroup_subsystem_state and its resource-specific members within.

Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 120 insertions, 0 deletions

diff --git a/kernel/res_counter.c b/kernel/res_counter.c
new file mode 100644
index 000000000000..722c484b068b
--- /dev/null
+++ b/kernel/res_counter.c
@@ -0,0 +1,120 @@
+/*
+ * resource cgroups
+ *
+ * Copyright 2007 OpenVZ SWsoft Inc
+ *
+ * Author: Pavel Emelianov <xemul@openvz.org>
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/parser.h>
+#include <linux/fs.h>
+#include <linux/res_counter.h>
+#include <linux/uaccess.h>
+
+void res_counter_init(struct res_counter *counter)
+{
+        spin_lock_init(&counter->lock);
+        counter->limit = (unsigned long)LONG_MAX;
+}
+
+int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
+{
+        if (counter->usage + val > counter->limit) {
+                counter->failcnt++;
+                return -ENOMEM;
+        }
+
+        counter->usage += val;
+        return 0;
+}
+
+int res_counter_charge(struct res_counter *counter, unsigned long val)
+{
+        int ret;
+        unsigned long flags;
+
+        spin_lock_irqsave(&counter->lock, flags);
+        ret = res_counter_charge_locked(counter, val);
+        spin_unlock_irqrestore(&counter->lock, flags);
+        return ret;
+}
+
+void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
+{
+        if (WARN_ON(counter->usage < val))
+                val = counter->usage;
+
+        counter->usage -= val;
+}
+
+void res_counter_uncharge(struct res_counter *counter, unsigned long val)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&counter->lock, flags);
+        res_counter_uncharge_locked(counter, val);
+        spin_unlock_irqrestore(&counter->lock, flags);
+}
+
+
+static inline unsigned long *res_counter_member(struct res_counter *counter,
+                                                int member)
+{
+        switch (member) {
+        case RES_USAGE:
+                return &counter->usage;
+        case RES_LIMIT:
+                return &counter->limit;
+        case RES_FAILCNT:
+                return &counter->failcnt;
+        };
+
+        BUG();
+        return NULL;
+}
+
+ssize_t res_counter_read(struct res_counter *counter, int member,
+                const char __user *userbuf, size_t nbytes, loff_t *pos)
+{
+        unsigned long *val;
+        char buf[64], *s;
+
+        s = buf;
+        val = res_counter_member(counter, member);
+        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)
+{
+        int ret;
+        char *buf, *end;
+        unsigned 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;
+        tmp = simple_strtoul(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;
+}