Properly notify block layer of sync writes

[linux-2.6] / include / linux / res_counter.h

diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index eeb3f7749772d3b0b3166893d275ee7ef78b40bb..6d9e1fca098c468b49287791e181f6e4f51e7d54 100644 (file)
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -9,6 +9,8 @@
  *
  * Author: Pavel Emelianov <xemul@openvz.org>
  *
+ * See Documentation/controllers/resource_counter.txt for more
+ * info about what this counter is.
  */
 
 #include <linux/cgroup.h>
@@ -23,15 +25,19 @@ struct res_counter {
        /*
         * the current resource consumption level
         */
-       unsigned long usage;
+       unsigned long long usage;
+       /*
+        * the maximal value of the usage from the counter creation
+        */
+       unsigned long long max_usage;
        /*
         * the limit that usage cannot exceed
         */
-       unsigned long limit;
+       unsigned long long limit;
        /*
         * the number of unsuccessful attempts to consume the resource
         */
-       unsigned long failcnt;
+       unsigned long long failcnt;
        /*
         * the lock to protect all of the above.
         * the routines below consider this to be IRQ-safe
@@ -39,8 +45,9 @@ struct res_counter {
        spinlock_t lock;
 };
 
-/*
+/**
  * Helpers to interact with userspace
+ * res_counter_read_u64() - returns the value of the specified member.
  * res_counter_read/_write - put/get the specified fields from the
  * res_counter struct to/from the user
  *
@@ -51,10 +58,14 @@ struct res_counter {
  * @pos:     and the offset.
  */
 
+u64 res_counter_read_u64(struct res_counter *counter, int member);
+
 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
@@ -62,6 +73,7 @@ ssize_t res_counter_write(struct res_counter *counter, int member,
 
 enum {
        RES_USAGE,
+       RES_MAX_USAGE,
        RES_LIMIT,
        RES_FAILCNT,
 };
@@ -99,4 +111,44 @@ int res_counter_charge(struct res_counter *counter, unsigned long val);
 void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
 void res_counter_uncharge(struct res_counter *counter, unsigned long val);
 
+static inline bool res_counter_limit_check_locked(struct res_counter *cnt)
+{
+       if (cnt->usage < cnt->limit)
+               return true;
+
+       return false;
+}
+
+/*
+ * Helper function to detect if the cgroup is within it's limit or
+ * not. It's currently called from cgroup_rss_prepare()
+ */
+static inline bool res_counter_check_under_limit(struct res_counter *cnt)
+{
+       bool ret;
+       unsigned long flags;
+
+       spin_lock_irqsave(&cnt->lock, flags);
+       ret = res_counter_limit_check_locked(cnt);
+       spin_unlock_irqrestore(&cnt->lock, flags);
+       return ret;
+}
+
+static inline void res_counter_reset_max(struct res_counter *cnt)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&cnt->lock, flags);
+       cnt->max_usage = cnt->usage;
+       spin_unlock_irqrestore(&cnt->lock, flags);
+}
+
+static inline void res_counter_reset_failcnt(struct res_counter *cnt)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&cnt->lock, flags);
+       cnt->failcnt = 0;
+       spin_unlock_irqrestore(&cnt->lock, flags);
+}
 #endif