Memory controller improve user interface

Change the interface to use bytes 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.

[kamezawa.hiroyu@jp.fujitsu.com: possible race fix in res_counter]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
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: David Rientjes <rientjes@google.com>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 5 deletions

diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index 5e60a4f34243..61363ce896d5 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -23,15 +23,15 @@ 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
          */
-        unsigned long failcnt;
+        unsigned long long failcnt;
         /*
          * the lock to protect all of the above.
          * the routines below consider this to be IRQ-safe
@@ -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