[PATCH] Represent dirty_*_centisecs as jiffies internally

Make that the internal values for:

/proc/sys/vm/dirty_writeback_centisecs
/proc/sys/vm/dirty_expire_centisecs

are stored as jiffies instead of centiseconds.  Let the sysctl interface do
the conversions with full precision using clock_t_to_jiffies, instead of
doing overflow-sensitive on-the-fly conversions every time the values are
used.

Cons: apparent precision loss if HZ is not a multiple of 100, because of
conversion back and forth.  This is a common problem for all sysctl values
that use proc_dointvec_userhz_jiffies.  (There is only one other in-tree
use, in net/core/neighbour.c.)

Signed-off-by: Bart Samwel <bart@samwel.tk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index beaef5c7a0ea..609565961494 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -88,8 +88,8 @@ void throttle_vm_writeout(void);
 /* These are exported to sysctl. */
 extern int dirty_background_ratio;
 extern int vm_dirty_ratio;
-extern int dirty_writeback_centisecs;
-extern int dirty_expire_centisecs;
+extern int dirty_writeback_interval;
+extern int dirty_expire_interval;
 extern int block_dump;
 extern int laptop_mode;