[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>
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 32b48e8..817ba25 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -742,18 +742,18 @@
{
.ctl_name = VM_DIRTY_WB_CS,
.procname = "dirty_writeback_centisecs",
- .data = &dirty_writeback_centisecs,
- .maxlen = sizeof(dirty_writeback_centisecs),
+ .data = &dirty_writeback_interval,
+ .maxlen = sizeof(dirty_writeback_interval),
.mode = 0644,
.proc_handler = &dirty_writeback_centisecs_handler,
},
{
.ctl_name = VM_DIRTY_EXPIRE_CS,
.procname = "dirty_expire_centisecs",
- .data = &dirty_expire_centisecs,
- .maxlen = sizeof(dirty_expire_centisecs),
+ .data = &dirty_expire_interval,
+ .maxlen = sizeof(dirty_expire_interval),
.mode = 0644,
- .proc_handler = &proc_dointvec,
+ .proc_handler = &proc_dointvec_userhz_jiffies,
},
{
.ctl_name = VM_NR_PDFLUSH_THREADS,