fs: add dirtytime_expire_seconds sysctl
Add a tuning knob so we can adjust the dirtytime expiration timeout,
which is very useful for testing lazytime.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 2cfcd74..32a8bbd 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1188,6 +1188,17 @@
}
__initcall(start_dirtytime_writeback);
+int dirtytime_interval_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ int ret;
+
+ ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+ if (ret == 0 && write)
+ mod_delayed_work(system_wq, &dirtytime_work, 0);
+ return ret;
+}
+
static noinline void block_dump___mark_inode_dirty(struct inode *inode)
{
if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) {
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 0004833..b2dd371e 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -130,6 +130,7 @@
extern unsigned long vm_dirty_bytes;
extern unsigned int dirty_writeback_interval;
extern unsigned int dirty_expire_interval;
+extern unsigned int dirtytime_expire_interval;
extern int vm_highmem_is_dirtyable;
extern int block_dump;
extern int laptop_mode;
@@ -146,6 +147,8 @@
extern int dirty_bytes_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos);
+int dirtytime_interval_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos);
struct ctl_table;
int dirty_writeback_centisecs_handler(struct ctl_table *, int,
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 88ea2d6..ce410bb 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1228,6 +1228,14 @@
.extra1 = &zero,
},
{
+ .procname = "dirtytime_expire_seconds",
+ .data = &dirtytime_expire_interval,
+ .maxlen = sizeof(dirty_expire_interval),
+ .mode = 0644,
+ .proc_handler = dirtytime_interval_handler,
+ .extra1 = &zero,
+ },
+ {
.procname = "nr_pdflush_threads",
.mode = 0444 /* read-only */,
.proc_handler = pdflush_proc_obsolete,