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>

1 files changed, 8 insertions, 0 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 88ea2d6e0031..ce410bb9f2e1 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1228,6 +1228,14 @@ static struct ctl_table vm_table[] = {
                 .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,