[GFS2] Remove remote lock dropping code

There are several reasons why this is undesirable:

 1. It never happens during normal operation anyway
 2. If it does happen it causes performance to be very, very poor
 3. It isn't likely to solve the original problem (memory shortage
    on remote DLM node) it was supposed to solve
 4. It uses a bunch of arbitrary constants which are unlikely to be
    correct for any particular situation and for which the tuning seems
    to be a black art.
 5. In an N node cluster, only 1/N of the dropped locked will actually
    contribute to solving the problem on average.

So all in all we are better off without it. This also makes merging
the lock_dlm module into GFS2 a bit easier.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

4 files changed, 0 insertions, 38 deletions

diff --git a/fs/gfs2/locking/dlm/lock_dlm.h b/fs/gfs2/locking/dlm/lock_dlm.h
index ad944c6..845a27f 100644
--- a/fs/gfs2/locking/dlm/lock_dlm.h
+++ b/fs/gfs2/locking/dlm/lock_dlm.h
@@ -79,9 +79,6 @@ struct gdlm_ls {
 	wait_queue_head_t	wait_control;
 	struct task_struct	*thread;
 	wait_queue_head_t	thread_wait;
-	unsigned long		drop_time;
-	int			drop_locks_count;
-	int			drop_locks_period;
 };
 
 enum {
diff --git a/fs/gfs2/locking/dlm/mount.c b/fs/gfs2/locking/dlm/mount.c
index 0628520..fa31c54 100644
--- a/fs/gfs2/locking/dlm/mount.c
+++ b/fs/gfs2/locking/dlm/mount.c
@@ -22,8 +22,6 @@ static struct gdlm_ls *init_gdlm(lm_callback_t cb, struct gfs2_sbd *sdp,
 	if (!ls)
 		return NULL;
 
-	ls->drop_locks_count = GDLM_DROP_COUNT;
-	ls->drop_locks_period = GDLM_DROP_PERIOD;
 	ls->fscb = cb;
 	ls->sdp = sdp;
 	ls->fsflags = flags;
@@ -33,7 +31,6 @@ static struct gdlm_ls *init_gdlm(lm_callback_t cb, struct gfs2_sbd *sdp,
 	INIT_LIST_HEAD(&ls->all_locks);
 	init_waitqueue_head(&ls->thread_wait);
 	init_waitqueue_head(&ls->wait_control);
-	ls->drop_time = jiffies;
 	ls->jid = -1;
 
 	strncpy(buf, table_name, 256);
diff --git a/fs/gfs2/locking/dlm/sysfs.c b/fs/gfs2/locking/dlm/sysfs.c
index a4ff271..4ec571c 100644
--- a/fs/gfs2/locking/dlm/sysfs.c
+++ b/fs/gfs2/locking/dlm/sysfs.c
@@ -114,17 +114,6 @@ static ssize_t recover_status_show(struct gdlm_ls *ls, char *buf)
 	return sprintf(buf, "%d\n", ls->recover_jid_status);
 }
 
-static ssize_t drop_count_show(struct gdlm_ls *ls, char *buf)
-{
-	return sprintf(buf, "%d\n", ls->drop_locks_count);
-}
-
-static ssize_t drop_count_store(struct gdlm_ls *ls, const char *buf, size_t len)
-{
-	ls->drop_locks_count = simple_strtol(buf, NULL, 0);
-	return len;
-}
-
 struct gdlm_attr {
 	struct attribute attr;
 	ssize_t (*show)(struct gdlm_ls *, char *);
@@ -144,7 +133,6 @@ GDLM_ATTR(first_done,     0444, first_done_show,     NULL);
 GDLM_ATTR(recover,        0644, recover_show,        recover_store);
 GDLM_ATTR(recover_done,   0444, recover_done_show,   NULL);
 GDLM_ATTR(recover_status, 0444, recover_status_show, NULL);
-GDLM_ATTR(drop_count,     0644, drop_count_show,     drop_count_store);
 
 static struct attribute *gdlm_attrs[] = {
 	&gdlm_attr_proto_name.attr,
@@ -157,7 +145,6 @@ static struct attribute *gdlm_attrs[] = {
 	&gdlm_attr_recover.attr,
 	&gdlm_attr_recover_done.attr,
 	&gdlm_attr_recover_status.attr,
-	&gdlm_attr_drop_count.attr,
 	NULL,
 };
 
diff --git a/fs/gfs2/locking/dlm/thread.c b/fs/gfs2/locking/dlm/thread.c
index f30350a..38823ef 100644
--- a/fs/gfs2/locking/dlm/thread.c
+++ b/fs/gfs2/locking/dlm/thread.c
@@ -20,19 +20,6 @@ static inline int no_work(struct gdlm_ls *ls)
 	return ret;
 }
 
-static inline int check_drop(struct gdlm_ls *ls)
-{
-	if (!ls->drop_locks_count)
-		return 0;
-
-	if (time_after(jiffies, ls->drop_time + ls->drop_locks_period * HZ)) {
-		ls->drop_time = jiffies;
-		if (ls->all_locks_count >= ls->drop_locks_count)
-			return 1;
-	}
-	return 0;
-}
-
 static int gdlm_thread(void *data)
 {
 	struct gdlm_ls *ls = (struct gdlm_ls *) data;
@@ -52,12 +39,6 @@ static int gdlm_thread(void *data)
 			gdlm_do_lock(lp);
 			spin_lock(&ls->async_lock);
 		}
-		/* Does this ever happen these days? I hope not anyway */
-		if (check_drop(ls)) {
-			spin_unlock(&ls->async_lock);
-			ls->fscb(ls->sdp, LM_CB_DROPLOCKS, NULL);
-			spin_lock(&ls->async_lock);
-		}
 		spin_unlock(&ls->async_lock);
 	}