[Cluster-devel] [GFS2 PATCH] GFS2: Adjust minimum hold times

[Bob Peterson <rpeterso@redhat.com>]

Hi,

This patch adjusts the glock minimum hold times to smaller values.
It also increases the hold time for each new holder record queued.

Regards,

Bob Peterson
Red Hat File Systems

Signed-off-by: Bob Peterson <rpeterso@redhat.com> 
---
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index e543871..beaa834 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -985,6 +985,9 @@ fail:
 	trace_gfs2_glock_queue(gh, 1);
 	gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
 	gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
+	/* For every new holder, add to the minimum hold time, up to the max */
+	gl->gl_hold_time = min(gl->gl_hold_time + GL_GLOCK_PERHOLDER_INCR,
+			       GL_GLOCK_MAX_HOLD);
 	if (likely(insert_pt == NULL)) {
 		list_add_tail(&gh->gh_list, &gl->gl_holders);
 		if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
@@ -1079,6 +1082,9 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
 	if (gh->gh_flags & GL_NOCACHE)
 		handle_callback(gl, LM_ST_UNLOCKED, 0);
 
+	/* One less holder, so adjust the minimum hold time down. */
+	gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_PERHOLDER_INCR,
+			       GL_GLOCK_MIN_HOLD);
 	list_del_init(&gh->gh_list);
 	if (find_first_holder(gl) == NULL) {
 		if (glops->go_unlock) {
diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
index fd580b7..52068de 100644
--- a/fs/gfs2/glock.h
+++ b/fs/gfs2/glock.h
@@ -113,11 +113,12 @@ enum {
 
 #define GLR_TRYFAILED		13
 
-#define GL_GLOCK_MAX_HOLD        (long)(HZ / 5)
-#define GL_GLOCK_DFT_HOLD        (long)(HZ / 5)
+#define GL_GLOCK_MAX_HOLD        (long)(HZ / 10)
+#define GL_GLOCK_DFT_HOLD        (long)(HZ / 10)
 #define GL_GLOCK_MIN_HOLD        (long)(10)
 #define GL_GLOCK_HOLD_INCR       (long)(HZ / 20)
 #define GL_GLOCK_HOLD_DECR       (long)(HZ / 40)
+#define GL_GLOCK_PERHOLDER_INCR  (long)(2)
 
 struct lm_lockops {
 	const char *lm_proto_name;