[Cluster-devel] [PATCH][GFS2] Bouncing locks in a cluster is slow in GFS2 - Try #2
Bob Peterson
rpeterso at redhat.com
Thu Jan 27 02:25:44 UTC 2011
----- Original Message -----
| Hi,
|
| You shouldn't need to do the dual workqueue trick upstream since the
| workqueues will already start as many threads as required (so even
| better than just using the two here). If that isn't happening we
| should
| ask Tejun about it.
|
| So I think we only need the min hold time bit here,
|
| Steve.
Hi,
Based on your feedback, I reworked this patch a bit. This is take two.
Rather than using a "qwork" function to police the delay based on
glock type, I went back to the original queue_delayed_work and
adjusted delay based on glock type. So this version has fewer lines
changed, but still accomplishes the same thing.
Note that I had to tweak function glock_work_func in order to
preserve the rather odd logic that decides whether or not to
actually queue the work.
This patch is a performance improvement for GFS2 in a clustered
environment. It makes the glock hold time self-adjusting.
Regards,
Bob Peterson
Red Hat File Systems
Signed-off-by: Bob Peterson <rpeterso at redhat.com>
Bouncing locks in a cluster is slow in GFS2
--
[Cluster-devel] [PATCH][GFS2] Bouncing locks in a cluster is slow in GFS2
fs/gfs2/glock.c | 39 +++++++++++++++++++++++++++++----------
fs/gfs2/glock.h | 6 ++++++
fs/gfs2/glops.c | 2 --
fs/gfs2/incore.h | 2 +-
4 files changed, 36 insertions(+), 13 deletions(-)
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index c75d499..0523b20 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -407,6 +407,10 @@ static void state_change(struct gfs2_glock *gl, unsigned int new_state)
if (held1 && held2 && list_empty(&gl->gl_holders))
clear_bit(GLF_QUEUED, &gl->gl_flags);
+ if (new_state != gl->gl_target)
+ /* shorten our minimum hold time */
+ gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
+ GL_GLOCK_MIN_HOLD);
gl->gl_state = new_state;
gl->gl_tchange = jiffies;
}
@@ -670,16 +674,21 @@ static void glock_work_func(struct work_struct *work)
gl->gl_state != LM_ST_UNLOCKED &&
gl->gl_demote_state != LM_ST_EXCLUSIVE) {
unsigned long holdtime, now = jiffies;
- holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
+ holdtime = gl->gl_tchange + gl->gl_hold_time;
if (time_before(now, holdtime))
delay = holdtime - now;
set_bit(delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE, &gl->gl_flags);
}
run_queue(gl, 0);
spin_unlock(&gl->gl_spin);
- if (!delay ||
- queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
+ if (!delay)
gfs2_glock_put(gl);
+ else {
+ if (gl->gl_name.ln_type != LM_TYPE_INODE)
+ delay = 0;
+ if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
+ gfs2_glock_put(gl);
+ }
if (drop_ref)
gfs2_glock_put(gl);
}
@@ -741,6 +750,7 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
gl->gl_tchange = jiffies;
gl->gl_object = NULL;
gl->gl_sbd = sdp;
+ gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
INIT_WORK(&gl->gl_delete, delete_work_func);
@@ -852,8 +862,15 @@ static int gfs2_glock_demote_wait(void *word)
static void wait_on_holder(struct gfs2_holder *gh)
{
+ unsigned long time1 = jiffies;
+
might_sleep();
wait_on_bit(&gh->gh_iflags, HIF_WAIT, gfs2_glock_holder_wait, TASK_UNINTERRUPTIBLE);
+ if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
+ /* Lengthen the minimum hold time. */
+ gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
+ GL_GLOCK_HOLD_INCR,
+ GL_GLOCK_MAX_HOLD);
}
static void wait_on_demote(struct gfs2_glock *gl)
@@ -1086,8 +1103,9 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
gfs2_glock_hold(gl);
if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
- !test_bit(GLF_DEMOTE, &gl->gl_flags))
- delay = gl->gl_ops->go_min_hold_time;
+ !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
+ gl->gl_name.ln_type == LM_TYPE_INODE)
+ delay = gl->gl_hold_time;
if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
gfs2_glock_put(gl);
}
@@ -1270,12 +1288,13 @@ void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
unsigned long now = jiffies;
gfs2_glock_hold(gl);
- holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
- if (test_bit(GLF_QUEUED, &gl->gl_flags)) {
+ holdtime = gl->gl_tchange + gl->gl_hold_time;
+ if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
+ gl->gl_name.ln_type == LM_TYPE_INODE) {
if (time_before(now, holdtime))
delay = holdtime - now;
if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
- delay = gl->gl_ops->go_min_hold_time;
+ delay = gl->gl_hold_time;
}
spin_lock(&gl->gl_spin);
@@ -1658,7 +1677,7 @@ static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
dtime *= 1000000/HZ; /* demote time in uSec */
if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
dtime = 0;
- gfs2_print_dbg(seq, "G: s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d r:%d\n",
+ gfs2_print_dbg(seq, "G: s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d r:%d m:%ld\n",
state2str(gl->gl_state),
gl->gl_name.ln_type,
(unsigned long long)gl->gl_name.ln_number,
@@ -1666,7 +1685,7 @@ static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
state2str(gl->gl_target),
state2str(gl->gl_demote_state), dtime,
atomic_read(&gl->gl_ail_count),
- atomic_read(&gl->gl_ref));
+ atomic_read(&gl->gl_ref), gl->gl_hold_time);
list_for_each_entry(gh, &gl->gl_holders, gh_list) {
error = dump_holder(seq, gh);
diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
index afa8bfe..3233add 100644
--- a/fs/gfs2/glock.h
+++ b/fs/gfs2/glock.h
@@ -113,6 +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_MIN_HOLD (long)(0)
+#define GL_GLOCK_HOLD_INCR (long)(HZ / 20)
+#define GL_GLOCK_HOLD_DECR (long)(HZ / 40)
+
struct lm_lockops {
const char *lm_proto_name;
int (*lm_mount) (struct gfs2_sbd *sdp, const char *fsname);
diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index ac5fac9..bba125e 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -399,7 +399,6 @@ const struct gfs2_glock_operations gfs2_inode_glops = {
.go_lock = inode_go_lock,
.go_dump = inode_go_dump,
.go_type = LM_TYPE_INODE,
- .go_min_hold_time = HZ / 5,
.go_flags = GLOF_ASPACE,
};
@@ -410,7 +409,6 @@ const struct gfs2_glock_operations gfs2_rgrp_glops = {
.go_unlock = rgrp_go_unlock,
.go_dump = gfs2_rgrp_dump,
.go_type = LM_TYPE_RGRP,
- .go_min_hold_time = HZ / 5,
.go_flags = GLOF_ASPACE,
};
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 720c1e6..f21f075 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -163,7 +163,6 @@ struct gfs2_glock_operations {
int (*go_dump)(struct seq_file *seq, const struct gfs2_glock *gl);
void (*go_callback) (struct gfs2_glock *gl);
const int go_type;
- const unsigned long go_min_hold_time;
const unsigned long go_flags;
#define GLOF_ASPACE 1
};
@@ -237,6 +236,7 @@ struct gfs2_glock {
struct delayed_work gl_work;
struct work_struct gl_delete;
struct rcu_head gl_rcu;
+ long gl_hold_time;
};
#define GFS2_MIN_LVB_SIZE 32 /* Min size of LVB that gfs2 supports */
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