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authorBenjamin Marzinski <bmarzins@redhat.com>2009-07-10 18:04:24 -0500
committerSteven Whitehouse <swhiteho@redhat.com>2009-07-30 11:00:09 +0100
commit8ff22a6f9bdaac87c0eeb1d56c736181f11b4221 (patch)
tree00b0ad7afe45497d251adb244baf6875a0744985
parent1e19a19584b332eb92a573b66b7342fb97e67507 (diff)
GFS2: Don't put unlikely reclaim candidates on the reclaim list.
GFS2 was placing far too many glocks on the reclaim list that were not good candidates for freeing up from cache. These locks would sit there and repeatedly get scanned to see if they could be reclaimed, wasting a lot of time when there was memory pressure. This fix does more checks on the locks to see if they are actually likely to be removable from cache. Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
-rw-r--r--fs/gfs2/glock.c72
1 files changed, 46 insertions, 26 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 827136ee794c..f041a89e1ab8 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -174,6 +174,26 @@ static void gfs2_glock_hold(struct gfs2_glock *gl)
}
/**
+ * demote_ok - Check to see if it's ok to unlock a glock
+ * @gl: the glock
+ *
+ * Returns: 1 if it's ok
+ */
+
+static int demote_ok(const struct gfs2_glock *gl)
+{
+ const struct gfs2_glock_operations *glops = gl->gl_ops;
+
+ if (gl->gl_state == LM_ST_UNLOCKED)
+ return 0;
+ if (!list_empty(&gl->gl_holders))
+ return 0;
+ if (glops->go_demote_ok)
+ return glops->go_demote_ok(gl);
+ return 1;
+}
+
+/**
* gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
* @gl: the glock
*
@@ -181,8 +201,13 @@ static void gfs2_glock_hold(struct gfs2_glock *gl)
static void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
{
+ int may_reclaim;
+ may_reclaim = (demote_ok(gl) &&
+ (atomic_read(&gl->gl_ref) == 1 ||
+ (gl->gl_name.ln_type == LM_TYPE_INODE &&
+ atomic_read(&gl->gl_ref) <= 2)));
spin_lock(&lru_lock);
- if (list_empty(&gl->gl_lru) && gl->gl_state != LM_ST_UNLOCKED) {
+ if (list_empty(&gl->gl_lru) && may_reclaim) {
list_add_tail(&gl->gl_lru, &lru_list);
atomic_inc(&lru_count);
}
@@ -190,6 +215,21 @@ static void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
}
/**
+ * gfs2_glock_put_nolock() - Decrement reference count on glock
+ * @gl: The glock to put
+ *
+ * This function should only be used if the caller has its own reference
+ * to the glock, in addition to the one it is dropping.
+ */
+
+static void gfs2_glock_put_nolock(struct gfs2_glock *gl)
+{
+ if (atomic_dec_and_test(&gl->gl_ref))
+ GLOCK_BUG_ON(gl, 1);
+ gfs2_glock_schedule_for_reclaim(gl);
+}
+
+/**
* gfs2_glock_put() - Decrement reference count on glock
* @gl: The glock to put
*
@@ -214,9 +254,9 @@ int gfs2_glock_put(struct gfs2_glock *gl)
rv = 1;
goto out;
}
- /* 1 for being hashed, 1 for having state != LM_ST_UNLOCKED */
- if (atomic_read(&gl->gl_ref) == 2)
- gfs2_glock_schedule_for_reclaim(gl);
+ spin_lock(&gl->gl_spin);
+ gfs2_glock_schedule_for_reclaim(gl);
+ spin_unlock(&gl->gl_spin);
write_unlock(gl_lock_addr(gl->gl_hash));
out:
return rv;
@@ -398,7 +438,7 @@ static void state_change(struct gfs2_glock *gl, unsigned int new_state)
if (held2)
gfs2_glock_hold(gl);
else
- gfs2_glock_put(gl);
+ gfs2_glock_put_nolock(gl);
}
gl->gl_state = new_state;
@@ -633,7 +673,7 @@ out:
out_sched:
gfs2_glock_hold(gl);
if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
- gfs2_glock_put(gl);
+ gfs2_glock_put_nolock(gl);
out_unlock:
clear_bit(GLF_LOCK, &gl->gl_flags);
goto out;
@@ -1274,26 +1314,6 @@ void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
gfs2_glock_put(gl);
}
-/**
- * demote_ok - Check to see if it's ok to unlock a glock
- * @gl: the glock
- *
- * Returns: 1 if it's ok
- */
-
-static int demote_ok(const struct gfs2_glock *gl)
-{
- const struct gfs2_glock_operations *glops = gl->gl_ops;
-
- if (gl->gl_state == LM_ST_UNLOCKED)
- return 0;
- if (!list_empty(&gl->gl_holders))
- return 0;
- if (glops->go_demote_ok)
- return glops->go_demote_ok(gl);
- return 1;
-}
-
static int gfs2_shrink_glock_memory(int nr, gfp_t gfp_mask)
{