core: make the per glusterfs_ctx_t timer-wheel refcounted

xlators can use a 'global' timer-wheel for scheduling events. This
timer-wheel is managed per glusterfs_ctx_t, but does not need to be
allocated for every graph. When an xlator wants to use the timer-wheel,
it will be instanciated on demand, and provided to xlators that request
it later on.

By adding a reference counter to the glusterfs_ctx_t for the
timer-wheel, the threads and structures can be cleaned up when the last
xlator does not have a need for it anymore. In general, the xlators
request the timer-wheel in init(), and they should return it in fini().

Because the timer-wheel is managed per glusterfs_ctx_t, the functions
can be added to ctx.c and do not need to live in their very minimal
tw.[ch] files.

Change-Id: I19d225b39aaa272d9005ba7adc3104c3764f1572
BUG: 1442788
Reported-by: Poornima G <pgurusid@redhat.com>
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: https://review.gluster.org/17068
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Smoke: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Reviewed-by: Zhou Zhengping <johnzzpcrystal@gmail.com>
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>

1 files changed, 6 insertions, 12 deletions

diff --git a/xlators/features/leases/src/leases.c b/xlators/features/leases/src/leases.c
index 3e0460000d7..faffa0e71f8 100644
--- a/xlators/features/leases/src/leases.c
+++ b/xlators/features/leases/src/leases.c
@@ -957,19 +957,11 @@ leases_init_priv (xlator_t *this)
         GF_ASSERT (priv);
 
         if (!priv->timer_wheel) {
-                if (!glusterfs_global_timer_wheel (this)) {
-                        gf_msg_debug (this->name, 0, "Initing the global "
-                                      "timer wheel");
-                        ret = glusterfs_global_timer_wheel_init (this->ctx);
-                        if (ret) {
-                                gf_msg (this->name, GF_LOG_ERROR, 0,
-                                        LEASE_MSG_NO_TIMER_WHEEL,
-                                        "Initing the global timer "
-                                        "wheel failed");
-                                goto out;
-                        }
+                priv->timer_wheel = glusterfs_ctx_tw_get (this->ctx);
+                if (!priv->timer_wheel) {
+                        ret = -1;
+                        goto out;
                 }
-                priv->timer_wheel = glusterfs_global_timer_wheel (this);
         }
 
         if (!priv->inited_recall_thr) {
@@ -1076,6 +1068,8 @@ fini (xlator_t *this)
 
         GF_FREE (priv);
 
+        glusterfs_ctx_tw_put (this->ctx);
+
         return 0;
 }