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>

4 files changed, 16 insertions, 27 deletions

diff --git a/xlators/features/bit-rot/src/bitd/bit-rot.c b/xlators/features/bit-rot/src/bitd/bit-rot.c
index e55a22f1cdc..6e86ceb02e7 100644
--- a/xlators/features/bit-rot/src/bitd/bit-rot.c
+++ b/xlators/features/bit-rot/src/bitd/bit-rot.c
@@ -21,8 +21,6 @@
 #include <pthread.h>
 #include "bit-rot-bitd-messages.h"
 
-#include "tw.h"
-
 #define BR_HASH_CALC_READ_SIZE  (128 * 1024)
 
 typedef int32_t (br_child_handler)(xlator_t *, br_child_t *);
@@ -1994,7 +1992,7 @@ init (xlator_t *this)
         INIT_LIST_HEAD (&priv->bricks);
         INIT_LIST_HEAD (&priv->signing);
 
-        priv->timer_wheel = glusterfs_global_timer_wheel (this);
+        priv->timer_wheel = glusterfs_ctx_tw_get (this->ctx);
         if (!priv->timer_wheel) {
                 gf_msg (this->name, GF_LOG_ERROR, 0,
                         BRB_MSG_TIMER_WHEEL_UNAVAILABLE,
@@ -2062,6 +2060,8 @@ fini (xlator_t *this)
         this->private = NULL;
 	GF_FREE (priv);
 
+        glusterfs_ctx_tw_put (this->ctx);
+
 	return;
 }
 
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;
 }
 
diff --git a/xlators/features/leases/src/leases.h b/xlators/features/leases/src/leases.h
index 703c4d809cd..443c6a22324 100644
--- a/xlators/features/leases/src/leases.h
+++ b/xlators/features/leases/src/leases.h
@@ -26,7 +26,6 @@
 #include "lkowner.h"
 #include "locking.h"
 #include "upcall-utils.h"
-#include "tw.h"
 #include "timer-wheel.h"
 #include "leases-mem-types.h"
 #include "leases-messages.h"
diff --git a/xlators/performance/nl-cache/src/nl-cache.c b/xlators/performance/nl-cache/src/nl-cache.c
index f301b2d06dd..f8d2642be30 100644
--- a/xlators/performance/nl-cache/src/nl-cache.c
+++ b/xlators/performance/nl-cache/src/nl-cache.c
@@ -12,7 +12,6 @@
 #include "nl-cache.h"
 #include "statedump.h"
 #include "upcall-utils.h"
-#include "tw.h"
 
 static void
 nlc_dentry_op (call_frame_t *frame, xlator_t *this, gf_boolean_t multilink)
@@ -627,6 +626,8 @@ nlc_priv_dump (xlator_t *this)
 void
 fini (xlator_t *this)
 {
+        glusterfs_ctx_tw_put (this->ctx);
+
         return;
 }
 
@@ -702,17 +703,12 @@ init (xlator_t *this)
         INIT_LIST_HEAD (&conf->lru);
         time (&conf->last_child_down);
 
-        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,
-                                NLC_MSG_NO_TIMER_WHEEL,
-                                "Initing the global timer wheel failed");
-                                goto out;
-                }
+        conf->timer_wheel = glusterfs_ctx_tw_get (this->ctx);
+        if (!conf->timer_wheel) {
+                gf_msg (this->name, GF_LOG_ERROR, 0, NLC_MSG_NO_TIMER_WHEEL,
+                        "Initing the global timer wheel failed");
+                        goto out;
         }
-        conf->timer_wheel = glusterfs_global_timer_wheel (this);
 
         this->private = conf;