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, 3 insertions, 3 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;
 }