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, 38 insertions, 1 deletions

diff --git a/libglusterfs/src/ctx.c b/libglusterfs/src/ctx.c
index d3fb39822d1..1c707eb5dfd 100644
--- a/libglusterfs/src/ctx.c
+++ b/libglusterfs/src/ctx.c
@@ -9,9 +9,10 @@
 */
 
 #include <pthread.h>
-#include "globals.h"
 
+#include "globals.h"
 #include "glusterfs.h"
+#include "timer-wheel.h"
 
 glusterfs_ctx_t *
 glusterfs_ctx_new ()
@@ -52,3 +53,39 @@ out:
 	return ctx;
 }
 
+static void
+glusterfs_ctx_tw_destroy (struct gf_ctx_tw *ctx_tw)
+{
+        if (ctx_tw->timer_wheel)
+                gf_tw_cleanup_timers (ctx_tw->timer_wheel);
+
+        GF_FREE (ctx_tw);
+}
+
+struct tvec_base*
+glusterfs_ctx_tw_get (glusterfs_ctx_t *ctx)
+{
+        struct gf_ctx_tw *ctx_tw = NULL;
+
+        LOCK (&ctx->lock);
+        {
+                if (ctx->tw) {
+                        ctx_tw = GF_REF_GET (ctx->tw);
+                } else {
+                        ctx_tw = GF_CALLOC (1, sizeof (struct gf_ctx_tw),
+                                            gf_common_mt_tw_ctx);
+                        ctx_tw->timer_wheel = gf_tw_init_timers();
+                        GF_REF_INIT (ctx_tw, glusterfs_ctx_tw_destroy);
+                        ctx->tw = ctx_tw;
+                }
+        }
+        UNLOCK (&ctx->lock);
+
+        return ctx_tw->timer_wheel;
+}
+
+void
+glusterfs_ctx_tw_put (glusterfs_ctx_t *ctx)
+{
+        GF_REF_PUT (ctx->tw);
+}