core: Global timer-wheel

Instantiate a process wide global instance of the timer wheel
data structure. Spawning glusterfs* process with option arg
"--global-timer-wheel" instantiates a global instance of
timer-wheel under global context (->ctx).

Translators can make use of this process wide instance [via a
call to glusterfs_global_timer_wheel()] instead of maintaining
an instance of their own and possibly consuming more memory.
Linux kernel too has a single instance of timer wheel where
subsystems such as IO, networking, etc.. make use of.

Bitrot daemon would be early consumers of this: bitrot translator
instances for multiple volumes would track objects belonging to
their respective bricks in this global expiry tracking data
structure. This is also a first step to move GlusterFS timer
mechanism to use timer-wheel.

> Change-Id: Ie882df607e07acaced846ea269ebf1ece306d6ae
> BUG: 1170075
> Signed-off-by: Venky Shankar <vshankar@redhat.com>
> Reviewed-on: http://review.gluster.org/10380
> Tested-by: NetBSD Build System
> Reviewed-by: Vijay Bellur <vbellur@redhat.com>
> Tested-by: Gluster Build System <jenkins@build.gluster.com>

Change-Id: I35c840daa9996a059699f8ea5af54c76ede7e09c
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Signed-off-by: Gaurav Kumar Garg <ggarg@redhat.com>
BUG: 1220041
Reviewed-on: http://review.gluster.org/10716
Tested-by: Gluster Build System <jenkins@build.gluster.com>

4 files changed, 59 insertions, 3 deletions

diff --git a/libglusterfs/src/Makefile.am b/libglusterfs/src/Makefile.am
index 6f37e37a878..a9830b4f839 100644
--- a/libglusterfs/src/Makefile.am
+++ b/libglusterfs/src/Makefile.am
@@ -5,7 +5,7 @@ libglusterfs_la_CPPFLAGS = $(GF_CPPFLAGS) -D__USE_FILE_OFFSET64 \
 	-DXLATORDIR=\"$(libdir)/glusterfs/$(PACKAGE_VERSION)/xlator\" \
 	-I$(top_srcdir)/rpc/rpc-lib/src/ -I$(CONTRIBDIR)/rbtree \
 	-I$(CONTRIBDIR)/libexecinfo ${ARGP_STANDALONE_CPPFLAGS} \
-	-DSBIN_DIR=\"$(sbindir)\"
+	-DSBIN_DIR=\"$(sbindir)\" -I$(CONTRIBDIR)/timer-wheel
 
 libglusterfs_la_LIBADD = @LEXLIB@ $(ZLIB_LIBS) $(MATH_LIB) $(UUID_LIBS)
 libglusterfs_la_LDFLAGS = -version-info $(LIBGLUSTERFS_LT_VERSION)
@@ -28,7 +28,7 @@ libglusterfs_la_SOURCES = dict.c xlator.c logging.c \
 	strfd.c parse-utils.c $(CONTRIBDIR)/mount/mntent.c \
 	$(CONTRIBDIR)/libexecinfo/execinfo.c quota-common-utils.c rot-buffs.c \
 	$(CONTRIBDIR)/timer-wheel/timer-wheel.c \
-	$(CONTRIBDIR)/timer-wheel/find_last_bit.c
+	$(CONTRIBDIR)/timer-wheel/find_last_bit.c tw.c
 
 nodist_libglusterfs_la_SOURCES = y.tab.c graph.lex.c
 
@@ -48,7 +48,7 @@ noinst_HEADERS = common-utils.h defaults.h dict.h glusterfs.h hashfn.h timespec.
 	$(CONTRIBDIR)/libexecinfo/execinfo_compat.h \
 	unittest/unittest.h quota-common-utils.h rot-buffs.h \
 	$(CONTRIBDIR)/timer-wheel/timer-wheel.h compat-uuid.h \
-	upcall-utils.h
+	upcall-utils.h tw.h
 
 if !HAVE_LIBUUID
 # FIXME: unbundle libuuid, see compat-uuid.h.
diff --git a/libglusterfs/src/glusterfs.h b/libglusterfs/src/glusterfs.h
index 3843bb76ed9..228d3203d7a 100644
--- a/libglusterfs/src/glusterfs.h
+++ b/libglusterfs/src/glusterfs.h
@@ -437,6 +437,10 @@ struct _cmd_args {
         int              gid_timeout;
         char             gid_timeout_set;
         int              aux_gfid_mount;
+
+        /* need a process wide timer-wheel? */
+        int              global_timer_wheel;
+
         struct list_head xlator_options;  /* list of xlator_option_t */
 
 	/* fuse options */
@@ -499,6 +503,8 @@ typedef enum {
         MGMT_SSL_ALWAYS
 } mgmt_ssl_t;
 
+struct tvec_base;
+
 struct _glusterfs_ctx {
         cmd_args_t          cmd_args;
         char               *process_uuid;
@@ -573,6 +579,8 @@ struct _glusterfs_ctx {
         pthread_cond_t notify_cond;
         int notifying;
 
+        struct tvec_base *timer_wheel; /* global timer-wheel instance */
+
 };
 typedef struct _glusterfs_ctx glusterfs_ctx_t;
 
diff --git a/libglusterfs/src/tw.c b/libglusterfs/src/tw.c
new file mode 100644
index 00000000000..fa11998aace
--- /dev/null
+++ b/libglusterfs/src/tw.c
@@ -0,0 +1,25 @@
+/*
+  Copyright (c) 2008-2015 Red Hat, Inc. <http://www.redhat.com>
+  This file is part of GlusterFS.
+
+  This file is licensed to you under your choice of the GNU Lesser
+  General Public License, version 3 or any later version (LGPLv3 or
+  later), or the GNU General Public License, version 2 (GPLv2), in all
+  cases as published by the Free Software Foundation.
+*/
+
+#include "tw.h"
+#include "timer-wheel.h"
+
+int
+glusterfs_global_timer_wheel_init (glusterfs_ctx_t *ctx)
+{
+        ctx->timer_wheel = gf_tw_init_timers();
+        return ctx->timer_wheel ? 0 : -1;
+}
+
+struct tvec_base *
+glusterfs_global_timer_wheel (xlator_t *this)
+{
+        return this->ctx->timer_wheel;
+}
diff --git a/libglusterfs/src/tw.h b/libglusterfs/src/tw.h
new file mode 100644
index 00000000000..e635cd2b496
--- /dev/null
+++ b/libglusterfs/src/tw.h
@@ -0,0 +1,23 @@
+/*
+  Copyright (c) 2008-2015 Red Hat, Inc. <http://www.redhat.com>
+  This file is part of GlusterFS.
+
+  This file is licensed to you under your choice of the GNU Lesser
+  General Public License, version 3 or any later version (LGPLv3 or
+  later), or the GNU General Public License, version 2 (GPLv2), in all
+  cases as published by the Free Software Foundation.
+*/
+
+#ifndef __TW_H__
+#define __TW_H__
+
+#include "xlator.h"
+#include "glusterfs.h"
+
+int
+glusterfs_global_timer_wheel_init (glusterfs_ctx_t *);
+
+struct tvec_base *
+glusterfs_global_timer_wheel (xlator_t *);
+
+#endif /* __TW_H__ */