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>

contrib/timer-wheel/timer-wheel.c

@@ -17,6 +17,9 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/select.h>
 
 #include "timer-wheel.h"
 

glusterfsd/src/glusterfsd.c

@@ -74,6 +74,7 @@
 #include "exports.h"
 
 #include "daemon.h"
+#include "tw.h"
 
 /* process mode definitions */
 #define GF_SERVER_PROCESS   0
@@ -184,6 +185,8 @@ static struct argp_option gf_options[] = {
          "Brick Port to be registered with Gluster portmapper" },
 	{"fopen-keep-cache", ARGP_FOPEN_KEEP_CACHE_KEY, "BOOL", OPTION_ARG_OPTIONAL,
 	 "Do not purge the cache on file open"},
+        {"global-timer-wheel", ARGP_GLOBAL_TIMER_WHEEL, "BOOL",
+         OPTION_ARG_OPTIONAL, "Instantiate process global timer-wheel"},
 
         {0, 0, 0, 0, "Fuse options:"},
         {"direct-io-mode", ARGP_DIRECT_IO_MODE_KEY, "BOOL", OPTION_ARG_OPTIONAL,
@@ -1065,6 +1068,10 @@ parse_opts (int key, char *arg, struct argp_state *state)
 
 		break;
 
+        case ARGP_GLOBAL_TIMER_WHEEL:
+                cmd_args->global_timer_wheel = 1;
+                break;
+
 	case ARGP_GID_TIMEOUT_KEY:
 		if (!gf_string2int(arg, &cmd_args->gid_timeout)) {
 			cmd_args->gid_timeout_set = _gf_true;
@@ -2218,7 +2225,6 @@ out:
         return ret;
 }
 
-
 /* This is the only legal global pointer  */
 glusterfs_ctx_t *glusterfsd_ctx;
 
@@ -2306,6 +2312,13 @@ main (int argc, char *argv[])
                 goto out;
         }
 
+        /* do this _after_ deamonize() */
+        if (cmd->global_timer_wheel) {
+                ret = glusterfs_global_timer_wheel_init (ctx);
+                if (ret)
+                        goto out;
+        }
+
         ret = glusterfs_volumes_init (ctx);
         if (ret)
                 goto out;

glusterfsd/src/glusterfsd.h

@@ -94,6 +94,7 @@ enum argp_option_keys {
         ARGP_LOG_BUF_SIZE                 = 170,
         ARGP_LOG_FLUSH_TIMEOUT            = 171,
         ARGP_SECURE_MGMT_KEY              = 172,
+        ARGP_GLOBAL_TIMER_WHEEL           = 173,
 };
 
 struct _gfd_vol_top_priv_t {

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
 
@@ -47,7 +47,8 @@ noinst_HEADERS = common-utils.h defaults.h dict.h glusterfs.h hashfn.h timespec.
 	$(CONTRIBDIR)/mount/mntent_compat.h lvm-defaults.h \
 	$(CONTRIBDIR)/libexecinfo/execinfo_compat.h \
 	unittest/unittest.h quota-common-utils.h rot-buffs.h \
-	$(CONTRIBDIR)/timer-wheel/timer-wheel.h compat-uuid.h
+	$(CONTRIBDIR)/timer-wheel/timer-wheel.h compat-uuid.h \
+	tw.h
 
 if !HAVE_LIBUUID
 # FIXME: unbundle libuuid, see compat-uuid.h.

libglusterfs/src/glusterfs.h

@@ -434,6 +434,10 @@ 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 */
@@ -496,6 +500,8 @@ typedef enum {
         MGMT_SSL_ALWAYS
 } mgmt_ssl_t;
 
+struct tvec_base;
+
 struct _glusterfs_ctx {
         cmd_args_t          cmd_args;
         char               *process_uuid;
@@ -570,6 +576,8 @@ 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;
 

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;
+}

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__ */