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-rw-r--r--lib/wheel.c162
1 files changed, 162 insertions, 0 deletions
diff --git a/lib/wheel.c b/lib/wheel.c
new file mode 100644
index 0000000..6e9c88d
--- /dev/null
+++ b/lib/wheel.c
@@ -0,0 +1,162 @@
+/*
+ * Timer Wheel
+ * Copyright (C) 2016 Cumulus Networks, Inc.
+ * Donald Sharp
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include "zebra.h"
+#include "linklist.h"
+#include "thread.h"
+#include "memory.h"
+#include "wheel.h"
+#include "log.h"
+
+DEFINE_MTYPE_STATIC(LIB, TIMER_WHEEL, "Timer Wheel");
+DEFINE_MTYPE_STATIC(LIB, TIMER_WHEEL_LIST, "Timer Wheel Slot List");
+
+static int debug_timer_wheel = 0;
+
+static void wheel_timer_thread(struct thread *t);
+
+static void wheel_timer_thread_helper(struct thread *t)
+{
+ struct listnode *node, *nextnode;
+ unsigned long long curr_slot;
+ unsigned int slots_to_skip = 1;
+ struct timer_wheel *wheel;
+ void *data;
+
+ wheel = THREAD_ARG(t);
+
+ wheel->curr_slot += wheel->slots_to_skip;
+
+ curr_slot = wheel->curr_slot % wheel->slots;
+
+ if (debug_timer_wheel)
+ zlog_debug("%s: Wheel Slot: %lld(%lld) count: %d", __func__,
+ wheel->curr_slot, curr_slot,
+ listcount(wheel->wheel_slot_lists[curr_slot]));
+
+ for (ALL_LIST_ELEMENTS(wheel->wheel_slot_lists[curr_slot], node,
+ nextnode, data))
+ (*wheel->slot_run)(data);
+
+ while (list_isempty(wheel->wheel_slot_lists[(curr_slot + slots_to_skip)
+ % wheel->slots])
+ && (curr_slot + slots_to_skip) % wheel->slots != curr_slot)
+ slots_to_skip++;
+
+ wheel->slots_to_skip = slots_to_skip;
+ thread_add_timer_msec(wheel->master, wheel_timer_thread, wheel,
+ wheel->nexttime * slots_to_skip, &wheel->timer);
+}
+
+static void wheel_timer_thread(struct thread *t)
+{
+ struct timer_wheel *wheel;
+
+ wheel = THREAD_ARG(t);
+
+ thread_execute(wheel->master, wheel_timer_thread_helper, wheel, 0);
+}
+
+struct timer_wheel *wheel_init(struct thread_master *master, int period,
+ size_t slots, unsigned int (*slot_key)(const void *),
+ void (*slot_run)(void *),
+ const char *run_name)
+{
+ struct timer_wheel *wheel;
+ size_t i;
+
+ wheel = XCALLOC(MTYPE_TIMER_WHEEL, sizeof(struct timer_wheel));
+
+ wheel->name = XSTRDUP(MTYPE_TIMER_WHEEL, run_name);
+ wheel->slot_key = slot_key;
+ wheel->slot_run = slot_run;
+
+ wheel->period = period;
+ wheel->slots = slots;
+ wheel->curr_slot = 0;
+ wheel->master = master;
+ wheel->nexttime = period / slots;
+
+ wheel->wheel_slot_lists = XCALLOC(MTYPE_TIMER_WHEEL_LIST,
+ slots * sizeof(struct list *));
+ for (i = 0; i < slots; i++)
+ wheel->wheel_slot_lists[i] = list_new();
+
+ thread_add_timer_msec(wheel->master, wheel_timer_thread, wheel,
+ wheel->nexttime, &wheel->timer);
+
+ return wheel;
+}
+
+void wheel_delete(struct timer_wheel *wheel)
+{
+ int i;
+
+ for (i = 0; i < wheel->slots; i++) {
+ list_delete(&wheel->wheel_slot_lists[i]);
+ }
+
+ THREAD_OFF(wheel->timer);
+ XFREE(MTYPE_TIMER_WHEEL_LIST, wheel->wheel_slot_lists);
+ XFREE(MTYPE_TIMER_WHEEL, wheel->name);
+ XFREE(MTYPE_TIMER_WHEEL, wheel);
+}
+
+int wheel_stop(struct timer_wheel *wheel)
+{
+ THREAD_OFF(wheel->timer);
+ return 0;
+}
+
+int wheel_start(struct timer_wheel *wheel)
+{
+ if (!wheel->timer)
+ thread_add_timer_msec(wheel->master, wheel_timer_thread, wheel,
+ wheel->nexttime, &wheel->timer);
+
+ return 0;
+}
+
+int wheel_add_item(struct timer_wheel *wheel, void *item)
+{
+ long long slot;
+
+ slot = (*wheel->slot_key)(item);
+
+ if (debug_timer_wheel)
+ zlog_debug("%s: Inserting %p: %lld %lld", __func__, item, slot,
+ slot % wheel->slots);
+ listnode_add(wheel->wheel_slot_lists[slot % wheel->slots], item);
+
+ return 0;
+}
+
+int wheel_remove_item(struct timer_wheel *wheel, void *item)
+{
+ long long slot;
+
+ slot = (*wheel->slot_key)(item);
+
+ if (debug_timer_wheel)
+ zlog_debug("%s: Removing %p: %lld %lld", __func__, item, slot,
+ slot % wheel->slots);
+ listnode_delete(wheel->wheel_slot_lists[slot % wheel->slots], item);
+
+ return 0;
+}