kevent: Timer notifications.

Timer notifications.

Timer notifications can be used for fine grained per-process
time 
management, since interval timers are very inconvenient to
use, 
and they are limited.

Signed-off-by: Evgeniy Polyakov <johnpol2ka.mitp.ru>

diff --git a/kernel/kevent/kevent_timer.c
b/kernel/kevent/kevent_timer.c
new file mode 100644
index 0000000..04acc46
--- /dev/null
+++ b/kernel/kevent/kevent_timer.c
 -0,0
+1,113 
+/*
+ * 2006 Copyright (c) Evgeniy Polyakov <johnpol2ka.mipt.ru>
+ * All rights reserved.
+ *
+ * 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; if not, write to the Free
Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/hrtimer.h>
+#include <linux/jiffies.h>
+#include <linux/kevent.h>
+
+struct kevent_timer
+{
+	struct hrtimer		ktimer;
+	struct kevent_storage	ktimer_storage;
+	struct kevent		*ktimer_event;
+};
+
+static int kevent_timer_func(struct hrtimer *timer)
+{
+	struct kevent_timer *t = container_of(timer, struct
kevent_timer, ktimer);
+	struct kevent *k = t->ktimer_event;
+
+	kevent_storage_ready(&t->ktimer_storage, NULL,
KEVENT_MASK_ALL);
+	hrtimer_forward(timer, timer->base->softirq_time,
+			ktime_set(k->event.id.raw[0],
k->event.id.raw[1]));
+	return HRTIMER_RESTART;
+}
+
+static struct lock_class_key kevent_timer_key;
+
+static int kevent_timer_enqueue(struct kevent *k)
+{
+	int err;
+	struct kevent_timer *t;
+
+	t = kmalloc(sizeof(struct kevent_timer), GFP_KERNEL);
+	if (!t)
+		return -ENOMEM;
+
+	hrtimer_init(&t->ktimer, CLOCK_MONOTONIC,
HRTIMER_REL);
+	t->ktimer.expires = ktime_set(k->event.id.raw[0],
k->event.id.raw[1]);
+	t->ktimer.function = kevent_timer_func;
+	t->ktimer_event = k;
+
+	err = kevent_storage_init(&t->ktimer,
&t->ktimer_storage);
+	if (err)
+		goto err_out_free;
+	lockdep_set_class(&t->ktimer_storage.lock,
&kevent_timer_key);
+
+	err = kevent_storage_enqueue(&t->ktimer_storage,
k);
+	if (err)
+		goto err_out_st_fini;
+
+	printk("%s: jiffies: %lu, timer: %p.\n",
__func__, jiffies, &t->ktimer);
+	hrtimer_start(&t->ktimer, t->ktimer.expires,
HRTIMER_REL);
+
+	return 0;
+
+err_out_st_fini:
+	kevent_storage_fini(&t->ktimer_storage);
+err_out_free:
+	kfree(t);
+
+	return err;
+}
+
+static int kevent_timer_dequeue(struct kevent *k)
+{
+	struct kevent_storage *st = k->st;
+	struct kevent_timer *t = container_of(st, struct
kevent_timer, ktimer_storage);
+
+	hrtimer_cancel(&t->ktimer);
+	kevent_storage_dequeue(st, k);
+	kfree(t);
+
+	return 0;
+}
+
+static int kevent_timer_callback(struct kevent *k)
+{
+	k->event.ret_data[0] = jiffies_to_msecs(jiffies);
+	return 1;
+}
+
+static int __init kevent_init_timer(void)
+{
+	struct kevent_callbacks tc = {
+		.callback = &kevent_timer_callback,
+		.enqueue = &kevent_timer_enqueue,
+		.dequeue = &kevent_timer_dequeue};
+
+	return kevent_add_callbacks(&tc, KEVENT_TIMER);
+}
+module_init(kevent_init_timer);
+

-
To unsubscribe from this list: send the line
"unsubscribe linux-kernel" in
the body of a message to majordomovger.kernel.org
More majordomo info at  http://vge
r.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

kevent: Timer notifications.

Thread: kevent: Timer notifications.