WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] [PATCH][4/4][IOMGR] Turn-based I/O request scheduler

To: <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] [PATCH][4/4][IOMGR] Turn-based I/O request scheduler
From: "Satoshi Uchida" <s-uchida@xxxxxxxxxxxxx>
Date: Mon, 30 Jul 2007 17:51:23 +0900
Delivery-date: Mon, 30 Jul 2007 01:50:43 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcfShs5zYOlRLLgkTcC7bATyj29lKA==
This patch provides turn-based I/O request scheduler.

The turn-besed I/O scheduler makes virtual block device threads to control I/O 
performance based on the number of reqeusts per "turn".

 --------------------------------------------------
 Satoshi UCHIDA 
    NEC Corporation, Japan


# HG changeset patch
# User s-uchida@xxxxxxxxxxxxx
# Date 1184302442 -32400
# Node ID 216f7a2a56c03aecc08a40ed0f687874f56c89c5
# Parent  aee77a9230c1b19873e60761d080af517bbfb189
[IOMGR] Add the turn-based I/O scheduler.
  This module control I/O request based on the number of request per "turn".

  Signed-off-by  Satoshi UCHIDA <s-uchida@xxxxxxxxxxxxx>

diff -r aee77a9230c1 -r 216f7a2a56c0 drivers/xen/Kconfig
--- a/drivers/xen/Kconfig       Fri Jun 15 13:33:47 2007 -0600
+++ b/drivers/xen/Kconfig       Fri Jul 13 13:45:30 2007 +0900
@@ -74,6 +74,14 @@ config XEN_BLKDEV_TAP
          The Backend I/O request manager framework provides interface
          which makes backend driver to control I/O requests by I/O 
          control modules
+
+config XEN_IOSCHED_TURN
+       tristate "Trun-based I/O request scheduler"
+       depends on XEN_IOMGR
+       default m
+       help
+         The turn-based I/O scheduler controls I/O requests based on the number
+         of requests "per turn".
 
 config XEN_NETDEV_BACKEND
        tristate "Network-device backend driver"
diff -r aee77a9230c1 -r 216f7a2a56c0 drivers/xen/Makefile
--- a/drivers/xen/Makefile      Fri Jun 15 13:33:47 2007 -0600
+++ b/drivers/xen/Makefile      Fri Jul 13 13:45:30 2007 +0900
@@ -11,6 +11,7 @@ obj-y += util.o
 obj-$(CONFIG_XEN_BLKDEV_BACKEND)       += blkback/
 obj-$(CONFIG_XEN_BLKDEV_TAP)           += blktap/
 obj-$(CONFIG_XEN_IOMGR)                        += iomgr/
+obj-$(CONFIG_XEN_IOSCHED_TURN)         += iomgr/
 obj-$(CONFIG_XEN_NETDEV_BACKEND)       += netback/
 obj-$(CONFIG_XEN_TPMDEV_BACKEND)       += tpmback/
 obj-$(CONFIG_XEN_BLKDEV_FRONTEND)      += blkfront/
diff -r aee77a9230c1 -r 216f7a2a56c0 drivers/xen/iomgr/Makefile
+++ a/drivers/xen/iomgr/Makefile        Fri Jul 13 13:52:39 2007 +0900
+++ b/drivers/xen/iomgr/Makefile        Fri Jul 13 13:52:39 2007 +0900
@@ -1,3 +1,4 @@
 
 xeniomgr-y := iomgr.o
 
+obj-$(CONFIG_XEN_IOSCHED_TURN) := turn_iosched.o
diff -r aee77a9230c1 -r 216f7a2a56c0 drivers/xen/iomgr/turn_iosched.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/xen/iomgr/turn_iosched.c  Fri Jul 13 13:54:02 2007 +0900
@@ -0,0 +1,368 @@
+/*****************************************************************************
+ * turn_iosched.c
+ *
+ *  Management stream for I/O request among virtual machines .
+ *  The turn-based I/O scheduler control amount of request in a turn.
+ *
+ * Copyright(c) 2007, Satoshi UCHIDA, NEC Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <asm/atomic.h>
+#include <linux/kthread.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+#include <xen/iomgr.h>
+#include <xen/xenbus.h>
+
+
+static int default_max_cap=64;
+module_param(default_max_cap, int, 644);
+
+static DECLARE_WAIT_QUEUE_HEAD(noncap_wq);
+
+struct hlist_head turn_hash;
+
+
+/* turn scheduler parameter */
+struct turn_data {
+       /* Identification of VBD/TAP device */
+       struct xenbus_device *dev;
+
+        /* capacity updating flag */
+       int update_f;
+
+               /* counting parameter */
+       atomic_t            req_cap;
+       atomic_t            max_cap;
+
+       struct hlist_node   list;
+};
+
+
+/* Find according data to VBD/TAP device. */
+struct turn_data *find_turn_data(struct xenbus_device *dev)
+{
+       struct hlist_head *hash_list = &turn_hash;
+       struct hlist_node *entry;
+       struct turn_data *__data;
+
+       hlist_for_each_entry(__data, entry, hash_list, list) {
+               if (__data->dev == dev)
+                       return __data;
+       }
+
+       return NULL;
+}
+
+
+/* Sysfs Interface */
+static ssize_t show_req_cap(struct device *_dev,
+                           struct device_attribute *attr,
+                           char *buf)
+{
+       struct xenbus_device *dev = to_xenbus_device(_dev);
+       struct turn_data *data = find_turn_data(dev);
+       
+       return sprintf(buf, "%d\n", atomic_read(&data->req_cap));
+}
+
+DEVICE_ATTR(req_cap, S_IRUGO , show_req_cap, NULL);
+
+static ssize_t show_max_cap(struct device *_dev,
+                           struct device_attribute *attr,
+                           char *buf)
+{
+       struct xenbus_device *dev = to_xenbus_device(_dev);
+       struct turn_data *data = find_turn_data(dev);
+       
+       return sprintf(buf, "%d\n", atomic_read(&data->max_cap));
+}
+
+static ssize_t store_max_cap(struct device *_dev,
+                            struct device_attribute *attr,
+                            const char *buf,
+                            size_t count)
+{
+       struct xenbus_device *dev = to_xenbus_device(_dev);
+       struct turn_data *data = find_turn_data(dev);
+       char *endp;
+       int new;
+
+       new = (int)simple_strtoul(buf, &endp, 10);
+       if (endp == buf)
+               return -EINVAL;
+
+       atomic_set(&data->max_cap, new);
+
+       return strnlen(buf, count);
+}
+
+DEVICE_ATTR(max_cap, S_IRUGO | S_IWUSR, show_max_cap, store_max_cap);
+
+static struct attribute *turn_attrs[] = {
+       &dev_attr_req_cap.attr,
+       &dev_attr_max_cap.attr,
+       NULL
+};
+
+static struct attribute_group turn_group = {
+       .name = "iomgr",
+       .attrs = turn_attrs,
+};
+
+int turn_sysfs_addif(struct xenbus_device *dev)
+{
+       int error;
+
+       error = sysfs_create_group(&dev->dev.kobj, &turn_group);
+       if (error)
+               goto fail1;
+
+       return 0;
+
+fail1:  sysfs_remove_group(&dev->dev.kobj, &turn_group);
+
+       return error;
+}
+
+void turn_sysfs_delif(struct xenbus_device *dev)
+{
+       sysfs_remove_group(&dev->dev.kobj, &turn_group);
+}
+
+
+/* Create turn parameter for new VBD/TAP device. */
+struct turn_data *create_turn_data(struct xenbus_device *dev)
+{
+       struct turn_data *data;
+
+       data = kmalloc(sizeof(*data), GFP_KERNEL);
+       if (!data)
+               return NULL;
+
+       memset(data, 0, sizeof(*data));
+
+       data->dev = dev;
+
+       hlist_add_head(&data->list, &turn_hash);
+       atomic_set(&data->max_cap, default_max_cap);
+       data->req_cap = data->max_cap;
+       data->update_f = 0;
+
+       turn_sysfs_addif(dev);
+
+       return data;
+}
+
+
+/* Wake up for original waiting condition. */
+void turn_wake_up(void)
+{
+       struct hlist_head *hash_list = &turn_hash;
+       struct hlist_node *entry;
+       struct turn_data *__data;
+
+       hlist_for_each_entry(__data, entry, hash_list, list) {
+               __data->update_f = 1;
+       }
+       wake_up(&noncap_wq);
+} 
+
+
+/*
+ *   Waiting condition for the turn-based I/O scheduler.
+ *   Wait VBD/TAP thread when it is no capacity.
+ */
+int turn_waiting_request(struct xenbus_device *dev)
+{
+       struct turn_data *data;
+
+       data = find_turn_data(dev);
+       if (!data)
+               return 0;
+
+       if (data->update_f) {
+               data->req_cap = data->max_cap;
+               data->update_f = 0;
+       } else {
+               if (atomic_sub_and_test(0, &data->req_cap)) {
+                       wait_event_interruptible(
+                               noncap_wq,
+                               (data->update_f) ||
+                               hlist_empty(&turn_hash) ||
+                               kthread_should_stop());                 
+                       data->req_cap = data->max_cap;
+                       data->update_f = 0;
+               }
+       }
+       
+       return 0;
+}
+
+
+/*
+ *  Check that VBD/TAP thread have capacity yet.
+ */
+int turn_allow_request(struct xenbus_device *dev)
+{
+       struct turn_data *data;
+
+       data = find_turn_data(dev);
+       if (data == NULL){
+               data = create_turn_data(dev);
+               if (data == NULL) {
+                       printk("FAILED : TURN_IOSCHED : allocating 
paramater\n");
+                       return -ENOMEM;
+               }
+       }
+
+       
+       if (atomic_sub_and_test(0, &data->req_cap)) {
+               return -IOMGR_ALLOW_NG;
+       }
+      
+       return 0;
+}
+
+
+/*
+ *  Decrease VBD/TAP thread capacity, because new request is allocated.
+ */
+int turn_alloc_request(struct xenbus_device *dev) {
+       struct turn_data *data;
+
+       data = find_turn_data(dev);
+       if (!data)
+               return 0;
+
+       atomic_dec(&data->req_cap);
+       return 0;
+}
+
+
+/*
+ *  Wake up, if no request is pending.
+ *  Namely, turn is increase.
+ *  In above case,
+ *    1. all threads no have capacity, or
+ *    2. all threads no have requests which are process as soon as.
+ */
+void turn_free_request(struct xenbus_device *dev)
+{
+       if (atomic_sub_and_test(0, num_pending_req())) {
+               turn_wake_up();
+       }       
+}
+
+
+/*
+ *  Management when VBD/TAP thread starts.
+ */
+int turn_dev_start(struct xenbus_device *dev)
+{
+       struct turn_data *data;
+
+       data = create_turn_data(dev);
+       if (data == NULL) {
+               printk("FAILED : TURN_IOSCHED : allocating paramater\n");
+               return -ENOMEM;
+       }
+
+       return 0;
+}
+
+
+/*
+ *  Management when VBD/TAP thread stops.
+ */
+void turn_dev_stop(struct xenbus_device *dev)
+{
+       struct turn_data *data;
+
+       data = find_turn_data(dev);
+       if (!data)
+               return;
+
+       hlist_del(&data->list);
+       turn_sysfs_delif(data->dev);
+       kfree(data);
+}
+
+
+/*
+ *  Definition of the turn-based I/O scheduler.
+ */ 
+static struct iomgr iomgr_turn = {
+       .ops = {
+               .iomgr_waiting_request_fn   = turn_waiting_request,
+               .iomgr_allow_request_fn     = turn_allow_request,
+               .iomgr_alloc_request_fn     = turn_alloc_request,
+               .iomgr_oo_abort_request_fn  = NULL,
+               .iomgr_free_request_fn      = turn_free_request,
+               .iomgr_dev_start_fn         = turn_dev_start,
+               .iomgr_dev_stop_fn          = turn_dev_stop,
+       },
+       .iomgr_name = "TURN",
+};
+
+
+/* Initializing function. */
+static int __init turn_init(void)
+{      
+       INIT_HLIST_HEAD(&turn_hash);
+       return xen_iomgr_register(&iomgr_turn);
+}
+module_init(turn_init);
+
+
+/* Finishing function. */
+static void __exit turn_exit(void)
+{
+       struct hlist_head *hash_list = &turn_hash;
+       struct hlist_node *entry,*next;
+       struct turn_data *__data;
+
+       xen_iomgr_unregister(&iomgr_turn);
+       hlist_for_each_entry_safe(__data, entry, next, hash_list, list) {
+               if (__data != NULL) {
+                       turn_sysfs_delif(__data->dev);
+                       kfree(__data);
+               }
+       }
+       INIT_HLIST_HEAD(&turn_hash);
+       wake_up(&noncap_wq);
+}
+module_exit(turn_exit);
+
+MODULE_AUTHOR("Satoshi UCHIDA");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("Turn-based IO scheduler");


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>
  • [Xen-devel] [PATCH][4/4][IOMGR] Turn-based I/O request scheduler, Satoshi Uchida <=