[Xen-devel] [PATCH][1/4][IOMGR] I/O request Manager body

["Satoshi Uchida" <s-uchida@xxxxxxxxxxxxx>]

This patch provides a I/O request management framework.

This framework can control virtual block device threads at 7 places :
  * deciding that virtual block devices(threads) is ether going or waiting,
  * before allocating pending_request variables,
  * after allocated pending_request variables,
  * after allocated no pending_request variables (Namely, out of request),
  * after freed pending_request variables and
  * starting/stopping virtual block devices(threads).

And, iomgr provides the total number of pending requests in blkback and blktap.

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


# HG changeset patch
# User s-uchida@xxxxxxxxxxxxx
# Date 1184302359 -32400
# Node ID aee77a9230c1b19873e60761d080af517bbfb189
# Parent  e64625df946b81ac1a5f8be7c5d0ae2aad618d7c
[IOMGR] Add I/O request management framework.
  This is body for I/O request management.

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

diff -r e64625df946b -r aee77a9230c1 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
@@ -65,6 +65,15 @@ config XEN_BLKDEV_TAP
           high-performance block backends, where disk images may be implemented
           as files, in memory, or on other hosts across the network.  This 
          driver can safely coexist with the existing blockback driver.
+
+config XEN_IOMGR
+       tristate "Backend I/O request manager framework"
+       depends on XEN_BACKEND || XEN_BLKDEV_TAP
+       default y
+       help
+         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_NETDEV_BACKEND
        tristate "Network-device backend driver"
diff -r e64625df946b -r aee77a9230c1 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
@@ -10,6 +10,7 @@ obj-y += util.o
 obj-y  += util.o
 obj-$(CONFIG_XEN_BLKDEV_BACKEND)       += blkback/
 obj-$(CONFIG_XEN_BLKDEV_TAP)           += blktap/
+obj-$(CONFIG_XEN_IOMGR)                        += iomgr/
 obj-$(CONFIG_XEN_NETDEV_BACKEND)       += netback/
 obj-$(CONFIG_XEN_TPMDEV_BACKEND)       += tpmback/
 obj-$(CONFIG_XEN_BLKDEV_FRONTEND)      += blkfront/
diff -r e64625df946b -r aee77a9230c1 drivers/xen/iomgr/Makefile
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/xen/iomgr/Makefile        Fri Jul 13 13:52:39 2007 +0900
@@ -0,0 +1,4 @@
+obj-$(CONFIG_XEN_IOMGR) := xeniomgr.o
+
+xeniomgr-y := iomgr.o
+
diff -r e64625df946b -r aee77a9230c1 drivers/xen/iomgr/iomgr.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/xen/iomgr/iomgr.c Fri Jul 13 13:52:39 2007 +0900
@@ -0,0 +1,188 @@
+/*****************************************************************************
+ * iomgr.c
+ *
+ *  Management interface for I/O request.
+ *
+ * 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/module.h>
+#include <linux/stddef.h>
+#include <xen/iomgr.h>
+#include <asm/atomic.h>
+
+/* Current manager. */
+struct iomgr *mgr;
+
+/*
+ *  Default Manager.
+ *  Non Management for I/O request.
+ */
+static struct iomgr nomgr = {
+       .ops = {
+               .iomgr_waiting_request_fn = NULL,
+               .iomgr_allow_request_fn = NULL,
+               .iomgr_alloc_request_fn = NULL,
+               .iomgr_oo_abort_request_fn = NULL,
+               .iomgr_free_request_fn = NULL,
+               .iomgr_dev_start_fn = NULL,
+               .iomgr_dev_stop_fn = NULL,
+       },
+       .iomgr_name = "none",
+};
+
+/*
+ *  Counter for pending request.
+ */
+atomic_t pending_req = ATOMIC_INIT(0);
+
+
+/*
+ *  Functions which apply iomgr operations
+ */
+
+/*
+ *  Management for original waiting condition within VBD/TAP thread.
+ */
+int do_iomgr_waiting_request(struct xenbus_device *dev)
+{
+       if (mgr->ops.iomgr_waiting_request_fn != NULL)
+               return mgr->ops.iomgr_waiting_request_fn(dev);
+       else
+               return 0;
+}
+
+/*
+ *  Management when new request for VBD/TAP thread is securing.
+ */
+int do_iomgr_allow_request(struct xenbus_device *dev)
+{
+       if (mgr->ops.iomgr_allow_request_fn != NULL)
+               return mgr->ops.iomgr_allow_request_fn(dev);
+       else
+               return 0;
+}
+
+/* Management of allocating new request for VBD/TAP thread. */
+int do_iomgr_alloc_request(struct xenbus_device *dev)
+{
+       atomic_inc(&pending_req);
+       if (mgr->ops.iomgr_alloc_request_fn != NULL)
+               return mgr->ops.iomgr_alloc_request_fn(dev);
+       else
+               return 0;
+}
+
+/*
+ *  Management when it is failure to allocating new request
+ *  for VBD/TAP thread.
+ */
+int do_iomgr_oo_abort_request(struct xenbus_device *dev)
+{
+       if (mgr->ops.iomgr_oo_abort_request_fn != NULL)
+               return mgr->ops.iomgr_oo_abort_request_fn(dev);
+       else
+               return 0;
+}
+
+/*
+ *  Management when request for VBD/TAP thread finishes.
+ */
+void do_iomgr_free_request(struct xenbus_device *dev)
+{
+       atomic_dec(&pending_req);
+       if (mgr->ops.iomgr_free_request_fn != NULL)
+               mgr->ops.iomgr_free_request_fn(dev);
+}
+
+/*
+ *  Management when new VBD/TAP thread start.
+ */
+int do_iomgr_dev_start(struct xenbus_device *dev)
+{
+       if (mgr->ops.iomgr_dev_start_fn != NULL)
+               return mgr->ops.iomgr_dev_start_fn(dev);
+       return 0;
+}
+
+/*
+ *  Management when VBD/TAP thread stops.
+ */
+void do_iomgr_dev_stop(struct xenbus_device *dev)
+{
+       if (mgr->ops.iomgr_dev_stop_fn != NULL)
+               mgr->ops.iomgr_dev_stop_fn(dev);
+}
+
+
+/* Access to counter for pending requests. */
+atomic_t *num_pending_req(void)
+{
+       return &pending_req;
+}
+EXPORT_SYMBOL(num_pending_req);
+
+
+/*
+ *  Registration function for I/O manager.
+ */
+
+/* Registration of I/O Manager.*/
+int xen_iomgr_register(struct iomgr *newmgr)
+{
+       mgr = newmgr;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(xen_iomgr_register);
+
+/*
+ * Unregistration of I/O Manager.
+ * Change to No operation manager.
+ */
+void xen_iomgr_unregister(struct iomgr *removemgr)
+{
+       if (mgr == removemgr)
+               mgr = &nomgr;
+}
+EXPORT_SYMBOL_GPL(xen_iomgr_unregister);
+
+
+/* Initializing function */
+static int iomgr_init(void)
+{
+       mgr = &nomgr;
+
+       return 0;
+}
+
+
+module_init(iomgr_init);
+
+MODULE_AUTHOR("Satoshi UCHIDA");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("Xen IO Manager");
diff -r e64625df946b -r aee77a9230c1 include/xen/iomgr.h
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/include/xen/iomgr.h       Fri Jul 13 13:52:39 2007 +0900
@@ -0,0 +1,100 @@
+/*****************************************************************************
+ * iomgr.h
+ *
+ *  Management interface for I/O request.
+ *
+ * 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.
+ */
+
+#ifndef _XEN_IOMER_H
+#define _XEN_IOMER_H
+
+#include <asm/atomic.h>
+
+#define IOMGR_ALLOW_NG  1
+
+struct xenbus_device;
+
+/*
+ * Definition of iomgr function.
+ */
+typedef int (iomgr_waiting_request_fn) (struct xenbus_device *);
+typedef int (iomgr_allow_request_fn) (struct xenbus_device *);
+typedef int (iomgr_alloc_request_fn) (struct xenbus_device *);
+typedef int (iomgr_oo_abort_request_fn) (struct xenbus_device *);
+typedef void (iomgr_free_request_fn) (struct xenbus_device *);
+typedef int (iomgr_dev_start_fn) (struct xenbus_device *);
+typedef void (iomgr_dev_stop_fn) (struct xenbus_device *);
+
+
+/* iomgr operations */
+struct iomgr_ops
+{
+       iomgr_waiting_request_fn   *iomgr_waiting_request_fn;
+       iomgr_allow_request_fn     *iomgr_allow_request_fn;
+       iomgr_alloc_request_fn     *iomgr_alloc_request_fn;
+       iomgr_oo_abort_request_fn  *iomgr_oo_abort_request_fn;
+       iomgr_free_request_fn      *iomgr_free_request_fn;
+       iomgr_dev_start_fn         *iomgr_dev_start_fn;
+       iomgr_dev_stop_fn          *iomgr_dev_stop_fn;
+};
+
+#define IOMGR_NAME_MAX    (16)
+
+
+/* iomgr scheduler structure */
+struct iomgr
+{
+       struct iomgr_ops ops;
+       char iomgr_name[IOMGR_NAME_MAX];
+};
+
+
+/*
+ *  functions which apply iomgr operations
+ */
+int do_iomgr_waiting_request(struct xenbus_device *dev);
+int do_iomgr_allow_request(struct xenbus_device *dev);
+int do_iomgr_alloc_request(struct xenbus_device *dev);
+int do_iomgr_oo_abort_request(struct xenbus_device *dev);
+void do_iomgr_free_request(struct xenbus_device *dev);
+int do_iomgr_dev_start(struct xenbus_device *dev);
+void do_iomgr_dev_stop(struct xenbus_device *dev);
+
+/*
+ *  pending rezuest counter
+ */ 
+atomic_t *num_pending_req(void);
+
+
+/*
+ * Xen I/O scheduler registration
+ */
+extern int xen_iomgr_register(struct iomgr *);
+extern void xen_iomgr_unregister(struct iomgr *);
+       
+#endif


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