MFC geom_sched code, a geom-based disk scheduling framework.

4 files changed, 306 insertions, 0 deletions

diff --git a/sbin/geom/class/Makefile b/sbin/geom/class/Makefile
index 7b556a8..0be19e3 100644
--- a/sbin/geom/class/Makefile
+++ b/sbin/geom/class/Makefile
@@ -14,6 +14,7 @@ SUBDIR+=multipath
 SUBDIR+=nop
 SUBDIR+=part
 SUBDIR+=raid3
+SUBDIR+=sched
 SUBDIR+=shsec
 SUBDIR+=stripe
 SUBDIR+=virstor
diff --git a/sbin/geom/class/sched/Makefile b/sbin/geom/class/sched/Makefile
new file mode 100644
index 0000000..6656cdd
--- /dev/null
+++ b/sbin/geom/class/sched/Makefile
@@ -0,0 +1,18 @@
+# GEOM_LIBRARY_PATH
+# $FreeBSD$
+
+.PATH: ${.CURDIR}/../../misc
+#CFLAGS += -I/usr/src/sbin/geom
+
+CLASS=sched
+
+WARNS?= 6
+CLASS_DIR?=/lib/geom
+
+SHLIBDIR?=${CLASS_DIR}
+SHLIB_NAME?=geom_${CLASS}.so
+LINKS=  ${BINDIR}/geom ${BINDIR}/g${CLASS}
+MAN=    g${CLASS}.8
+SRCS+=  geom_${CLASS}.c subr.c
+
+.include <bsd.lib.mk>
diff --git a/sbin/geom/class/sched/geom_sched.c b/sbin/geom/class/sched/geom_sched.c
new file mode 100644
index 0000000..ca05350
--- /dev/null
+++ b/sbin/geom/class/sched/geom_sched.c
@@ -0,0 +1,124 @@
+/*-
+ * Copyright (c) 2009 Fabio Checconi
+ * Copyright (c) 2010 Luigi Rizzo, Universita` di Pisa
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * $Id$
+ * $FreeBSD$
+ *
+ * This file implements the userspace library used by the 'geom'
+ * command to load and manipulate disk schedulers.
+ */
+  
+#include <sys/cdefs.h>
+#include <sys/param.h>
+#include <sys/linker.h>
+#include <sys/module.h>
+
+#include <stdio.h>
+#include <stdint.h>
+#include <libgeom.h>
+
+#include "core/geom.h"
+#include "misc/subr.h"
+
+#define	G_SCHED_VERSION	0
+
+uint32_t lib_version = G_LIB_VERSION;
+uint32_t version = G_SCHED_VERSION;
+
+/*
+ * storage for parameters used by this geom class.
+ * Right now only the scheduler name is used.
+ */
+static char algo[] = "rr";	/* default scheduler */
+
+/*
+ * Adapt to differences in geom library.
+ * in V1 struct g_command misses gc_argname, eld, and G_BOOL is undefined
+ */
+#if G_LIB_VERSION == 1
+#define G_ARGNAME
+#define G_TYPE_BOOL	G_TYPE_NUMBER
+#else
+#define G_ARGNAME	NULL,
+#endif
+
+static void
+gcmd_createinsert(struct gctl_req *req, unsigned flags __unused)
+{
+	const char *reqalgo;
+	char name[64];
+
+	if (gctl_has_param(req, "algo"))
+		reqalgo = gctl_get_ascii(req, "algo");
+	else
+		reqalgo = algo;
+
+	snprintf(name, sizeof(name), "gsched_%s", reqalgo);
+	/*
+	 * Do not complain about errors here, gctl_issue()
+	 * will fail anyway.
+	 */
+	if (modfind(name) < 0)
+		kldload(name);
+	gctl_issue(req);
+}
+
+struct g_command class_commands[] = {
+	{ "create", G_FLAG_VERBOSE | G_FLAG_LOADKLD, gcmd_createinsert,
+	    {
+		{ 'a', "algo", algo, G_TYPE_STRING },
+		G_OPT_SENTINEL
+	    },
+	    G_ARGNAME "[-v] [-a algorithm_name] dev ..."
+	},
+	{ "insert", G_FLAG_VERBOSE | G_FLAG_LOADKLD, gcmd_createinsert,
+	    {
+		{ 'a', "algo", algo, G_TYPE_STRING },
+		G_OPT_SENTINEL
+	    },
+	    G_ARGNAME "[-v] [-a algorithm_name] dev ..."
+	},
+	{ "configure", G_FLAG_VERBOSE, NULL,
+	    {
+		{ 'a', "algo", algo, G_TYPE_STRING },
+		G_OPT_SENTINEL
+	    },
+	    G_ARGNAME "[-v] [-a algorithm_name] prov ..."
+	},
+	{ "destroy", G_FLAG_VERBOSE, NULL,
+	    {
+		{ 'f', "force", NULL, G_TYPE_BOOL },
+		G_OPT_SENTINEL
+	    },
+	    G_ARGNAME "[-fv] prov ..."
+	},
+	{ "reset", G_FLAG_VERBOSE, NULL, G_NULL_OPTS,
+	    G_ARGNAME "[-v] prov ..."
+	},
+	G_CMD_SENTINEL
+};
diff --git a/sbin/geom/class/sched/gsched.8 b/sbin/geom/class/sched/gsched.8
new file mode 100644
index 0000000..cde9485
--- /dev/null
+++ b/sbin/geom/class/sched/gsched.8
@@ -0,0 +1,163 @@
+.\" Copyright (c) 2009-2010 Fabio Checconi
+.\" Copyright (c) 2009-2010 Luigi Rizzo, Universita` di Pisa
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd April 12, 2010
+.Dt GSCHED 8
+.Os
+.Sh NAME
+.Nm gsched
+.Nd "control utility for disk scheduler GEOM class"
+.Sh SYNOPSIS
+.Nm
+.Cm create
+.Op Fl v
+.Op Fl a Ar algorithm
+.Ar provider ...
+.Nm
+.Cm insert
+.Op Fl v
+.Op Fl a Ar algorithm
+.Ar provider ...
+.Nm
+.Cm configure
+.Op Fl v
+.Op Fl a Ar algorithm
+.Ar node ...
+.Nm
+.Cm destroy
+.Op Fl fv
+.Ar node ...
+.Nm
+.Cm reset
+.Op Fl v
+.Ar node ...
+.Nm
+.Cm { list | status | load | unload }
+.Sh DESCRIPTION
+The
+.Nm
+utility (also callable as
+.Nm geom sched ... )
+changes the scheduling policy of the requests going to a provider.
+.Pp
+The first argument to
+.Nm
+indicates an action to be performed:
+.Bl -tag -width ".Cm configure"
+.It Cm create
+Create a new provider and geom node using the specified scheduling algorithm.
+.Ar algorithm
+is the name of the scheduling algorithm used for the provider.
+Available algorithms include:
+.Ar rr ,
+which implements anticipatory scheduling with round robin service
+among clients;
+.Ar as ,
+which implements a simple form of anticipatory scheduling with
+no per-client queue.
+.Pp
+If the operation succeeds, the new provider should appear with name
+.Pa /dev/ Ns Ao Ar dev Ac Ns Pa .sched. .
+The kernel module
+.Pa geom_sched.ko
+will be loaded if it is not loaded already.
+.It Cm insert
+Operates as "create", but the insertion is "transparent",
+i.e. the existing provider is rerouted to the newly created geom,
+which in turn forwards requests to the existing geom.
+This operation allows one to start/stop a scheduling service
+on an already existing provider.
+.Pp
+A subsequent 'destroy' will remove the newly created geom and
+hook the provider back to the original geom.
+.Ar algorithm
+.It Cm configure
+Configure existing scheduling provider.  It supports the same options
+as the 
+.Nm create
+command.
+.It Cm destroy
+Destroy the geom specified in the parameter.
+.It Cm reset
+Do nothing.
+.It Cm list | status | load | unload
+See
+.Xr geom 8 .
+.El
+.Pp
+Additional options:
+.Bl -tag -width ".Fl f"
+.It Fl f
+Force the removal of the specified provider.
+.It Fl v
+Be more verbose.
+.El
+.Sh SYSCTL VARIABLES
+The following
+.Xr sysctl 8
+variables can be used to control the behavior of the
+.Nm SCHED
+GEOM class.
+The default value is shown next to each variable.
+.Bl -tag -width indent
+.It Va kern.geom.sched.debug : No 0
+Debug level of the
+.Nm SCHED
+GEOM class.
+This can be set to a number between 0 and 2 inclusive.
+If set to 0 minimal debug information is printed, and if set to 2 the
+maximum amount of debug information is printed.
+.El
+.Sh EXIT STATUS
+Exit status is 0 on success, and 1 if the command fails.
+.Sh EXAMPLES
+The following example shows how to create a scheduling provider for disk
+.Pa /dev/da0
+, and how to destroy it.
+.Bd -literal -offset indent
+# Load the geom_sched module:
+kldload geom_sched
+# Load some scheduler classes used by geom_sched:
+kldload gsched_rr gsched_as
+# Configure device ad0 to use scheduler 'rr':
+geom sched insert -s rr ad0
+# Now provider ad0 uses the 'rr' algorithm;
+# the new geom is ad0.sched.
+# Remove the scheduler on the device:
+geom sched destroy -v ad0.sched.
+.Ed
+.Pp
+.Sh SEE ALSO
+.Xr geom 4 ,
+.Xr geom 8
+.Sh HISTORY
+The
+.Nm
+utility appeared in April 2010.
+.Sh AUTHORS
+.An Fabio Checconi Aq fabio@FreeBSD.org
+.An Luigi Rizzo Aq luigi@FreeBSD.org