Mailing List Archive

[PATCH 03/06]


Introduces the kobjects associated to each tunable and the sysfs registration


Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>


---
include/linux/akt.h | 25 ++++-
init/main.c | 1
kernel/autotune/Makefile | 2
kernel/autotune/akt.c | 91 ++++++++++++++++++
kernel/autotune/akt_sysfs.c | 214 ++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 330 insertions(+), 3 deletions(-)

Index: linux-2.6.20-rc4/include/linux/akt.h
===================================================================
--- linux-2.6.20-rc4.orig/include/linux/akt.h 2007-01-29 15:07:54.000000000 +0100
+++ linux-2.6.20-rc4/include/linux/akt.h 2007-01-29 15:32:48.000000000 +0100
@@ -48,6 +48,16 @@ typedef int (*auto_tune_fn)(int, struct


/*
+ * for sysfs support
+ */
+struct tunable_kobject {
+ struct kobject kobj;
+ struct auto_tune *tun;
+};
+
+
+
+/*
* Structure used to describe the min / max values for a tunable inside the
* auto_tune structure.
*/
@@ -62,7 +72,12 @@ struct tunable_limit {
* allocated for each registered tunable, and the associated kobject exported
* via sysfs.
*
- * The structure lock (tunable_lck) protects
+ * This structure may be accessed in 2 ways:
+ * . directly from inside the kernel susbsystem that uses it (during tunable
+ * automatic adjustment)
+ * . from sysfs, while updating the kobject attributes
+ *
+ * In both cases, the structure lock (tunable_lck) is taken: it protects
* against concurrent accesses to tunable and checked pointers
*
* A pointer to this structure is passed in to the automatic adjustment
@@ -92,6 +107,7 @@ struct auto_tune {
/* reach */
struct tunable_limit max; /* max value the tunable can ever */
/* reach */
+ struct tunable_kobject tun_kobj; /* used for sysfs support */
void *tunable; /* address of the tunable to adjust */
void *checked; /* address of the variable that is controlled by */
/* the tunable. This is the calling subsystem's */
@@ -141,6 +157,7 @@ static inline int is_tunable_registered(
.max = { \
.value = (_max), \
}, \
+ .tun_kobj = { .tun = NULL, }, \
.tunable = (_tun), \
.checked = (_chk), \
}
@@ -194,8 +211,12 @@ static inline int activate_auto_tuning(i
}


+extern void init_auto_tuning(void);
extern int register_tunable(struct auto_tune *);
extern int unregister_tunable(struct auto_tune *);
+extern int tunable_sysfs_setup(struct auto_tune *);
+extern ssize_t show_tuning_mode(struct auto_tune *, char *);
+extern ssize_t store_tuning_mode(struct auto_tune *, const char *, size_t);


#else /* CONFIG_AKT */
@@ -210,6 +231,8 @@ extern int unregister_tunable(struct aut
#define register_tunable(a) 0
#define unregister_tunable(a) 0

+static inline void init_auto_tuning(void) { }
+
#endif /* CONFIG_AKT */

extern void fork_late_init(void);
Index: linux-2.6.20-rc4/init/main.c
===================================================================
--- linux-2.6.20-rc4.orig/init/main.c 2007-01-29 13:36:41.000000000 +0100
+++ linux-2.6.20-rc4/init/main.c 2007-01-29 15:33:43.000000000 +0100
@@ -614,6 +614,7 @@ asmlinkage void __init start_kernel(void
signals_init();
/* rootfs populating might need page-writeback */
page_writeback_init();
+ init_auto_tuning();
fork_late_init();
#ifdef CONFIG_PROC_FS
proc_root_init();
Index: linux-2.6.20-rc4/kernel/autotune/Makefile
===================================================================
--- linux-2.6.20-rc4.orig/kernel/autotune/Makefile 2007-01-29 13:40:06.000000000 +0100
+++ linux-2.6.20-rc4/kernel/autotune/Makefile 2007-01-29 15:34:30.000000000 +0100
@@ -2,6 +2,6 @@
# Makefile for akt
#

-obj-y := akt.o
+obj-y := akt.o akt_sysfs.o


Index: linux-2.6.20-rc4/kernel/autotune/akt.c
===================================================================
--- linux-2.6.20-rc4.orig/kernel/autotune/akt.c 2007-01-29 14:03:16.000000000 +0100
+++ linux-2.6.20-rc4/kernel/autotune/akt.c 2007-01-29 15:42:55.000000000 +0100
@@ -26,6 +26,8 @@
* FUNCTIONS:
* register_tunable (exported)
* unregister_tunable (exported)
+ * show_tuning_mode (exported)
+ * store_tuning_mode (exported)
*/

#include <linux/init.h>
@@ -34,6 +36,9 @@
#include <linux/akt.h>


+#define AKT_AUTO 1
+#define AKT_MANUAL 0
+
/**
* register_tunable - Inserts a tunable structure into sysfs
* @tun: tunable structure to be registered
@@ -50,6 +55,8 @@
*/
int register_tunable(struct auto_tune *tun)
{
+ int rc = 0;
+
if (tun == NULL) {
printk(KERN_ERR
"AKT: Bad tunable structure pointer (NULL)\n");
@@ -80,7 +87,10 @@ int register_tunable(struct auto_tune *t
return -EINVAL;
}

- return 0;
+ if (!(rc = tunable_sysfs_setup(tun)))
+ tun->flags |= TUNABLE_REGISTERED;
+
+ return rc;
}

EXPORT_SYMBOL_GPL(register_tunable);
@@ -117,3 +127,82 @@ int unregister_tunable(struct auto_tune
}

EXPORT_SYMBOL_GPL(unregister_tunable);
+
+
+/**
+ * show_tuning_mode - Outputs the tuning mode of a given tunable
+ * @tun_addr: registered tunable structure to check
+ * @buf: output buffer
+ *
+ * This is the get operation called by tunable_attr_show (i.e. when the file
+ * /sys/tunables/<tunable>/autotune is displayed).
+ * Outputs "1" if the corresponding tunable is automatically adjustable,
+ * "0" else
+ *
+ * Returns: >0 - output string length (including the '\0')
+ * <0 - failure
+ */
+ssize_t show_tuning_mode(struct auto_tune *tun_addr, char *buf)
+{
+ int valid;
+
+ if (tun_addr == NULL) {
+ printk(KERN_ERR "AKT: tunable address is invalid\n");
+ return -EINVAL;
+ }
+
+ spin_lock(&tun_addr->tunable_lck);
+
+ valid = is_auto_tune_enabled(tun_addr);
+
+ spin_unlock(&tun_addr->tunable_lck);
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", valid);
+}
+
+
+/**
+ * store_tuning_mode - Sets the tuning mode of a given tunable
+ * @tun_addr: registered tunable structure to set
+ * @buf: input buffer
+ * @count: input buffer length (including the '\0')
+ *
+ * This is the set operation called by tunable_attr_store (i.e. when a string
+ * is stored into /sys/tunables/<tunable>/autotune).
+ * "1" makes the corresponding tunable automatically adjustable
+ * "0" makes the corresponding tunable manually adjustable
+ *
+ * Returns: >0 - number of characters used from the input buffer
+ * <0 - failure
+ */
+ssize_t store_tuning_mode(struct auto_tune *tun_addr, const char *buffer,
+ size_t count)
+{
+ int new_value;
+
+ if (sscanf(buffer, "%d", &new_value) != 1)
+ return -EINVAL;
+
+ if (new_value != AKT_AUTO && new_value != AKT_MANUAL)
+ return -EINVAL;
+
+ if (tun_addr == NULL) {
+ printk(KERN_ERR "AKT: NULL pointer passed in\n");
+ return -EINVAL;
+ }
+
+ spin_lock(&tun_addr->tunable_lck);
+
+ switch (new_value) {
+ case AKT_AUTO:
+ tun_addr->flags |= AUTO_TUNE_ENABLE;
+ break;
+ case AKT_MANUAL:
+ tun_addr->flags &= ~AUTO_TUNE_ENABLE;
+ break;
+ }
+
+ spin_unlock(&tun_addr->tunable_lck);
+
+ return strnlen(buffer, PAGE_SIZE);
+}
Index: linux-2.6.20-rc4/kernel/autotune/akt_sysfs.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.20-rc4/kernel/autotune/akt_sysfs.c 2007-01-29 15:39:05.000000000 +0100
@@ -0,0 +1,214 @@
+/*
+ * linux/kernel/autotune/akt_sysfs.c
+ *
+ * Automatic Kernel Tunables for Linux
+ * sysfs bindings for AKT
+ *
+ * Copyright (C) 2006 Bull S.A.S
+ *
+ * Author: Nadia Derbey <Nadia.Derbey@bull.net>
+ *
+ * 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
+ */
+
+/*
+ * FUNCTIONS:
+ * tunable_attr_show (static)
+ * tunable_attr_store (static)
+ * tunable_sysfs_setup
+ * add_tunable_attrs (static)
+ * init_auto_tuning
+ */
+
+
+#include <linux/init.h>
+#include <linux/stat.h>
+#include <linux/module.h>
+#include <linux/akt.h>
+
+
+
+
+struct tunable_attribute {
+ struct attribute attr;
+ ssize_t (*show)(struct auto_tune *, char *);
+ ssize_t (*store)(struct auto_tune *, const char *, size_t);
+};
+
+#define TUNABLE_ATTR(_name, _mode, _show, _store) \
+struct tunable_attribute tun_attr_##_name = __ATTR(_name, _mode, _show, _store)
+
+
+static TUNABLE_ATTR(autotune, S_IWUSR | S_IRUGO, show_tuning_mode,
+ store_tuning_mode);
+
+static struct tunable_attribute *tunable_sysfs_attrs[] = {
+ &tun_attr_autotune, /* to (de)activate auto tuning */
+ NULL,
+};
+
+
+
+#define to_tunable_kobj(obj) container_of(obj, struct tunable_kobject, kobj)
+#define to_tunable(obj) container_of(obj, struct auto_tune, tun_kobj)
+#define to_tunable_attr(_attr) \
+ container_of(_attr, struct tunable_attribute, attr)
+
+
+static int add_tunable_attrs(struct auto_tune *);
+
+
+/**
+ * tunable_attr_show - Show method for the tunables subsystem
+ * @kobj: tunable associated kobject
+ * @attr: tunable attribute to read. Can be one of:
+ * tun_attr_autotune
+ * @buf: output buffer
+ *
+ * Forwards any read call to the show method of the owning attribute
+ *
+ * Returns: >0 - output string length (including the '\0')
+ * <0 - failure
+ */
+static ssize_t tunable_attr_show(struct kobject *kobj,
+ struct attribute *attr,
+ char *buf)
+{
+ struct tunable_attribute *tun_attr = to_tunable_attr(attr);
+ struct tunable_kobject *tkobj = to_tunable_kobj(kobj);
+ struct auto_tune *tunable = to_tunable(tkobj);
+ ssize_t count = -EIO;
+
+ if (tun_attr->show)
+ count = tun_attr->show(tunable, buf);
+ return count;
+}
+
+
+/**
+ * tunable_attr_store - Store method for the tunables subsystem
+ * @kobj: tunable associated kobject
+ * @attr: tunable attribute to update. Can be one of:
+ * tun_attr_autotune
+ * @buf: input buffer
+ * @count: input buffer length (including the '\0')
+ *
+ * Forwards any write call to the store method of the owning attribute
+ *
+ * Returns: >0 - number of characters used from the input buffer
+ * <0 - failure
+ */
+static ssize_t tunable_attr_store(struct kobject *kobj,
+ struct attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ struct tunable_attribute *tun_attr = to_tunable_attr(attr);
+ struct tunable_kobject *tkobj = to_tunable_kobj(kobj);
+ struct auto_tune *tunable = to_tunable(tkobj);
+ ssize_t ret = -EIO;
+
+ if (tun_attr->store)
+ ret = tun_attr->store(tunable, buf, count);
+ return ret;
+}
+
+
+static struct sysfs_ops tunables_sysfs_ops = {
+ .show = tunable_attr_show,
+ .store = tunable_attr_store,
+};
+
+
+static struct kobj_type tunables_ktype = {
+ .sysfs_ops = &tunables_sysfs_ops,
+};
+
+
+decl_subsys(tunables, &tunables_ktype, NULL);
+
+
+/**
+ * tunable_sysfs_setup - Registers one tunable into sysfs
+ * @tunable: tunable structure to be registered
+ *
+ * Called by register_tunable()
+ * The tunable is a kobject with 1 attributes:
+ * autotune (rw): enables to (de)activate the auto tuning for the tunable
+ *
+ * Returns: 0 - successful
+ * <0 - failure
+ */
+
+#define tunable_kobj(t) t->tun_kobj.kobj
+
+int tunable_sysfs_setup(struct auto_tune *tunable)
+{
+ int err = 0;
+
+ memset(&(tunable_kobj(tunable)), 0, sizeof(tunable_kobj(tunable)));
+ if ((err = kobject_set_name(&(tunable_kobj(tunable)), "%s",
+ tunable->name)))
+ return err;
+
+ kobj_set_kset_s(&(tunable->tun_kobj), tunables_subsys);
+ tunable->tun_kobj.tun = tunable;
+
+ if ((err = kobject_register(&(tunable_kobj(tunable)))))
+ return err;
+
+ if ((err = add_tunable_attrs(tunable)))
+ kobject_unregister(&(tunable_kobj(tunable)));
+
+ return err;
+}
+
+
+/**
+ * add_tunable_attrs - Creates the attributes for a tunable
+ * @tunable: tunable structure being registered
+ *
+ * Called by tunable_sysfs_setup()
+ * Adds the set of predefined attributes for a tunable being registered
+ *
+ * Returns: 0 - successful
+ * <0 - failure
+ */
+static int add_tunable_attrs(struct auto_tune *tunable)
+{
+ struct tunable_attribute *attr;
+ int error = 0;
+ int i;
+
+ for (i = 0; (attr = tunable_sysfs_attrs[i]) && !error; i++) {
+ error = sysfs_create_file(&(tunable_kobj(tunable)),
+ &(attr->attr));
+ }
+
+ return error;
+}
+
+
+/**
+ * init_auto_tuning - registers the tunables subssystem in sysfs
+ */
+void __init init_auto_tuning(void)
+{
+ int error = subsystem_register(&tunables_subsys);
+
+ if (error)
+ printk(KERN_ERR
+ "AKT: Failed registering tunables subsystem\n");
+}

--
-
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