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Subject[RFC] [PATCH 02/12] Class creation/deletion
02/12 - ckrm_core_class_support

Provides functions to alloc and free a user defined class.
Provides utility macro to walk through the class hierarchy
--

Signed-Off-By: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-Off-By: Hubertus Franke <frankeh@us.ibm.com>
Signed-Off-By: Shailabh Nagar <nagar@watson.ibm.com>
Signed-Off-By: Gerrit Huizenga <gh@us.ibm.com>
Signed-Off-By: Vivek Kashyap <kashyapv@us.ibm.com>
Signed-Off-By: Matt Helsley <matthltc@us.ibm.com>

include/linux/ckrm.h | 8 ++
include/linux/ckrm_rc.h | 9 ++
kernel/ckrm/ckrm.c | 171 ++++++++++++++++++++++++++++++++++++++++++++----
3 files changed, 175 insertions(+), 13 deletions(-)
Index: linux2617-rc2/include/linux/ckrm.h
===================================================================
--- linux2617-rc2.orig/include/linux/ckrm.h
+++ linux2617-rc2/include/linux/ckrm.h
@@ -61,6 +61,8 @@ struct ckrm_shares {
* registered a resource controller (see include/linux/ckrm_rc.h).
*/
struct ckrm_class {
+ const char *name;
+ struct kref ref;
int depth; /* depth of this class. root == 0 */
spinlock_t class_lock; /* protects task_list, shares and children
* When grabbing class_lock in a hierarchy,
@@ -70,6 +72,12 @@ struct ckrm_class {
* grabbing resource specific lock */
struct ckrm_shares *shares[CKRM_MAX_RES_CTLRS];/* resource shares */
struct list_head class_list; /* entry in list of all classes */
+
+ struct list_head task_list; /* this class's tasks */
+
+ struct ckrm_class *parent;
+ struct list_head siblings; /* entry in list of siblings */
+ struct list_head children; /* head of children */
};

#endif /* CONFIG_CKRM */
Index: linux2617-rc2/kernel/ckrm/ckrm.c
===================================================================
--- linux2617-rc2.orig/kernel/ckrm/ckrm.c
+++ linux2617-rc2/kernel/ckrm/ckrm.c
@@ -19,14 +19,32 @@
*/

#include <linux/module.h>
-#include <linux/ckrm_rc.h>
+#include "ckrm_local.h"

static struct ckrm_controller *ckrm_controllers[CKRM_MAX_RES_CTLRS];
/* res_ctlrs_lock protects ckrm_controllers array and count in controllers*/
static spinlock_t res_ctlrs_lock = SPIN_LOCK_UNLOCKED;

static LIST_HEAD(ckrm_classes);/* link all classes */
-static rwlock_t ckrm_class_lock = RW_LOCK_UNLOCKED; /* protects ckrm_classes */
+static int ckrm_num_classes; /* Number of user defined classes */
+static rwlock_t ckrm_class_lock = RW_LOCK_UNLOCKED;
+ /* protects ckrm_classes list and ckrm_num_classes */
+
+struct ckrm_class ckrm_default_class = {
+ .task_list = LIST_HEAD_INIT(ckrm_default_class.task_list),
+ .class_lock = SPIN_LOCK_UNLOCKED,
+ .name = "task",
+ .class_list = LIST_HEAD_INIT(ckrm_default_class.class_list),
+ .siblings = LIST_HEAD_INIT(ckrm_default_class.siblings),
+ .children = LIST_HEAD_INIT(ckrm_default_class.children),
+};
+
+/* Must be called with parent's class_lock held */
+static inline void ckrm_remove_child(struct ckrm_class *child)
+{
+ list_del(&child->siblings);
+ child->parent = CKRM_NO_CLASS;
+}

/* Must be called with res_ctlr_lock held */
static inline int is_ctlr_id_valid(unsigned int ctlr_id)
@@ -97,6 +115,55 @@ static void do_alloc_shares_struct(struc
ckrm_get_controller(ctlr);
}

+static void ckrm_class_init(struct ckrm_class *class)
+{
+ class->class_lock = SPIN_LOCK_UNLOCKED;
+ kref_init(&class->ref);
+ INIT_LIST_HEAD(&class->task_list);
+ INIT_LIST_HEAD(&class->children);
+ INIT_LIST_HEAD(&class->siblings);
+}
+
+struct ckrm_class *ckrm_alloc_class(struct ckrm_class *parent,
+ const char *name)
+{
+ int i;
+ struct ckrm_class *class;
+
+ BUG_ON(parent == NULL);
+
+ kref_get(&parent->ref);
+ class = kzalloc(sizeof(struct ckrm_class), GFP_KERNEL);
+ if (!class) {
+ kref_put(&parent->ref, ckrm_release_class);
+ return NULL;
+ }
+ ckrm_class_init(class);
+ class->name = name;
+ class->depth = parent->depth + 1;
+
+ /* Add to parent */
+ spin_lock(&parent->class_lock);
+ class->parent = parent;
+ list_add(&class->siblings, &parent->children);
+ spin_unlock(&parent->class_lock);
+
+ write_lock(&ckrm_class_lock);
+ list_add_tail(&class->class_list, &ckrm_classes);
+ ckrm_num_classes++;
+ write_unlock(&ckrm_class_lock);
+
+ for (i = 0; i < CKRM_MAX_RES_CTLRS; i++) {
+ struct ckrm_controller *ctlr = ckrm_get_controller_by_id(i);
+ if (!ctlr)
+ continue;
+ do_alloc_shares_struct(class, ctlr);
+ ckrm_put_controller(ctlr);
+ }
+
+ return class;
+}
+
/* Free up the given resource specific information in a class */
static void do_free_shares_struct(struct ckrm_class *class,
struct ckrm_controller *ctlr)
@@ -114,6 +181,59 @@ static void do_free_shares_struct(struct
ckrm_put_controller(ctlr); /* Drop reference acquired in do_alloc */
}

+/*
+ * Release a class
+ * requires that all tasks were previously reassigned to another class
+ *
+ * Returns 0 on success -errno on failure.
+ */
+void ckrm_release_class(struct kref *kref)
+{
+ int i;
+ struct ckrm_class *class = container_of(kref,
+ struct ckrm_class, ref);
+ struct ckrm_class *parent = class->parent;
+
+ BUG_ON(ckrm_is_class_root(class));
+
+ for (i = 0; i < CKRM_MAX_RES_CTLRS; i++) {
+ struct ckrm_controller *ctlr = ckrm_get_controller_by_id(i);
+ if (!ctlr)
+ continue;
+ do_free_shares_struct(class, ctlr);
+ ckrm_put_controller(ctlr);
+ }
+
+ /* Remove this class from the list of all classes */
+ write_lock(&ckrm_class_lock);
+ list_del(&class->class_list);
+ ckrm_num_classes--;
+ write_unlock(&ckrm_class_lock);
+
+ /* remove from parent */
+ spin_lock(&parent->class_lock);
+ list_del(&class->siblings);
+ class->parent = CKRM_NO_CLASS;
+ spin_unlock(&parent->class_lock);
+
+ kref_put(&parent->ref, ckrm_release_class);
+ kfree(class);
+}
+
+int ckrm_free_class(struct ckrm_class *class)
+{
+ BUG_ON(ckrm_is_class_root(class));
+ spin_lock(&class->class_lock);
+ if (!list_empty(&class->children)) {
+ spin_unlock(&class->class_lock);
+ return -EBUSY;
+ }
+ spin_unlock(&class->class_lock);
+ kref_put(&class->ref, ckrm_release_class);
+ return 0;
+}
+
+
static int add_controller(struct ckrm_controller *ctlr)
{
int ctlr_id, ret = -ENOSPC;
@@ -128,7 +248,6 @@ static int add_controller(struct ckrm_co
spin_unlock(&res_ctlrs_lock);
return ret;
}
-
/*
* Interface for registering a resource controller.
*
@@ -138,7 +257,7 @@ static int add_controller(struct ckrm_co
int ckrm_register_controller(struct ckrm_controller *ctlr)
{
int ret;
- struct ckrm_class *class;
+ struct ckrm_class *class, *prev_class;

if (!ctlr)
return -EINVAL;
@@ -160,10 +279,20 @@ int ckrm_register_controller(struct ckrm
* Run through all classes and create the controller specific data
* structures.
*/
- read_lock(&ckrm_class_lock);
- list_for_each_entry(class, &ckrm_classes, class_list)
- do_alloc_shares_struct(class, ctlr);
- read_unlock(&ckrm_class_lock);
+ prev_class = NULL;
+ read_lock(&ckrm_class_lock);
+ list_for_each_entry(class, &ckrm_classes, class_list) {
+ kref_get(&class->ref);
+ read_unlock(&ckrm_class_lock);
+ do_alloc_shares_struct(class, ctlr);
+ if (prev_class)
+ kref_put(&prev_class->ref, ckrm_release_class);
+ prev_class = class;
+ read_lock(&ckrm_class_lock);
+ }
+ read_unlock(&ckrm_class_lock);
+ if (prev_class)
+ kref_put(&prev_class->ref, ckrm_release_class);
return 0;
}

@@ -188,7 +317,7 @@ static int remove_controller(struct ckrm
*/
int ckrm_unregister_controller(struct ckrm_controller *ctlr)
{
- struct ckrm_class *class;
+ struct ckrm_class *class, *prev_class;

if (!ctlr)
return -EINVAL;
@@ -197,10 +326,20 @@ int ckrm_unregister_controller(struct ck
return -EINVAL;

/* free shares structs for this resource from all the classes */
- read_lock(&ckrm_class_lock);
- list_for_each_entry_reverse(class, &ckrm_classes, class_list)
- do_free_shares_struct(class, ctlr);
- read_unlock(&ckrm_class_lock);
+ prev_class = NULL;
+ read_lock(&ckrm_class_lock);
+ list_for_each_entry_reverse(class, &ckrm_classes, class_list) {
+ kref_get(&class->ref);
+ read_unlock(&ckrm_class_lock);
+ do_free_shares_struct(class, ctlr);
+ if (prev_class)
+ kref_put(&prev_class->ref, ckrm_release_class);
+ prev_class = class;
+ read_lock(&ckrm_class_lock);
+ }
+ read_unlock(&ckrm_class_lock);
+ if (prev_class)
+ kref_put(&prev_class->ref, ckrm_release_class);

ckrm_put_controller(ctlr);
return remove_controller(ctlr);
@@ -208,3 +347,9 @@ int ckrm_unregister_controller(struct ck

EXPORT_SYMBOL_GPL(ckrm_register_controller);
EXPORT_SYMBOL_GPL(ckrm_unregister_controller);
+EXPORT_SYMBOL_GPL(ckrm_alloc_class);
+EXPORT_SYMBOL_GPL(ckrm_free_class);
+EXPORT_SYMBOL_GPL(ckrm_default_class);
+EXPORT_SYMBOL_GPL(ckrm_get_controller_by_name);
+EXPORT_SYMBOL_GPL(ckrm_get_controller_by_id);
+EXPORT_SYMBOL_GPL(ckrm_put_controller);
Index: linux2617-rc2/include/linux/ckrm_rc.h
===================================================================
--- linux2617-rc2.orig/include/linux/ckrm_rc.h
+++ linux2617-rc2/include/linux/ckrm_rc.h
@@ -64,4 +64,13 @@ struct ckrm_controller {

extern int ckrm_register_controller(struct ckrm_controller *);
extern int ckrm_unregister_controller(struct ckrm_controller *);
+extern struct ckrm_class ckrm_default_class;
+static inline int ckrm_is_class_root(const struct ckrm_class* class)
+{
+ return (class == &ckrm_default_class);
+}
+
+#define for_each_child(child, parent) \
+ list_for_each_entry(child, &parent->children, siblings)
+
#endif /* _LINUX_CKRM_RC_H */
--

----------------------------------------------------------------------
Chandra Seetharaman | Be careful what you choose....
- sekharan@us.ibm.com | .......you may get it.
----------------------------------------------------------------------
-
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