This patch tracks number of users in a system and divides cpu bandwidth
equally among them.
Signed-off-by : Srivatsa Vaddagiri <[EMAIL PROTECTED]>
---
diff -puN include/linux/sched.h~user-interface include/linux/sched.h
--- linux-2.6.20-rc5/include/linux/sched.h~user-interface 2007-01-25
20:44:53.000000000 +0530
+++ linux-2.6.20-rc5-vatsa/include/linux/sched.h 2007-01-25
20:44:53.000000000 +0530
@@ -533,7 +533,18 @@ struct signal_struct {
#ifdef CONFIG_FAIRSCHED
struct cpu_usage;
-#endif
+
+int sched_alloc_user(struct user_struct *user);
+void sched_free_user(struct user_struct *user);
+void sched_move_task(void);
+
+#else
+
+static inline int sched_alloc_user(struct user_struct *user) { return 0; }
+static inline void sched_free_user(struct user_struct *user) { }
+static inline void sched_move_task(void) { }
+
+#endif /* CONFIG_FAIRSCHED */
/*
* Some day this will be a full-fledged user tracking system..
@@ -562,6 +573,7 @@ struct user_struct {
#ifdef CONFIG_FAIRSCHED
int cpu_limit;
struct cpu_usage *cpu_usage;
+ struct list_head fair_sched_list;
#endif
};
diff -puN kernel/user.c~user-interface kernel/user.c
--- linux-2.6.20-rc5/kernel/user.c~user-interface 2007-01-25
20:44:53.000000000 +0530
+++ linux-2.6.20-rc5-vatsa/kernel/user.c 2007-01-25 20:44:53.000000000
+0530
@@ -51,6 +51,10 @@ struct user_struct root_user = {
.uid_keyring = &root_user_keyring,
.session_keyring = &root_session_keyring,
#endif
+#ifdef CONFIG_FAIRSCHED
+ .cpu_limit = 0, /* No limit */
+ .fair_sched_list = LIST_HEAD_INIT(root_user.fair_sched_list),
+#endif
};
/*
@@ -112,6 +116,7 @@ void free_uid(struct user_struct *up)
if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
uid_hash_remove(up);
spin_unlock_irqrestore(&uidhash_lock, flags);
+ sched_free_user(up);
key_put(up->uid_keyring);
key_put(up->session_keyring);
kmem_cache_free(uid_cachep, up);
@@ -153,6 +158,8 @@ struct user_struct * alloc_uid(uid_t uid
return NULL;
}
+ sched_alloc_user(new);
+
/*
* Before adding this, check whether we raced
* on adding the same user already..
@@ -163,6 +170,7 @@ struct user_struct * alloc_uid(uid_t uid
key_put(new->uid_keyring);
key_put(new->session_keyring);
kmem_cache_free(uid_cachep, new);
+ sched_free_user(new);
} else {
uid_hash_insert(new, hashent);
up = new;
@@ -186,6 +194,7 @@ void switch_uid(struct user_struct *new_
atomic_inc(&new_user->processes);
atomic_dec(&old_user->processes);
switch_uid_keyring(new_user);
+ sched_move_task();
current->user = new_user;
/*
diff -puN kernel/sched.c~user-interface kernel/sched.c
--- linux-2.6.20-rc5/kernel/sched.c~user-interface 2007-01-25
20:44:53.000000000 +0530
+++ linux-2.6.20-rc5-vatsa/kernel/sched.c 2007-01-26 09:04:04.000000000
+0530
@@ -7221,3 +7221,63 @@ void set_curr_task(int cpu, struct task_
}
#endif
+
+#ifdef CONFIG_FAIRSCHED
+
+static struct list_head user_list = LIST_HEAD_INIT(user_list);
+static atomic_t non_root_users;
+
+static void recalc_user_limits(void)
+{
+ int nr_users;
+ struct user_struct *user;
+
+ nr_users = atomic_read(&non_root_users);
+ if (!nr_users)
+ return;
+
+ list_for_each_entry(user, &user_list, fair_sched_list)
+ user->cpu_limit = 100/nr_users;
+}
+
+/* Allocate cpu_usage structure for the new task-group */
+int sched_alloc_user(struct user_struct *user)
+{
+ int i;
+
+ user->cpu_usage = alloc_percpu(struct cpu_usage);
+ if (!user->cpu_usage)
+ return -ENOMEM;
+
+ for_each_possible_cpu(i) {
+ struct cpu_usage *cu;
+
+ cu = per_cpu_ptr(user->cpu_usage, i);
+ cu->tokens = 1;
+ cu->last_update = 0;
+ cu->starve_count = 0;
+ }
+
+ list_add(&user->fair_sched_list, &user_list);
+ atomic_inc(&non_root_users);
+
+ recalc_user_limits();
+
+ return 0;
+}
+
+/* Deallocate cpu_usage structure */
+void sched_free_user(struct user_struct *user)
+{
+ list_del(&user->fair_sched_list);
+ atomic_dec(&non_root_users);
+ recalc_user_limits();
+ free_percpu(user->cpu_usage);
+}
+
+void sched_move_task(void)
+{
+ clear_tsk_starving(current);
+}
+
+#endif
diff -puN init/Kconfig~user-interface init/Kconfig
--- linux-2.6.20-rc5/init/Kconfig~user-interface 2007-01-25
20:44:53.000000000 +0530
+++ linux-2.6.20-rc5-vatsa/init/Kconfig 2007-01-25 20:44:54.000000000 +0530
@@ -249,6 +249,13 @@ config CPUSETS
Say N if unsure.
+config FAIRSCHED
+ bool "Fair user CPU scheduler"
+ depends on EXPERIMENTAL
+ help
+ This options lets you allocate equal cpu bandwidth to each
+ non-root user.
+
config SYSFS_DEPRECATED
bool "Create deprecated sysfs files"
default y
_
--
Regards,
vatsa
-
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