Srivatsa Vaddagiri wrote:
> Enable user-id based fair group scheduling. This is usefull for anyone
> who wants to test the group scheduler w/o having to enable
> CONFIG_CGROUPS.
> 
> A separate scheduling group (i.e struct task_grp) is automatically created 
> for 
> every new user added to the system. Upon uid change for a task, it is made to 
> move to the corresponding scheduling group.
> 
> A /proc tunable (/proc/root_user_share) is also provided to tune root
> user's quota of cpu bandwidth.
> 
> Signed-off-by : Srivatsa Vaddagiri <[EMAIL PROTECTED]>
> Signed-off-by : Dhaval Giani <[EMAIL PROTECTED]>
> 
> 
> ---
>  include/linux/sched.h |    4 +++
>  init/Kconfig          |   13 ++++++++++++
>  kernel/sched.c        |    9 ++++++++
>  kernel/sched_debug.c  |   52 
> ++++++++++++++++++++++++++++++++++++++++++++++++++
>  kernel/user.c         |   43 +++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 121 insertions(+)
> 
> Index: linux-2.6.23-rc6/include/linux/sched.h
> ===================================================================
> --- linux-2.6.23-rc6.orig/include/linux/sched.h
> +++ linux-2.6.23-rc6/include/linux/sched.h
> @@ -596,6 +596,10 @@ struct user_struct {
>       /* Hash table maintenance information */
>       struct hlist_node uidhash_node;
>       uid_t uid;
> +
> +#ifdef CONFIG_FAIR_USER_SCHED
> +     struct task_grp *tg;
> +#endif
>  };
>  
>  extern struct user_struct *find_user(uid_t);
> Index: linux-2.6.23-rc6/init/Kconfig
> ===================================================================
> --- linux-2.6.23-rc6.orig/init/Kconfig
> +++ linux-2.6.23-rc6/init/Kconfig
> @@ -289,6 +289,19 @@ config FAIR_GROUP_SCHED
>         This feature lets cpu scheduler recognize task groups and control cpu
>         bandwidth allocation to such task groups.
>  
> +choice
> +     depends on FAIR_GROUP_SCHED
> +     prompt "Basis for grouping tasks"
> +     default FAIR_USER_SCHED
> +
> +     config FAIR_USER_SCHED
> +             bool "user id"
> +             help
> +               This option will choose userid as the basis for grouping
> +               tasks, thus providing equal cpu bandwidth to each user.
> +
> +endchoice
> +
>  config SYSFS_DEPRECATED
>       bool "Create deprecated sysfs files"
>       default y
> Index: linux-2.6.23-rc6/kernel/sched.c
> ===================================================================
> --- linux-2.6.23-rc6.orig/kernel/sched.c
> +++ linux-2.6.23-rc6/kernel/sched.c
> @@ -199,7 +199,12 @@ struct task_grp init_task_grp =  {
>                               .cfs_rq = init_cfs_rq_p,
>                                };
>  
> +#ifdef CONFIG_FAIR_USER_SCHED
> +#define INIT_TASK_GRP_LOAD   2*NICE_0_LOAD
> +#else
>  #define INIT_TASK_GRP_LOAD   NICE_0_LOAD
> +#endif
> +
>  static int init_task_grp_load = INIT_TASK_GRP_LOAD;
>  
>  /* return group to which a task belongs */
> @@ -207,7 +212,11 @@ static inline struct task_grp *task_grp(
>  {
>       struct task_grp *tg;
>  
> +#ifdef CONFIG_FAIR_USER_SCHED
> +     tg = p->user->tg;
> +#else
>       tg  = &init_task_grp;
> +#endif
>  
>       return tg;
>  }
> Index: linux-2.6.23-rc6/kernel/sched_debug.c
> ===================================================================
> --- linux-2.6.23-rc6.orig/kernel/sched_debug.c
> +++ linux-2.6.23-rc6/kernel/sched_debug.c
> @@ -214,6 +214,49 @@ static void sysrq_sched_debug_show(void)
>       sched_debug_show(NULL, NULL);
>  }
>  
> +#ifdef CONFIG_FAIR_USER_SCHED
> +
> +static DEFINE_MUTEX(root_user_share_mutex);
> +
> +static int
> +root_user_share_read_proc(char *page, char **start, off_t off, int count,
> +                              int *eof, void *data)
> +{
> +     int len;
> +
> +     len = sprintf(page, "%d\n", init_task_grp_load);
> +
> +     return len;
> +}

or use this oneliner:

        return sprintf(page, "%d\n", init_task_grp_load);

> +
> +static int
> +root_user_share_write_proc(struct file *file, const char __user *buffer,
> +                              unsigned long count, void *data)
> +{
> +     unsigned long shares;
> +     char kbuf[sizeof(unsigned long)+1];
> +     int rc = 0;
> +
> +     if (copy_from_user(kbuf, buffer, sizeof(kbuf)))
> +             return -EFAULT;
> +
> +     shares = simple_strtoul(kbuf, NULL, 0);
> +
> +     if (!shares)
> +             shares = NICE_0_LOAD;
> +
> +     mutex_lock(&root_user_share_mutex);
> +
> +     init_task_grp_load = shares;
> +     rc = sched_group_set_shares(&init_task_grp, shares);
> +
> +     mutex_unlock(&root_user_share_mutex);
> +
> +     return (rc < 0 ? rc : count);
> +}
> +
> +#endif       /* CONFIG_FAIR_USER_SCHED */
> +
>  static int sched_debug_open(struct inode *inode, struct file *filp)
>  {
>       return single_open(filp, sched_debug_show, NULL);
> @@ -236,6 +279,15 @@ static int __init init_sched_debug_procf
>  
>       pe->proc_fops = &sched_debug_fops;
>  
> +#ifdef CONFIG_FAIR_USER_SCHED
> +     pe = create_proc_entry("root_user_share", 0644, NULL);
> +     if (!pe)
> +             return -ENOMEM;
> +
> +     pe->read_proc = root_user_share_read_proc;
> +     pe->write_proc = root_user_share_write_proc;
> +#endif
> +
>       return 0;
>  }
>  
> Index: linux-2.6.23-rc6/kernel/user.c
> ===================================================================
> --- linux-2.6.23-rc6.orig/kernel/user.c
> +++ linux-2.6.23-rc6/kernel/user.c
> @@ -50,8 +50,41 @@ struct user_struct root_user = {
>       .uid_keyring    = &root_user_keyring,
>       .session_keyring = &root_session_keyring,
>  #endif
> +#ifdef CONFIG_FAIR_USER_SCHED
> +     .tg             = &init_task_grp,
> +#endif
>  };
>  
> +#ifdef CONFIG_FAIR_USER_SCHED
> +static void sched_destroy_user(struct user_struct *up)
> +{
> +     sched_destroy_group(up->tg);
> +}
> +
> +static int sched_create_user(struct user_struct *up)
> +{
> +     int rc = 0;
> +
> +     up->tg = sched_create_group();
> +     if (IS_ERR(up->tg))
> +             rc = -ENOMEM;
> +
> +     return rc;
> +}
> +
> +static void sched_switch_user(struct task_struct *p)
> +{
> +     sched_move_task(p);
> +}
> +
> +#else        /* CONFIG_FAIR_USER_SCHED */
> +
> +static void sched_destroy_user(struct user_struct *up) { }
> +static int sched_create_user(struct user_struct *up) { return 0; }
> +static void sched_switch_user(struct task_struct *p) { }
> +
> +#endif       /* CONFIG_FAIR_USER_SCHED */
> +
>  /*
>   * These routines must be called with the uidhash spinlock held!
>   */
> @@ -109,6 +142,7 @@ 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_destroy_user(up);
>               key_put(up->uid_keyring);
>               key_put(up->session_keyring);
>               kmem_cache_free(uid_cachep, up);
> @@ -150,6 +184,13 @@ struct user_struct * alloc_uid(struct us
>                       return NULL;
>               }
>  
> +             if (sched_create_user(new) < 0) {
> +                     key_put(new->uid_keyring);
> +                     key_put(new->session_keyring);
> +                     kmem_cache_free(uid_cachep, new);
> +                     return NULL;
> +             }
> +
>               /*
>                * Before adding this, check whether we raced
>                * on adding the same user already..
> @@ -157,6 +198,7 @@ struct user_struct * alloc_uid(struct us
>               spin_lock_irq(&uidhash_lock);
>               up = uid_hash_find(uid, hashent);
>               if (up) {
> +                     sched_destroy_user(new);
>                       key_put(new->uid_keyring);
>                       key_put(new->session_keyring);
>                       kmem_cache_free(uid_cachep, new);
> @@ -184,6 +226,7 @@ void switch_uid(struct user_struct *new_
>       atomic_dec(&old_user->processes);
>       switch_uid_keyring(new_user);
>       current->user = new_user;
> +     sched_switch_user(current);
>  
>       /*
>        * We need to synchronize with __sigqueue_alloc()
> 

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