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authorSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>2007-10-15 17:00:09 +0200
committerIngo Molnar <mingo@elte.hu>2007-10-15 17:00:09 +0200
commit24e377a83220ef05c9b5bec7e01d65eed6609aa6 (patch)
tree9303b3d9f91ee39517d379aaac06c0432be8a9b8 /kernel
parent9b5b77512dce239fa168183fa71896712232e95a (diff)
sched: add fair-user scheduler
Enable user-id based fair group scheduling. This is useful 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 <vatsa@linux.vnet.ibm.com> Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched.c9
-rw-r--r--kernel/sched_debug.c52
-rw-r--r--kernel/user.c43
3 files changed, 104 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index e10c403b121..f33608e9e1a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -200,7 +200,12 @@ 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 */
@@ -208,7 +213,11 @@ static inline struct task_grp *task_grp(struct task_struct *p)
{
struct task_grp *tg;
+#ifdef CONFIG_FAIR_USER_SCHED
+ tg = p->user->tg;
+#else
tg = &init_task_grp;
+#endif
return tg;
}
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 3e47e870b04..57ee9d5630a 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -212,6 +212,49 @@ 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;
+}
+
+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);
@@ -234,6 +277,15 @@ static int __init init_sched_debug_procfs(void)
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;
}
diff --git a/kernel/user.c b/kernel/user.c
index 9ca2848fc35..c6387fac932 100644
--- a/kernel/user.c
+++ b/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 user_namespace *ns, uid_t uid)
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 user_namespace *ns, uid_t uid)
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_user)
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()