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| author | Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> | 2007-10-15 17:00:09 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2007-10-15 17:00:09 +0200 |
| commit | 24e377a83220ef05c9b5bec7e01d65eed6609aa6 (patch) | |
| tree | 9303b3d9f91ee39517d379aaac06c0432be8a9b8 /kernel/user.c | |
| parent | 9b5b77512dce239fa168183fa71896712232e95a (diff) | |
| download | lwn-24e377a83220ef05c9b5bec7e01d65eed6609aa6.tar.gz lwn-24e377a83220ef05c9b5bec7e01d65eed6609aa6.zip | |
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/user.c')
| -rw-r--r-- | kernel/user.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/kernel/user.c b/kernel/user.c index 9ca2848fc356..c6387fac932d 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() |