From 5cb350baf580017da38199625b7365b1763d7180 Mon Sep 17 00:00:00 2001 From: Dhaval Giani Date: Mon, 15 Oct 2007 17:00:14 +0200 Subject: sched: group scheduling, sysfs tunables Add tunables in sysfs to modify a user's cpu share. A directory is created in sysfs for each new user in the system. /sys/kernel/uids//cpu_share Reading this file returns the cpu shares granted for the user. Writing into this file modifies the cpu share for the user. Only an administrator is allowed to modify a user's cpu share. Ex: # cd /sys/kernel/uids/ # cat 512/cpu_share 1024 # echo 2048 > 512/cpu_share # cat 512/cpu_share 2048 # Signed-off-by: Srivatsa Vaddagiri Signed-off-by: Dhaval Giani Signed-off-by: Ingo Molnar --- kernel/sched.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index a3c3ec8..9ac9989 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -162,6 +162,8 @@ struct task_group { /* runqueue "owned" by this group on each cpu */ struct cfs_rq **cfs_rq; unsigned long shares; + /* spinlock to serialize modification to shares */ + spinlock_t lock; }; /* Default task group's sched entity on each cpu */ @@ -6533,6 +6535,7 @@ void __init sched_init(void) se->parent = NULL; } init_task_group.shares = init_task_group_load; + spin_lock_init(&init_task_group.lock); #endif for (j = 0; j < CPU_LOAD_IDX_MAX; j++) @@ -6777,6 +6780,7 @@ struct task_group *sched_create_group(void) } tg->shares = NICE_0_LOAD; + spin_lock_init(&tg->lock); return tg; @@ -6897,8 +6901,9 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares) { int i; + spin_lock(&tg->lock); if (tg->shares == shares) - return 0; + goto done; /* return -EINVAL if the new value is not sane */ @@ -6906,7 +6911,14 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares) for_each_possible_cpu(i) set_se_shares(tg->se[i], shares); +done: + spin_unlock(&tg->lock); return 0; } +unsigned long sched_group_shares(struct task_group *tg) +{ + return tg->shares; +} + #endif /* CONFIG_FAIR_GROUP_SCHED */ -- cgit v1.1