diff options
author | Ingo Molnar <mingo@elte.hu> | 2006-01-14 13:20:41 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-14 18:25:20 -0800 |
commit | b0a9499c3dd50d333e2aedb7e894873c58da3785 (patch) | |
tree | 1b9610020884091984ce8290c70bebdc3e7bb09b /kernel/sched.c | |
parent | 2d0cfb527944c2cfee2cffab14f52d483e329fcf (diff) | |
download | kernel_samsung_espresso10-b0a9499c3dd50d333e2aedb7e894873c58da3785.zip kernel_samsung_espresso10-b0a9499c3dd50d333e2aedb7e894873c58da3785.tar.gz kernel_samsung_espresso10-b0a9499c3dd50d333e2aedb7e894873c58da3785.tar.bz2 |
[PATCH] sched: add new SCHED_BATCH policy
Add a new SCHED_BATCH (3) scheduling policy: such tasks are presumed
CPU-intensive, and will acquire a constant +5 priority level penalty. Such
policy is nice for workloads that are non-interactive, but which do not
want to give up their nice levels. The policy is also useful for workloads
that want a deterministic scheduling policy without interactivity causing
extra preemptions (between that workload's tasks).
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r-- | kernel/sched.c | 48 |
1 files changed, 33 insertions, 15 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index c9dec2a..e1dc903 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -748,10 +748,14 @@ static int recalc_task_prio(task_t *p, unsigned long long now) unsigned long long __sleep_time = now - p->timestamp; unsigned long sleep_time; - if (__sleep_time > NS_MAX_SLEEP_AVG) - sleep_time = NS_MAX_SLEEP_AVG; - else - sleep_time = (unsigned long)__sleep_time; + if (unlikely(p->policy == SCHED_BATCH)) + sleep_time = 0; + else { + if (__sleep_time > NS_MAX_SLEEP_AVG) + sleep_time = NS_MAX_SLEEP_AVG; + else + sleep_time = (unsigned long)__sleep_time; + } if (likely(sleep_time > 0)) { /* @@ -3560,7 +3564,7 @@ void set_user_nice(task_t *p, long nice) * The RT priorities are set via sched_setscheduler(), but we still * allow the 'normal' nice value to be set - but as expected * it wont have any effect on scheduling until the task is - * not SCHED_NORMAL: + * not SCHED_NORMAL/SCHED_BATCH: */ if (rt_task(p)) { p->static_prio = NICE_TO_PRIO(nice); @@ -3706,10 +3710,16 @@ static void __setscheduler(struct task_struct *p, int policy, int prio) BUG_ON(p->array); p->policy = policy; p->rt_priority = prio; - if (policy != SCHED_NORMAL) + if (policy != SCHED_NORMAL && policy != SCHED_BATCH) { p->prio = MAX_RT_PRIO-1 - p->rt_priority; - else + } else { p->prio = p->static_prio; + /* + * SCHED_BATCH tasks are treated as perpetual CPU hogs: + */ + if (policy == SCHED_BATCH) + p->sleep_avg = 0; + } } /** @@ -3733,29 +3743,35 @@ recheck: if (policy < 0) policy = oldpolicy = p->policy; else if (policy != SCHED_FIFO && policy != SCHED_RR && - policy != SCHED_NORMAL) - return -EINVAL; + policy != SCHED_NORMAL && policy != SCHED_BATCH) + return -EINVAL; /* * Valid priorities for SCHED_FIFO and SCHED_RR are - * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL is 0. + * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL and + * SCHED_BATCH is 0. */ if (param->sched_priority < 0 || (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) return -EINVAL; - if ((policy == SCHED_NORMAL) != (param->sched_priority == 0)) + if ((policy == SCHED_NORMAL || policy == SCHED_BATCH) + != (param->sched_priority == 0)) return -EINVAL; /* * Allow unprivileged RT tasks to decrease priority: */ if (!capable(CAP_SYS_NICE)) { - /* can't change policy */ - if (policy != p->policy && - !p->signal->rlim[RLIMIT_RTPRIO].rlim_cur) + /* + * can't change policy, except between SCHED_NORMAL + * and SCHED_BATCH: + */ + if (((policy != SCHED_NORMAL && p->policy != SCHED_BATCH) && + (policy != SCHED_BATCH && p->policy != SCHED_NORMAL)) && + !p->signal->rlim[RLIMIT_RTPRIO].rlim_cur) return -EPERM; /* can't increase priority */ - if (policy != SCHED_NORMAL && + if ((policy != SCHED_NORMAL && policy != SCHED_BATCH) && param->sched_priority > p->rt_priority && param->sched_priority > p->signal->rlim[RLIMIT_RTPRIO].rlim_cur) @@ -4233,6 +4249,7 @@ asmlinkage long sys_sched_get_priority_max(int policy) ret = MAX_USER_RT_PRIO-1; break; case SCHED_NORMAL: + case SCHED_BATCH: ret = 0; break; } @@ -4256,6 +4273,7 @@ asmlinkage long sys_sched_get_priority_min(int policy) ret = 1; break; case SCHED_NORMAL: + case SCHED_BATCH: ret = 0; } return ret; |