From 7479f3c9cf67edf5e8a76b21ea3726757f35cf53 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 15 Jan 2014 17:05:04 +0100 Subject: [PATCH] sched: Move SCHED_RESET_ON_FORK into attr::sched_flags I noticed the new sched_{set,get}attr() calls didn't properly deal with the SCHED_RESET_ON_FORK hack. Instead of propagating the flags in high bits nonsense use the brand spanking new attr::sched_flags field. Signed-off-by: Peter Zijlstra Cc: Juri Lelli Cc: Dario Faggioli Link: http://lkml.kernel.org/r/20140115162242.GJ31570@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- include/uapi/linux/sched.h | 5 +++++ kernel/sched/core.c | 42 +++++++++++++++++++++++++------------- 2 files changed, 33 insertions(+), 14 deletions(-) diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h index 2d5e49a2a6d2..34f9d7387d13 100644 --- a/include/uapi/linux/sched.h +++ b/include/uapi/linux/sched.h @@ -40,8 +40,13 @@ /* SCHED_ISO: reserved but not implemented yet */ #define SCHED_IDLE 5 #define SCHED_DEADLINE 6 + /* Can be ORed in to make sure the process is reverted back to SCHED_NORMAL on fork */ #define SCHED_RESET_ON_FORK 0x40000000 +/* + * For the sched_{set,get}attr() calls + */ +#define SCHED_FLAG_RESET_ON_FORK 0x01 #endif /* _UAPI_LINUX_SCHED_H */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5a6ccdf4b39d..93a2836b6220 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3267,8 +3267,7 @@ recheck: reset_on_fork = p->sched_reset_on_fork; policy = oldpolicy = p->policy; } else { - reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); - policy &= ~SCHED_RESET_ON_FORK; + reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK); if (policy != SCHED_DEADLINE && policy != SCHED_FIFO && policy != SCHED_RR && @@ -3277,6 +3276,9 @@ recheck: return -EINVAL; } + if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK)) + return -EINVAL; + /* * Valid priorities for SCHED_FIFO and SCHED_RR are * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, @@ -3443,6 +3445,26 @@ change: return 0; } +static int _sched_setscheduler(struct task_struct *p, int policy, + const struct sched_param *param, bool check) +{ + struct sched_attr attr = { + .sched_policy = policy, + .sched_priority = param->sched_priority, + .sched_nice = PRIO_TO_NICE(p->static_prio), + }; + + /* + * Fixup the legacy SCHED_RESET_ON_FORK hack + */ + if (policy & SCHED_RESET_ON_FORK) { + attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; + policy &= ~SCHED_RESET_ON_FORK; + attr.sched_policy = policy; + } + + return __sched_setscheduler(p, &attr, check); +} /** * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. * @p: the task in question. @@ -3456,12 +3478,7 @@ change: int sched_setscheduler(struct task_struct *p, int policy, const struct sched_param *param) { - struct sched_attr attr = { - .sched_policy = policy, - .sched_priority = param->sched_priority, - .sched_nice = PRIO_TO_NICE(p->static_prio), - }; - return __sched_setscheduler(p, &attr, true); + return _sched_setscheduler(p, policy, param, true); } EXPORT_SYMBOL_GPL(sched_setscheduler); @@ -3487,12 +3504,7 @@ EXPORT_SYMBOL_GPL(sched_setattr); int sched_setscheduler_nocheck(struct task_struct *p, int policy, const struct sched_param *param) { - struct sched_attr attr = { - .sched_policy = policy, - .sched_priority = param->sched_priority, - .sched_nice = PRIO_TO_NICE(p->static_prio), - }; - return __sched_setscheduler(p, &attr, false); + return _sched_setscheduler(p, policy, param, false); } static int @@ -3792,6 +3804,8 @@ SYSCALL_DEFINE3(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, goto out_unlock; attr.sched_policy = p->policy; + if (p->sched_reset_on_fork) + attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; if (task_has_dl_policy(p)) __getparam_dl(p, &attr); else if (task_has_rt_policy(p)) -- 2.20.1