[PATCH 11/13] sched: Remove sched_setscheduler2()
From: Peter Zijlstra
Date: Tue Dec 17 2013 - 07:49:45 EST
Expand sched_{set,get}attr() to include the policy and nice value.
This obviates the need for sched_setscheduler2().
The new sched_setattr() call now covers the functionality of:
sched_setscheduler(),
sched_setparam(),
setpriority(.which = PRIO_PROCESS)
And sched_getattr() now covers:
sched_getscheduler(),
sched_getparam(),
getpriority(.which = PRIO_PROCESS)
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
arch/arm/include/asm/unistd.h | 2
arch/arm/include/uapi/asm/unistd.h | 5 -
arch/arm/kernel/calls.S | 3
arch/x86/syscalls/syscall_32.tbl | 1
arch/x86/syscalls/syscall_64.tbl | 1
include/linux/sched.h | 24 +++--
include/linux/syscalls.h | 2
kernel/sched/core.c | 173 +++++++++++++++++++------------------
kernel/sched/sched.h | 13 +-
9 files changed, 119 insertions(+), 105 deletions(-)
--- a/arch/arm/include/asm/unistd.h
+++ b/arch/arm/include/asm/unistd.h
@@ -15,7 +15,7 @@
#include <uapi/asm/unistd.h>
-#define __NR_syscalls (383)
+#define __NR_syscalls (382)
#define __ARM_NR_cmpxchg (__ARM_NR_BASE+0x00fff0)
#define __ARCH_WANT_STAT64
--- a/arch/arm/include/uapi/asm/unistd.h
+++ b/arch/arm/include/uapi/asm/unistd.h
@@ -406,9 +406,8 @@
#define __NR_process_vm_writev (__NR_SYSCALL_BASE+377)
#define __NR_kcmp (__NR_SYSCALL_BASE+378)
#define __NR_finit_module (__NR_SYSCALL_BASE+379)
-#define __NR_sched_setscheduler2 (__NR_SYSCALL_BASE+380)
-#define __NR_sched_setattr (__NR_SYSCALL_BASE+381)
-#define __NR_sched_getattr (__NR_SYSCALL_BASE+382)
+#define __NR_sched_setattr (__NR_SYSCALL_BASE+380)
+#define __NR_sched_getattr (__NR_SYSCALL_BASE+381)
/*
* This may need to be greater than __NR_last_syscall+1 in order to
--- a/arch/arm/kernel/calls.S
+++ b/arch/arm/kernel/calls.S
@@ -389,8 +389,7 @@
CALL(sys_process_vm_writev)
CALL(sys_kcmp)
CALL(sys_finit_module)
-/* 380 */ CALL(sys_sched_setscheduler2)
- CALL(sys_sched_setattr)
+/* 380 */ CALL(sys_sched_setattr)
CALL(sys_sched_getattr)
#ifndef syscalls_counted
.equ syscalls_padding, ((NR_syscalls + 3) & ~3) - NR_syscalls
--- a/arch/x86/syscalls/syscall_32.tbl
+++ b/arch/x86/syscalls/syscall_32.tbl
@@ -359,4 +359,3 @@
350 i386 finit_module sys_finit_module
351 i386 sched_setattr sys_sched_setattr
352 i386 sched_getattr sys_sched_getattr
-353 i386 sched_setscheduler2 sys_sched_setscheduler2
--- a/arch/x86/syscalls/syscall_64.tbl
+++ b/arch/x86/syscalls/syscall_64.tbl
@@ -322,7 +322,6 @@
313 common finit_module sys_finit_module
314 common sched_setattr sys_sched_setattr
315 common sched_getattr sys_sched_getattr
-316 common sched_setscheduler2 sys_sched_setscheduler2
#
# x32-specific system call numbers start at 512 to avoid cache impact
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -57,7 +57,7 @@ struct sched_param {
#include <asm/processor.h>
-#define SCHED_ATTR_SIZE_VER0 40 /* sizeof first published struct */
+#define SCHED_ATTR_SIZE_VER0 48 /* sizeof first published struct */
/*
* Extended scheduling parameters data structure.
@@ -85,7 +85,9 @@ struct sched_param {
*
* This is reflected by the actual fields of the sched_attr structure:
*
- * @sched_priority task's priority (might still be useful)
+ * @sched_policy task's scheduling policy
+ * @sched_nice task's nice value (SCHED_NORMAL/BATCH)
+ * @sched_priority task's static priority (SCHED_FIFO/RR)
* @sched_flags for customizing the scheduler behaviour
* @sched_deadline representative of the task's deadline
* @sched_runtime representative of the task's runtime
@@ -102,15 +104,21 @@ struct sched_param {
* available in the scheduling class file or in Documentation/.
*/
struct sched_attr {
- int sched_priority;
- unsigned int sched_flags;
+ u32 size;
+
+ u32 sched_policy;
+ u64 sched_flags;
+
+ /* SCHED_NORMAL, SCHED_BATCH */
+ s32 sched_nice;
+
+ /* SCHED_FIFO, SCHED_RR */
+ u32 sched_priority;
+
+ /* SCHED_DEADLINE */
u64 sched_runtime;
u64 sched_deadline;
u64 sched_period;
- u32 size;
-
- /* Align to u64. */
- u32 __reserved;
};
struct exec_domain;
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -278,8 +278,6 @@ asmlinkage long sys_clock_nanosleep(cloc
asmlinkage long sys_nice(int increment);
asmlinkage long sys_sched_setscheduler(pid_t pid, int policy,
struct sched_param __user *param);
-asmlinkage long sys_sched_setscheduler2(pid_t pid, int policy,
- struct sched_attr __user *attr);
asmlinkage long sys_sched_setparam(pid_t pid,
struct sched_param __user *param);
asmlinkage long sys_sched_setattr(pid_t pid,
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2973,6 +2973,7 @@ void rt_mutex_setprio(struct task_struct
__task_rq_unlock(rq);
}
#endif
+
void set_user_nice(struct task_struct *p, long nice)
{
int old_prio, delta, on_rq;
@@ -3147,24 +3148,6 @@ static struct task_struct *find_process_
return pid ? find_task_by_vpid(pid) : current;
}
-/* Actually do priority change: must hold rq lock. */
-static void
-__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
-{
- p->policy = policy;
- p->rt_priority = prio;
- p->normal_prio = normal_prio(p);
- /* we are holding p->pi_lock already */
- p->prio = rt_mutex_getprio(p);
- if (dl_prio(p->prio))
- p->sched_class = &dl_sched_class;
- else if (rt_prio(p->prio))
- p->sched_class = &rt_sched_class;
- else
- p->sched_class = &fair_sched_class;
- set_load_weight(p);
-}
-
/*
* This function initializes the sched_dl_entity of a newly becoming
* SCHED_DEADLINE task.
@@ -3188,6 +3171,34 @@ __setparam_dl(struct task_struct *p, con
dl_se->dl_new = 1;
}
+/* Actually do priority change: must hold pi & rq lock. */
+static void __setscheduler(struct rq *rq, struct task_struct *p,
+ const struct sched_attr *attr)
+{
+ int policy = attr->sched_policy;
+
+ p->policy = policy;
+
+ if (fair_policy(policy))
+ p->static_prio = NICE_TO_PRIO(attr->sched_nice);
+ if (rt_policy(policy))
+ p->rt_priority = attr->sched_priority;
+ if (dl_policy(policy))
+ __setparam_dl(p, attr);
+
+ p->normal_prio = normal_prio(p);
+ p->prio = rt_mutex_getprio(p);
+
+ if (dl_prio(p->prio))
+ p->sched_class = &dl_sched_class;
+ else if (rt_prio(p->prio))
+ p->sched_class = &rt_sched_class;
+ else
+ p->sched_class = &fair_sched_class;
+
+ set_load_weight(p);
+}
+
static void
__getparam_dl(struct task_struct *p, struct sched_attr *attr)
{
@@ -3234,11 +3245,12 @@ static bool check_same_owner(struct task
return match;
}
-static int __sched_setscheduler(struct task_struct *p, int policy,
+static int __sched_setscheduler(struct task_struct *p,
const struct sched_attr *attr,
bool user)
{
int retval, oldprio, oldpolicy = -1, on_rq, running;
+ int policy = attr->sched_policy;
unsigned long flags;
const struct sched_class *prev_class;
struct rq *rq;
@@ -3271,6 +3283,7 @@ static int __sched_setscheduler(struct t
(p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) ||
(!p->mm && attr->sched_priority > MAX_RT_PRIO-1))
return -EINVAL;
+
if ((dl_policy(policy) && !__checkparam_dl(attr)) ||
(rt_policy(policy) != (attr->sched_priority != 0)))
return -EINVAL;
@@ -3279,6 +3292,11 @@ static int __sched_setscheduler(struct t
* Allow unprivileged RT tasks to decrease priority:
*/
if (user && !capable(CAP_SYS_NICE)) {
+ if (fair_policy(policy)) {
+ if (!can_nice(p, attr->sched_nice))
+ return -EPERM;
+ }
+
if (rt_policy(policy)) {
unsigned long rlim_rtprio =
task_rlimit(p, RLIMIT_RTPRIO);
@@ -3337,12 +3355,18 @@ static int __sched_setscheduler(struct t
/*
* If not changing anything there's no need to proceed further:
*/
- if (unlikely(policy == p->policy && (!rt_policy(policy) ||
- attr->sched_priority == p->rt_priority) &&
- !dl_policy(policy))) {
+ if (unlikely(policy == p->policy)) {
+ if (fair_policy(policy) && attr->sched_nice != TASK_NICE(p))
+ goto change;
+ if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
+ goto change;
+ if (dl_policy(policy))
+ goto change;
+
task_rq_unlock(rq, p, &flags);
return 0;
}
+change:
if (user) {
#ifdef CONFIG_RT_GROUP_SCHED
@@ -3399,8 +3423,7 @@ static int __sched_setscheduler(struct t
*/
if ((dl_policy(policy) || dl_task(p)) &&
dl_overflow(p, policy, attr)) {
- __task_rq_unlock(rq);
- raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+ task_rq_unlock(rq, p, &flags);
return -EBUSY;
}
@@ -3415,9 +3438,7 @@ static int __sched_setscheduler(struct t
oldprio = p->prio;
prev_class = p->sched_class;
- if (dl_policy(policy))
- __setparam_dl(p, attr);
- __setscheduler(rq, p, policy, attr->sched_priority);
+ __setscheduler(rq, p, attr);
if (running)
p->sched_class->set_curr_task(rq);
@@ -3446,18 +3467,18 @@ int sched_setscheduler(struct task_struc
const struct sched_param *param)
{
struct sched_attr attr = {
+ .sched_policy = policy,
.sched_priority = param->sched_priority
};
- return __sched_setscheduler(p, policy, &attr, true);
+ return __sched_setscheduler(p, &attr, true);
}
EXPORT_SYMBOL_GPL(sched_setscheduler);
-int sched_setscheduler2(struct task_struct *p, int policy,
- const struct sched_attr *attr)
+int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
{
- return __sched_setscheduler(p, policy, attr, true);
+ return __sched_setscheduler(p, attr, true);
}
-EXPORT_SYMBOL_GPL(sched_setscheduler2);
+EXPORT_SYMBOL_GPL(sched_setattr);
/**
* sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
@@ -3476,9 +3497,10 @@ int sched_setscheduler_nocheck(struct ta
const struct sched_param *param)
{
struct sched_attr attr = {
+ .sched_policy = policy,
.sched_priority = param->sched_priority
};
- return __sched_setscheduler(p, policy, &attr, false);
+ return __sched_setscheduler(p, &attr, false);
}
static int
@@ -3561,6 +3583,12 @@ static int sched_copy_attr(struct sched_
if (ret)
return -EFAULT;
+ /*
+ * XXX: do we want to be lenient like existing syscalls; or do we want
+ * to be strict and return an error on out-of-bounds values?
+ */
+ attr->sched_nice = clamp(attr->sched_nice, -20, 19);
+
out:
return ret;
@@ -3570,33 +3598,6 @@ static int sched_copy_attr(struct sched_
goto out;
}
-static int
-do_sched_setscheduler2(pid_t pid, int policy,
- struct sched_attr __user *attr_uptr)
-{
- struct sched_attr attr;
- struct task_struct *p;
- int retval;
-
- if (!attr_uptr || pid < 0)
- return -EINVAL;
-
- if (sched_copy_attr(attr_uptr, &attr))
- return -EFAULT;
-
- rcu_read_lock();
- retval = -ESRCH;
- p = find_process_by_pid(pid);
- if (p != NULL) {
- if (dl_policy(policy))
- attr.sched_priority = 0;
- retval = sched_setscheduler2(p, policy, &attr);
- }
- rcu_read_unlock();
-
- return retval;
-}
-
/**
* sys_sched_setscheduler - set/change the scheduler policy and RT priority
* @pid: the pid in question.
@@ -3616,21 +3617,6 @@ SYSCALL_DEFINE3(sched_setscheduler, pid_
}
/**
- * sys_sched_setscheduler2 - same as above, but with extended sched_param
- * @pid: the pid in question.
- * @policy: new policy (could use extended sched_param).
- * @attr: structure containg the extended parameters.
- */
-SYSCALL_DEFINE3(sched_setscheduler2, pid_t, pid, int, policy,
- struct sched_attr __user *, attr)
-{
- if (policy < 0)
- return -EINVAL;
-
- return do_sched_setscheduler2(pid, policy, attr);
-}
-
-/**
* sys_sched_setparam - set/change the RT priority of a thread
* @pid: the pid in question.
* @param: structure containing the new RT priority.
@@ -3647,10 +3633,26 @@ SYSCALL_DEFINE2(sched_setparam, pid_t, p
* @pid: the pid in question.
* @attr: structure containing the extended parameters.
*/
-SYSCALL_DEFINE2(sched_setattr, pid_t, pid,
- struct sched_attr __user *, attr)
+SYSCALL_DEFINE2(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr)
{
- return do_sched_setscheduler2(pid, -1, attr);
+ struct sched_attr attr;
+ struct task_struct *p;
+ int retval;
+
+ if (!uattr || pid < 0)
+ return -EINVAL;
+
+ if (sched_copy_attr(uattr, &attr))
+ return -EFAULT;
+
+ rcu_read_lock();
+ retval = -ESRCH;
+ p = find_process_by_pid(pid);
+ if (p != NULL)
+ retval = sched_setattr(p, &attr);
+ rcu_read_unlock();
+
+ return retval;
}
/**
@@ -3797,8 +3799,14 @@ SYSCALL_DEFINE3(sched_getattr, pid_t, pi
if (retval)
goto out_unlock;
- __getparam_dl(p, &attr);
- attr.sched_priority = p->rt_priority;
+ attr.sched_policy = p->policy;
+ if (task_has_dl_policy(p))
+ __getparam_dl(p, &attr);
+ else if (task_has_rt_policy(p))
+ attr.sched_priority = p->rt_priority;
+ else
+ attr.sched_nice = TASK_NICE(p);
+
rcu_read_unlock();
retval = sched_read_attr(uattr, &attr, size);
@@ -6948,13 +6956,16 @@ EXPORT_SYMBOL(__might_sleep);
static void normalize_task(struct rq *rq, struct task_struct *p)
{
const struct sched_class *prev_class = p->sched_class;
+ struct sched_attr attr = {
+ .sched_policy = SCHED_NORMAL,
+ };
int old_prio = p->prio;
int on_rq;
on_rq = p->on_rq;
if (on_rq)
dequeue_task(rq, p, 0);
- __setscheduler(rq, p, SCHED_NORMAL, 0);
+ __setscheduler(rq, p, &attr);
if (on_rq) {
enqueue_task(rq, p, 0);
resched_task(rq->curr);
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -90,18 +90,19 @@ extern void update_cpu_load_active(struc
*/
#define DL_SCALE (10)
+static inline int fair_policy(int policy)
+{
+ return policy == SCHED_NORMAL || policy == SCHED_BATCH;
+}
+
static inline int rt_policy(int policy)
{
- if (policy == SCHED_FIFO || policy == SCHED_RR)
- return 1;
- return 0;
+ return policy == SCHED_FIFO || policy == SCHED_RR;
}
static inline int dl_policy(int policy)
{
- if (unlikely(policy == SCHED_DEADLINE))
- return 1;
- return 0;
+ return unlikely(policy == SCHED_DEADLINE);
}
static inline int task_has_rt_policy(struct task_struct *p)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/