linux/kernel/sched/auto_group.c
Andi Kleen ed82b8a1ff sched/core: Move the sched_to_prio[] arrays out of line
When building a kernel with a gcc 6 snapshot the compiler complains
about unused const static variables for prio_to_weight and prio_to_mult
for multiple scheduler files (all but core.c and autogroup.c)

The way the array is currently declared it will be duplicated in
every scheduler file that includes sched.h, which seems rather wasteful.

Move the array out of line into core.c. I also added a sched_ prefix
to avoid any potential name space collisions.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1448859583-3252-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-12-04 10:34:46 +01:00

250 lines
5.5 KiB
C

#include "sched.h"
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/kallsyms.h>
#include <linux/utsname.h>
#include <linux/security.h>
#include <linux/export.h>
unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1;
static struct autogroup autogroup_default;
static atomic_t autogroup_seq_nr;
void __init autogroup_init(struct task_struct *init_task)
{
autogroup_default.tg = &root_task_group;
kref_init(&autogroup_default.kref);
init_rwsem(&autogroup_default.lock);
init_task->signal->autogroup = &autogroup_default;
}
void autogroup_free(struct task_group *tg)
{
kfree(tg->autogroup);
}
static inline void autogroup_destroy(struct kref *kref)
{
struct autogroup *ag = container_of(kref, struct autogroup, kref);
#ifdef CONFIG_RT_GROUP_SCHED
/* We've redirected RT tasks to the root task group... */
ag->tg->rt_se = NULL;
ag->tg->rt_rq = NULL;
#endif
sched_offline_group(ag->tg);
sched_destroy_group(ag->tg);
}
static inline void autogroup_kref_put(struct autogroup *ag)
{
kref_put(&ag->kref, autogroup_destroy);
}
static inline struct autogroup *autogroup_kref_get(struct autogroup *ag)
{
kref_get(&ag->kref);
return ag;
}
static inline struct autogroup *autogroup_task_get(struct task_struct *p)
{
struct autogroup *ag;
unsigned long flags;
if (!lock_task_sighand(p, &flags))
return autogroup_kref_get(&autogroup_default);
ag = autogroup_kref_get(p->signal->autogroup);
unlock_task_sighand(p, &flags);
return ag;
}
static inline struct autogroup *autogroup_create(void)
{
struct autogroup *ag = kzalloc(sizeof(*ag), GFP_KERNEL);
struct task_group *tg;
if (!ag)
goto out_fail;
tg = sched_create_group(&root_task_group);
if (IS_ERR(tg))
goto out_free;
kref_init(&ag->kref);
init_rwsem(&ag->lock);
ag->id = atomic_inc_return(&autogroup_seq_nr);
ag->tg = tg;
#ifdef CONFIG_RT_GROUP_SCHED
/*
* Autogroup RT tasks are redirected to the root task group
* so we don't have to move tasks around upon policy change,
* or flail around trying to allocate bandwidth on the fly.
* A bandwidth exception in __sched_setscheduler() allows
* the policy change to proceed.
*/
free_rt_sched_group(tg);
tg->rt_se = root_task_group.rt_se;
tg->rt_rq = root_task_group.rt_rq;
#endif
tg->autogroup = ag;
sched_online_group(tg, &root_task_group);
return ag;
out_free:
kfree(ag);
out_fail:
if (printk_ratelimit()) {
printk(KERN_WARNING "autogroup_create: %s failure.\n",
ag ? "sched_create_group()" : "kmalloc()");
}
return autogroup_kref_get(&autogroup_default);
}
bool task_wants_autogroup(struct task_struct *p, struct task_group *tg)
{
if (tg != &root_task_group)
return false;
/*
* We can only assume the task group can't go away on us if
* autogroup_move_group() can see us on ->thread_group list.
*/
if (p->flags & PF_EXITING)
return false;
return true;
}
static void
autogroup_move_group(struct task_struct *p, struct autogroup *ag)
{
struct autogroup *prev;
struct task_struct *t;
unsigned long flags;
BUG_ON(!lock_task_sighand(p, &flags));
prev = p->signal->autogroup;
if (prev == ag) {
unlock_task_sighand(p, &flags);
return;
}
p->signal->autogroup = autogroup_kref_get(ag);
if (!READ_ONCE(sysctl_sched_autogroup_enabled))
goto out;
for_each_thread(p, t)
sched_move_task(t);
out:
unlock_task_sighand(p, &flags);
autogroup_kref_put(prev);
}
/* Allocates GFP_KERNEL, cannot be called under any spinlock */
void sched_autogroup_create_attach(struct task_struct *p)
{
struct autogroup *ag = autogroup_create();
autogroup_move_group(p, ag);
/* drop extra reference added by autogroup_create() */
autogroup_kref_put(ag);
}
EXPORT_SYMBOL(sched_autogroup_create_attach);
/* Cannot be called under siglock. Currently has no users */
void sched_autogroup_detach(struct task_struct *p)
{
autogroup_move_group(p, &autogroup_default);
}
EXPORT_SYMBOL(sched_autogroup_detach);
void sched_autogroup_fork(struct signal_struct *sig)
{
sig->autogroup = autogroup_task_get(current);
}
void sched_autogroup_exit(struct signal_struct *sig)
{
autogroup_kref_put(sig->autogroup);
}
static int __init setup_autogroup(char *str)
{
sysctl_sched_autogroup_enabled = 0;
return 1;
}
__setup("noautogroup", setup_autogroup);
#ifdef CONFIG_PROC_FS
int proc_sched_autogroup_set_nice(struct task_struct *p, int nice)
{
static unsigned long next = INITIAL_JIFFIES;
struct autogroup *ag;
int err;
if (nice < MIN_NICE || nice > MAX_NICE)
return -EINVAL;
err = security_task_setnice(current, nice);
if (err)
return err;
if (nice < 0 && !can_nice(current, nice))
return -EPERM;
/* this is a heavy operation taking global locks.. */
if (!capable(CAP_SYS_ADMIN) && time_before(jiffies, next))
return -EAGAIN;
next = HZ / 10 + jiffies;
ag = autogroup_task_get(p);
down_write(&ag->lock);
err = sched_group_set_shares(ag->tg, sched_prio_to_weight[nice + 20]);
if (!err)
ag->nice = nice;
up_write(&ag->lock);
autogroup_kref_put(ag);
return err;
}
void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
{
struct autogroup *ag = autogroup_task_get(p);
if (!task_group_is_autogroup(ag->tg))
goto out;
down_read(&ag->lock);
seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice);
up_read(&ag->lock);
out:
autogroup_kref_put(ag);
}
#endif /* CONFIG_PROC_FS */
#ifdef CONFIG_SCHED_DEBUG
int autogroup_path(struct task_group *tg, char *buf, int buflen)
{
if (!task_group_is_autogroup(tg))
return 0;
return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id);
}
#endif /* CONFIG_SCHED_DEBUG */