Revert "sched/autogroup: Fix crash on reboot when autogroup is disabled"
This reverts commit 5258f386ea4e8454bc801fb443e8a4217da1947c,
because the underlying autogroups bug got fixed upstream in
a better way, via:
fd8ef11730f1 Revert "sched, autogroup: Stop going ahead if autogroup is disabled"
Cc: Mike Galbraith <efault@gmx.de>
Cc: Yong Zhang <yong.zhang0@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/kernel/sched/auto_group.c b/kernel/sched/auto_group.c
index 0f1bacb..0984a21 100644
--- a/kernel/sched/auto_group.c
+++ b/kernel/sched/auto_group.c
@@ -110,9 +110,6 @@
bool task_wants_autogroup(struct task_struct *p, struct task_group *tg)
{
- if (!sysctl_sched_autogroup_enabled)
- return false;
-
if (tg != &root_task_group)
return false;
@@ -146,11 +143,15 @@
p->signal->autogroup = autogroup_kref_get(ag);
+ if (!ACCESS_ONCE(sysctl_sched_autogroup_enabled))
+ goto out;
+
t = p;
do {
sched_move_task(t);
} while_each_thread(p, t);
+out:
unlock_task_sighand(p, &flags);
autogroup_kref_put(prev);
}
@@ -158,11 +159,8 @@
/* Allocates GFP_KERNEL, cannot be called under any spinlock */
void sched_autogroup_create_attach(struct task_struct *p)
{
- struct autogroup *ag;
+ struct autogroup *ag = autogroup_create();
- if (!sysctl_sched_autogroup_enabled)
- return;
- ag = autogroup_create();
autogroup_move_group(p, ag);
/* drop extra reference added by autogroup_create() */
autogroup_kref_put(ag);
@@ -178,15 +176,11 @@
void sched_autogroup_fork(struct signal_struct *sig)
{
- if (!sysctl_sched_autogroup_enabled)
- return;
sig->autogroup = autogroup_task_get(current);
}
void sched_autogroup_exit(struct signal_struct *sig)
{
- if (!sysctl_sched_autogroup_enabled)
- return;
autogroup_kref_put(sig->autogroup);
}
@@ -199,6 +193,58 @@
__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 < -20 || nice > 19)
+ 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, 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)
{
diff --git a/kernel/sched/auto_group.h b/kernel/sched/auto_group.h
index 4552c6b..8bd0471 100644
--- a/kernel/sched/auto_group.h
+++ b/kernel/sched/auto_group.h
@@ -4,6 +4,11 @@
#include <linux/rwsem.h>
struct autogroup {
+ /*
+ * reference doesn't mean how many thread attach to this
+ * autogroup now. It just stands for the number of task
+ * could use this autogroup.
+ */
struct kref kref;
struct task_group *tg;
struct rw_semaphore lock;
@@ -24,7 +29,9 @@
static inline struct task_group *
autogroup_task_group(struct task_struct *p, struct task_group *tg)
{
- if (task_wants_autogroup(p, tg))
+ int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled);
+
+ if (enabled && task_wants_autogroup(p, tg))
return p->signal->autogroup->tg;
return tg;
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b0fa5ad..26f65ea 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -367,8 +367,10 @@
.procname = "sched_autogroup_enabled",
.data = &sysctl_sched_autogroup_enabled,
.maxlen = sizeof(unsigned int),
- .mode = 0444,
- .proc_handler = proc_dointvec,
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
},
#endif
#ifdef CONFIG_CFS_BANDWIDTH