Commit a5be2d0d authored by Tejun Heo's avatar Tejun Heo

freezer: rename thaw_process() to __thaw_task() and simplify the implementation

thaw_process() now has only internal users - system and cgroup
freezers.  Remove the unnecessary return value, rename, unexport and
collapse __thaw_process() into it.  This will help further updates to
the freezer code.

-v3: oom_kill grew a use of thaw_process() while this patch was
     pending.  Convert it to use __thaw_task() for now.  In the longer
     term, this should be handled by allowing tasks to die if killed
     even if it's frozen.

-v2: minor style update as suggested by Matt.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Paul Menage <menage@google.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
parent 8a32c441
......@@ -45,7 +45,7 @@ static inline bool should_send_signal(struct task_struct *p)
}
/* Takes and releases task alloc lock using task_lock() */
extern int thaw_process(struct task_struct *p);
extern void __thaw_task(struct task_struct *t);
extern bool __refrigerator(bool check_kthr_stop);
extern int freeze_processes(void);
......@@ -178,7 +178,6 @@ static inline int frozen(struct task_struct *p) { return 0; }
static inline int freezing(struct task_struct *p) { return 0; }
static inline void set_freeze_flag(struct task_struct *p) {}
static inline void clear_freeze_flag(struct task_struct *p) {}
static inline int thaw_process(struct task_struct *p) { return 1; }
static inline bool __refrigerator(bool check_kthr_stop) { return false; }
static inline int freeze_processes(void) { return -ENOSYS; }
......
......@@ -130,7 +130,7 @@ struct cgroup_subsys freezer_subsys;
* write_lock css_set_lock (cgroup iterator start)
* task->alloc_lock
* read_lock css_set_lock (cgroup iterator start)
* task->alloc_lock (inside thaw_process(), prevents race with refrigerator())
* task->alloc_lock (inside __thaw_task(), prevents race with refrigerator())
* sighand->siglock
*/
static struct cgroup_subsys_state *freezer_create(struct cgroup_subsys *ss,
......@@ -300,9 +300,8 @@ static void unfreeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
struct task_struct *task;
cgroup_iter_start(cgroup, &it);
while ((task = cgroup_iter_next(cgroup, &it))) {
thaw_process(task);
}
while ((task = cgroup_iter_next(cgroup, &it)))
__thaw_task(task);
cgroup_iter_end(cgroup, &it);
freezer->state = CGROUP_THAWED;
......
......@@ -145,18 +145,8 @@ void cancel_freezing(struct task_struct *p)
}
}
static int __thaw_process(struct task_struct *p)
{
if (frozen(p)) {
p->flags &= ~PF_FROZEN;
return 1;
}
clear_freeze_flag(p);
return 0;
}
/*
* Wake up a frozen process
* Wake up a frozen task
*
* task_lock() is needed to prevent the race with refrigerator() which may
* occur if the freezing of tasks fails. Namely, without the lock, if the
......@@ -164,15 +154,18 @@ static int __thaw_process(struct task_struct *p)
* refrigerator() could call frozen_process(), in which case the task would be
* frozen and no one would thaw it.
*/
int thaw_process(struct task_struct *p)
void __thaw_task(struct task_struct *p)
{
bool was_frozen;
task_lock(p);
if (__thaw_process(p) == 1) {
task_unlock(p);
wake_up_process(p);
return 1;
}
was_frozen = frozen(p);
if (was_frozen)
p->flags &= ~PF_FROZEN;
else
clear_freeze_flag(p);
task_unlock(p);
return 0;
if (was_frozen)
wake_up_process(p);
}
EXPORT_SYMBOL(thaw_process);
......@@ -186,7 +186,7 @@ static void thaw_tasks(bool nosig_only)
if (cgroup_freezing_or_frozen(p))
continue;
thaw_process(p);
__thaw_task(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
}
......
......@@ -328,7 +328,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
*/
if (test_tsk_thread_flag(p, TIF_MEMDIE)) {
if (unlikely(frozen(p)))
thaw_process(p);
__thaw_task(p);
return ERR_PTR(-1UL);
}
if (!p->mm)
......
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