/*
* Simple selection loop. We chose the process with the highest
* number of 'points'.
*
* (not docbooked, we don't want this one cluttering up the manual)
*/
static struct task_struct *select_bad_process(unsigned int *ppoints,
unsigned long totalpages, const nodemask_t *nodemask,
bool force_kill)
{
struct task_struct *g, *p;
struct task_struct *chosen = NULL;
unsigned long chosen_points = 0;
rcu_read_lock();
do_each_thread(g, p) {
unsigned int points;
switch (oom_scan_process_thread(p, totalpages, nodemask,
force_kill)) {
case OOM_SCAN_SELECT:
chosen = p;
chosen_points = ULONG_MAX;
/* fall through */
case OOM_SCAN_CONTINUE:
continue;
case OOM_SCAN_ABORT:
rcu_read_unlock();
return ERR_PTR(-1UL);
case OOM_SCAN_OK:
break;
};
points = oom_badness(p, NULL, nodemask, totalpages);
if (points > chosen_points) {
chosen = p;
chosen_points = points;
}
} while_each_thread(g, p);
/*
* Simple selection loop. We chose the process with the highest
* number of 'points'. Returns -1 on scan abort.
*/
static struct task_struct *select_bad_process(struct oom_control *oc,
unsigned int *ppoints, unsigned long totalpages)
{
struct task_struct *g, *p;
struct task_struct *chosen = NULL;
unsigned long chosen_points = 0;
rcu_read_lock();
for_each_process_thread(g, p) {
unsigned int points;
switch (oom_scan_process_thread(oc, p, totalpages)) {
case OOM_SCAN_SELECT:
chosen = p;
chosen_points = ULONG_MAX;
/* fall through */
case OOM_SCAN_CONTINUE:
continue;
case OOM_SCAN_ABORT:
rcu_read_unlock();
return (struct task_struct *)(-1UL);
case OOM_SCAN_OK:
break;
};
points = oom_badness(p, NULL, oc->nodemask, totalpages);
if (!points || points < chosen_points)
continue;
/* Prefer thread group leaders for display purposes */
if (points == chosen_points && thread_group_leader(chosen))
continue;
chosen = p;
chosen_points = points;
}
/*
* Simple selection loop. We chose the process with the highest
* number of 'points'. We expect the caller will lock the tasklist.
*
* (not docbooked, we don't want this one cluttering up the manual)
*/
static struct task_struct *select_bad_process(unsigned int *ppoints,
unsigned long totalpages, struct mem_cgroup *mem,
const nodemask_t *nodemask)
{
struct task_struct *g, *p;
struct task_struct *chosen = NULL;
*ppoints = 0;
do_each_thread(g, p) {
unsigned int points;
if (p->exit_state)
continue;
if (oom_unkillable_task(p, mem, nodemask))
continue;
/*
* This task already has access to memory reserves and is
* being killed. Don't allow any other task access to the
* memory reserve.
*
* Note: this may have a chance of deadlock if it gets
* blocked waiting for another task which itself is waiting
* for memory. Is there a better alternative?
*/
if (test_tsk_thread_flag(p, TIF_MEMDIE))
return ERR_PTR(-1UL);
if (!p->mm)
continue;
if (p->flags & PF_EXITING) {
/*
* If p is the current task and is in the process of
* releasing memory, we allow the "kill" to set
* TIF_MEMDIE, which will allow it to gain access to
* memory reserves. Otherwise, it may stall forever.
*
* The loop isn't broken here, however, in case other
* threads are found to have already been oom killed.
*/
if (p == current) {
chosen = p;
*ppoints = 1000;
} else {
/*
* If this task is not being ptraced on exit,
* then wait for it to finish before killing
* some other task unnecessarily.
*/
if (!(p->group_leader->ptrace & PT_TRACE_EXIT))
return ERR_PTR(-1UL);
}
}
points = oom_badness(p, mem, nodemask, totalpages);
if (points > *ppoints) {
chosen = p;
*ppoints = points;
}
} while_each_thread(g, p);
static int oom_evaluate_task(struct task_struct *task, void *arg)
{
struct oom_control *oc = arg;
unsigned long points;
if (oom_unkillable_task(task, NULL, oc->nodemask))
goto next;
/*
* This task already has access to memory reserves and is being killed.
* Don't allow any other task to have access to the reserves unless
* the task has MMF_OOM_SKIP because chances that it would release
* any memory is quite low.
*/
if (!is_sysrq_oom(oc) && tsk_is_oom_victim(task)) {
if (test_bit(MMF_OOM_SKIP, &task->signal->oom_mm->flags))
goto next;
goto abort;
}
/*
* If task is allocating a lot of memory and has been marked to be
* killed first if it triggers an oom, then select it.
*/
if (oom_task_origin(task)) {
points = ULONG_MAX;
goto select;
}
points = oom_badness(task, NULL, oc->nodemask, oc->totalpages);
if (!points || points < oc->chosen_points)
goto next;
/* Prefer thread group leaders for display purposes */
if (points == oc->chosen_points && thread_group_leader(oc->chosen))
goto next;
select:
if (oc->chosen)
put_task_struct(oc->chosen);
get_task_struct(task);
oc->chosen = task;
oc->chosen_points = points;
next:
return 0;
abort:
if (oc->chosen)
put_task_struct(oc->chosen);
oc->chosen = (void *)-1UL;
return 1;
}
/*
* Simple selection loop. We chose the process with the highest
* number of 'points'. Returns -1 on scan abort.
*/
static struct task_struct *select_bad_process(struct oom_control *oc,
unsigned int *ppoints, unsigned long totalpages)
{
struct task_struct *p;
struct task_struct *chosen = NULL;
unsigned long chosen_points = 0;
rcu_read_lock();
for_each_process(p) {
unsigned int points;
switch (oom_scan_process_thread(oc, p, totalpages)) {
case OOM_SCAN_SELECT:
chosen = p;
chosen_points = ULONG_MAX;
/* fall through */
case OOM_SCAN_CONTINUE:
continue;
case OOM_SCAN_ABORT:
rcu_read_unlock();
return (struct task_struct *)(-1UL);
case OOM_SCAN_OK:
break;
};
points = oom_badness(p, NULL, oc->nodemask, totalpages);
if (!points || points < chosen_points)
continue;
chosen = p;
chosen_points = points;
}
if (chosen)
get_task_struct(chosen);
rcu_read_unlock();
*ppoints = chosen_points * 1000 / totalpages;
return chosen;
}
