char buffer[PROC_NUMBUF];
int oom_adj = OOM_ADJUST_MIN;
size_t len;
- unsigned long flags;
if (!task)
return -ESRCH;
- if (lock_task_sighand(task, &flags)) {
- if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
- oom_adj = OOM_ADJUST_MAX;
- else
- oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
- OOM_SCORE_ADJ_MAX;
- unlock_task_sighand(task, &flags);
- }
+ if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
+ oom_adj = OOM_ADJUST_MAX;
+ else
+ oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
+ OOM_SCORE_ADJ_MAX;
put_task_struct(task);
len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
return simple_read_from_buffer(buf, count, ppos, buffer, len);
}
+static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
+{
+ static DEFINE_MUTEX(oom_adj_mutex);
+ struct mm_struct *mm = NULL;
+ struct task_struct *task;
+ int err = 0;
+
+ task = get_proc_task(file_inode(file));
+ if (!task)
+ return -ESRCH;
+
+ mutex_lock(&oom_adj_mutex);
+ if (legacy) {
+ if (oom_adj < task->signal->oom_score_adj &&
+ !capable(CAP_SYS_RESOURCE)) {
+ err = -EACCES;
+ goto err_unlock;
+ }
+ /*
+ * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
+ * /proc/pid/oom_score_adj instead.
+ */
+ pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
+ current->comm, task_pid_nr(current), task_pid_nr(task),
+ task_pid_nr(task));
+ } else {
+ if ((short)oom_adj < task->signal->oom_score_adj_min &&
+ !capable(CAP_SYS_RESOURCE)) {
+ err = -EACCES;
+ goto err_unlock;
+ }
+ }
+
+ /*
+ * Make sure we will check other processes sharing the mm if this is
+ * not vfrok which wants its own oom_score_adj.
+ * pin the mm so it doesn't go away and get reused after task_unlock
+ */
+ if (!task->vfork_done) {
+ struct task_struct *p = find_lock_task_mm(task);
+
+ if (p) {
+ if (atomic_read(&p->mm->mm_users) > 1) {
+ mm = p->mm;
+ atomic_inc(&mm->mm_count);
+ }
+ task_unlock(p);
+ }
+ }
+
+ task->signal->oom_score_adj = oom_adj;
+ if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
+ task->signal->oom_score_adj_min = (short)oom_adj;
+ trace_oom_score_adj_update(task);
+
+ if (mm) {
+ struct task_struct *p;
+
+ rcu_read_lock();
+ for_each_process(p) {
+ if (same_thread_group(task, p))
+ continue;
+
+ /* do not touch kernel threads or the global init */
+ if (p->flags & PF_KTHREAD || is_global_init(p))
+ continue;
+
+ task_lock(p);
+ if (!p->vfork_done && process_shares_mm(p, mm)) {
+ pr_info("updating oom_score_adj for %d (%s) from %d to %d because it shares mm with %d (%s). Report if this is unexpected.\n",
+ task_pid_nr(p), p->comm,
+ p->signal->oom_score_adj, oom_adj,
+ task_pid_nr(task), task->comm);
+ p->signal->oom_score_adj = oom_adj;
+ if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
+ p->signal->oom_score_adj_min = (short)oom_adj;
+ }
+ task_unlock(p);
+ }
+ rcu_read_unlock();
+ mmdrop(mm);
+ }
+err_unlock:
+ mutex_unlock(&oom_adj_mutex);
+ put_task_struct(task);
+ return err;
+}
+
/*
* /proc/pid/oom_adj exists solely for backwards compatibility with previous
* kernels. The effective policy is defined by oom_score_adj, which has a
static ssize_t oom_adj_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
- struct task_struct *task;
char buffer[PROC_NUMBUF];
int oom_adj;
- unsigned long flags;
int err;
memset(buffer, 0, sizeof(buffer));
goto out;
}
- task = get_proc_task(file_inode(file));
- if (!task) {
- err = -ESRCH;
- goto out;
- }
-
- task_lock(task);
- if (!task->mm) {
- err = -EINVAL;
- goto err_task_lock;
- }
-
- if (!lock_task_sighand(task, &flags)) {
- err = -ESRCH;
- goto err_task_lock;
- }
-
/*
* Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
* value is always attainable.
else
oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
- if (oom_adj < task->signal->oom_score_adj &&
- !capable(CAP_SYS_RESOURCE)) {
- err = -EACCES;
- goto err_sighand;
- }
-
- /*
- * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
- * /proc/pid/oom_score_adj instead.
- */
- pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
- current->comm, task_pid_nr(current), task_pid_nr(task),
- task_pid_nr(task));
-
- task->signal->oom_score_adj = oom_adj;
- trace_oom_score_adj_update(task);
-err_sighand:
- unlock_task_sighand(task, &flags);
-err_task_lock:
- task_unlock(task);
- put_task_struct(task);
+ err = __set_oom_adj(file, oom_adj, true);
out:
return err < 0 ? err : count;
}
struct task_struct *task = get_proc_task(file_inode(file));
char buffer[PROC_NUMBUF];
short oom_score_adj = OOM_SCORE_ADJ_MIN;
- unsigned long flags;
size_t len;
if (!task)
return -ESRCH;
- if (lock_task_sighand(task, &flags)) {
- oom_score_adj = task->signal->oom_score_adj;
- unlock_task_sighand(task, &flags);
- }
+ oom_score_adj = task->signal->oom_score_adj;
put_task_struct(task);
len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
return simple_read_from_buffer(buf, count, ppos, buffer, len);
static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
- struct task_struct *task;
char buffer[PROC_NUMBUF];
- unsigned long flags;
int oom_score_adj;
int err;
goto out;
}
- task = get_proc_task(file_inode(file));
- if (!task) {
- err = -ESRCH;
- goto out;
- }
-
- task_lock(task);
- if (!task->mm) {
- err = -EINVAL;
- goto err_task_lock;
- }
-
- if (!lock_task_sighand(task, &flags)) {
- err = -ESRCH;
- goto err_task_lock;
- }
-
- if ((short)oom_score_adj < task->signal->oom_score_adj_min &&
- !capable(CAP_SYS_RESOURCE)) {
- err = -EACCES;
- goto err_sighand;
- }
-
- task->signal->oom_score_adj = (short)oom_score_adj;
- if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
- task->signal->oom_score_adj_min = (short)oom_score_adj;
- trace_oom_score_adj_update(task);
-
-err_sighand:
- unlock_task_sighand(task, &flags);
-err_task_lock:
- task_unlock(task);
- put_task_struct(task);
+ err = __set_oom_adj(file, oom_score_adj, false);
out:
return err < 0 ? err : count;
}
projects / deliverable / linux.git / blobdiff