Use -999 as OOM adj

[pizhenwei]

The atop deployment usually follows the rules:

• atop MUST NOT exceed the cgroup resource limitations
• atop has a higher priority on OOM

OOM_SCORE_ADJ_MIN(-1000) is a magic number which could not be killed by memory cgroup, this breaks the rules.

Detail of OOM_SCORE_ADJ_MIN, see linux/mm/oom_kill.c /*

• Kill provided task unless it's secured by setting
• oom_score_adj to OOM_SCORE_ADJ_MIN. / static int oom_kill_memcg_member(struct task_struct task, void *message) { if (task->signal->oom_score_adj != OOM_SCORE_ADJ_MIN && !is_global_init(task)) { get_task_struct(task); __oom_kill_process(task, message); } return 0; }

Use -999 instead of -1000 as atop default OOM adj.