When this flag is 2, the kernel uses a "never overcommit" policy that attempts to prevent any overcommit of memory. Note that user_reserve_kbytes affects this policy. 设置的值为2表示不允许overcommit,这时候如果停掉swap,那么可用内存减少,用户空间的内存申请就可能触发overcommit被拒绝。但是事后查了一...