http://tonylixu.blogspot.com/2014/01/linux-kernel-tuning-swappiness-and.html
"When a process forks, or calls the fork() function, its entire page table is cloned. In other words, the child process has a complete copy of the parent’s memory space, which requires, as you’d expect, twice the amount of RAM."
这个不太对, linuxde fork很久以前就是copy-on-write.