Memory Allocation on Linux

Linux 内存分配过程：
free -> buff/cache -> swap

~]# free -g
              total        used        free      shared  buff/cache   available
Mem:              7           1           5           0           0           5
Swap:             5           0           5

Top swap usage of processes.

for file in /proc/*/status; do awk '/VmSwap|Name|^Pid/{printf $2 " " $3}END{print ""}' $file; done | sort -k 3 -n -r | head

内存不足，无法满足程序需求时，会发生内存溢出，进而导致系统杀死当前占用最多内存的进程。
Out of memory: killed process