virtual memory exhausted: Cannot allocate memory Linux虚拟内存不足，扩展虚拟内存的解决办法

Linux虚拟内存不足，扩展虚拟内存的解决办法

virtual memory exhausted: Cannot allocate memory

在编译软件的时候，出现了这个错误：

virtual memory exhausted: Cannot allocate memory

使用free -m命令检查swap分区情况

lk@Mibook:~$ free -m
              total        used        free      shared  buff/cache   available
Mem:           3828        1212         113        1022        2501        1315
Swap:           976         856         120

发现交换分区只有976M ，显然太小了，所以考虑增加虚拟内存。

1 创建用于交换分区的空间

标准格式：

$ dd if=/dev/zero of=/mnt/swap bs=1024 count=4096000 

运行后：

lk@Mibook:~$ sudo dd if=/dev/zero of=/mnt/swap bs=1024 count=4096000 
4096000+0 records in
4096000+0 records out
4194304000 bytes (4.2 GB, 3.9 GiB) copied, 19.1016 s, 220 MB/s

count=1024 代表设置1G大小swap分区，

我这里设置了4096，也就是4个G大小的swap分区。

2 设置交换分区文件

标准格式：

$ mkswap /mnt/swap

运行后：

lk@Mibook:~$ sudo mkswap /mnt/swap
Setting up swapspace version 1, size = 3.9 GiB (4194299904 bytes)
no label, UUID=3a46d2c9-2eba-433e-ba9a-6e98a5f256ba

3 立即启用交换分区文件

标准格式：

$ swapon /mnt/swap

运行后：

lk@Mibook:~$ sudo swapon /mnt/swap
swapon: /mnt/swap: insecure permissions 0644, 0600 suggested.

查看一下/etc/rc.local，如果有swapoff -a需要改为swapon -a

lk@Mibook:~$ cat /etc/rc.local
#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

exit 0

4 设置开机启用swap分区

查看/etc/fstab文件

lk@Mibook:~$ cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
#                
# / was on /dev/sda2 during installation
UUID=388726b7-1e49-429a-b9dd-7e285931159b /               ext4    errors=remount-ro 0       1
# /boot/efi was on /dev/sda1 during installation
UUID=5E17-7068  /boot/efi       vfat    umask=0077      0       1
# swap was on /dev/sda3 during installation
UUID=600bf7c2-11c2-4e94-9ee5-062cbe203afc none            swap    sw              0       0

使用sudo gedit /etc/fstab命令打开，在末尾添加/mnt/swap swap swap defaults 0 0

再次使用cat /etc/fstab命令查看确认

lk@Mibook:~$ cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
#                
# / was on /dev/sda2 during installation
UUID=388726b7-1e49-429a-b9dd-7e285931159b /               ext4    errors=remount-ro 0       1
# /boot/efi was on /dev/sda1 during installation
UUID=5E17-7068  /boot/efi       vfat    umask=0077      0       1
# swap was on /dev/sda3 during installation
UUID=600bf7c2-11c2-4e94-9ee5-062cbe203afc none            swap    sw              0       0
/mnt/swap swap swap defaults 0 0

5 查看新的分区情况

再次执行free -m查看效果

lk@Mibook:~$ free -m
              total        used        free      shared  buff/cache   available
Mem:           3828        1233         254         965        2340        1352
Swap:          4976         806        4169

发现swap分区变成了4个G，扩展成功。

参考文章阿里云ECS Linux开启swap（虚拟内存）