X11 - X client数量达到上限并报错Maximum number of clients reachedxlsclients

Posted 2021-08-21 王万林 Ben

X11 - X client数量达到上限并报错Maximum number of clients reachedxlsclients

报错

thesre@HP-Z420-Workstation:~$ xlsclients
Maximum number of clients reachedxlsclients:  unable to open display ":0"

定位

看报错是X client数量达到上限了，我们来看下当前X server打开了多少X client。

thesre@HP-Z420-Workstation:~$ xlsclients
Maximum number of clients reachedxlsclients:  unable to open display ":0"

执行xlsclients无法查看，同上面一样提示达到上限的报错。我们关掉一个X client再查看下，

thesre@HP-Z420-Workstation:~$ xlsclients | head -5
HP-Z420-Workstation  gnome-shell
HP-Z420-Workstation  ibus-x11
HP-Z420-Workstation  ibus-extension-gtk3
HP-Z420-Workstation  gsd-keyboard
HP-Z420-Workstation  gsd-color
thesre@HP-Z420-Workstation:~$ xlsclients | wc -l
243

可以看到X client的数量达到了243个。而X server的上限默认值为256个，这个值已经接近上限了。（至于打开X Client数量到244后就不能继续打开了，未找到相关资料，也欢迎知道的读者帮忙补充一下，谢谢！）

解决

关闭一些不使用的X Client来释放一些，以便能打开新的X Client。

进一步了解

我们再看下这个数值是在哪里定义的。
man xorg
xorg的配置可从多处获取，其中配置文件是xorg.conf，接下来查看手册，
man 5 xorg.conf
如果需要配置MaxClient，则需要创建/etc/X11/xorg.conf文件，并在SERVERFLAGS SECTION下配置MacClients的配置。需要注意的是，该值必须是2的指数，可选的值有64，128，256和512。

实验

使用for循环试图一次性打开256个xclock：

thesre@HP-Z420-Workstation:~/Desktop$ for i in {1..256}; do echo $i; (xclock &); done
1
2
3
...snippet ommited...
239
240
241
Maximum number of clients reachedMaximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
242
Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Error: Can't open display: :0
Maximum number of clients reachedMaximum number of clients reachedError: Can't open display: :0
Error: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedMaximum number of clients reachedMaximum number of clients reachedError: Can't open display: :0
Error: Can't open display: :0
Error: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reached243
Error: Can't open display: :0
244
245
...snippet ommited...
255
256
thesre@HP-Z420-Workstation:~/Desktop$ Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedMaximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedMaximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Error: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedMaximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Error: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Maximum number of clients reachedError: Can't open display: :0
Error: Can't open display: :0

参考资料

https://unix.stackexchange.com/a/515786/287317