Setting mem_limit to restrict the memory usage of BE process is not working

I set the mem_limit to 35% but checked the memory usage still growing after using 35%.
Eventually the memory usage is too high and the BE process will exit abnormally.
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PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
15048 doris 20 0 13.9g 2.6g 4940 S 8.6 8.2 17238:50 java
16127 doris 20 0 17.0g 11.8g 23556 S 5.6 **37.6** 359:08.85 palo_be

[root@be001 ~]# cat /usr/local/doris/be/conf/be.conf |grep mem_limit
mem_limit = 35%

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mem_limit
类型：string
描述：限制BE进程使用服务器最大内存百分比。用于防止BE内存挤占太多的机器内存，该参数必须大于0，当百分大于100%之后，该值会默认为100%。
默认值：80%