Java:什么决定了Linux机器中可能的最大最大堆大小 [英] Java: what determines the maximum max heap size possible in a linux machine
问题描述
我有两台Linux机器(均为VM)，一台具有12GB内存，另一台具有8GB内存.
我试图在两台机器上启动相同的Java程序，并且最大可能的最大堆大小(使用-Xmx标志).以下是我得到的结果.
- 12GB机器:9460MB
- 8GB机器:4790MB
如果我指定的最大堆大小超出限制，我将得到以下错误.
Error occurred during initialization of VM
Could not allocate metaspace: 1073741824 bytes
我检查了两个系统中的可用内存(使用free命令)，然后得到关注.
- 12GB机器:大约3GB可用空间.
- 8GB机器:大约4GB可用空间.
我的问题是，什么决定了可以启动Java程序的最大最大堆大小，这不会导致上述错误? (当程序出现上述错误时，系统有足够的内存来分配1073741824个字节的内存)
我用ravindra给出的线索做了一些实验，发现最大最大堆大小与系统中可用的总虚拟内存有直接关系. /p>
可以通过以下方式找到系统中的总虚拟内存(以KB为单位):
ulimit-v
总虚拟内存可以通过以下方式更改:
ulimit -v <new amount in KB>
最大可能的最大堆大小比虚拟内存少大约2GB.如果使用ulimit -v unlimited指定无限的虚拟内存，则可以为最大堆大小指定任何较大的值.
I have two linux machines (both are VMs), one having 12GB memory and other having 8GB memory.
I tried to start the same java program on both machines, with maximum max heap size possible (using -Xmx flag). Following are the results I got.
- 12GB machine: 9460MB
- 8GB machine: 4790MB
If I specify a max heap size beyond above limits, I get below error.
Error occurred during initialization of VM
Could not allocate metaspace: 1073741824 bytes
I checked the free memory in two systems (using free command), and I got following.
- 12GB machine: approximately 3GB free.
- 8GB machine: approximately 4GB free.
My question is, what determines the maximum max heap size a java program can be started with, which would not result in above mentioned error? (System had sufficient memory to allocate 1073741824 bytes of memory when the program gave above error)
I did some experiments with the clues given by ravindra and found that the maximum max heap size has a direct relationship with the total virtual memory available in the system.
Total virtual memory in the system can be found (in KB) with:
ulimit-v
Total virtual memory can be altered with:
ulimit -v <new amount in KB>
The maximum max heap size possible was approximately 2GB less than the virtual memory. If you specify unlimited virtual memory using ulimit -v unlimited, You can specify any large value for the max heap size.
这篇关于Java:什么决定了Linux机器中可能的最大最大堆大小的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
