virt:virtual Memory Usage
1. The process "required" virtual memory size, including the library, code, data, etc. used by the process
2, if the process to apply for 100m of memory, but the actual use of only 10m, then it will grow 100m, rather than the actual use of the volume
res:resident Memory usage resident RAM
1. The memory size currently used by the process, but does not include swap out
2. Sharing with other processes
3, if the application of 100m of memory, the actual use of 10m, it only grows 10m, and virt opposite
4, about the memory consumption of the library, it only statistics the size of the loaded library file memory
shr:shared Memory
1, in addition to the shared memory of the process itself, also includes the shared memory of other processes
2, although the process uses only a few shared library functions, but it contains the entire size of the shared library
3. Calculate the physical memory size formula that a process occupies: res–shr
4, swap out, it will fall down
DATA
1, the memory occupied by the data. If top is not displayed, press the F key to display it.
2, the real data space required by the program is really in operation to use.
The meaning of the top command virt,res,shr,data
