Find out how many pages of memory a process uses on linux

I need to find out how many pages of memory a process allocates? Each page 开发者_开发知识库is 4096, the process memory usage I'm having some problems locating the correct value. When I'm looking in the gome-system-monitor there are a few values to choose from under memory map.

Thanks.

The point of this is to divide the memory usage by the page count and verify the page size.

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It's hard to figure exact amount of memory allocated correctly: there are pages shared with other processes (r/o parts of libraries), never used memory allocated by brk and anonymous mmap, mmaped file which are not fetched from disk completely due to efficient processing algorithms which touch only small part of file etc, swapped out pages, dirty pages to-be-written-on-disk etc.

If you want to deal with all this complexity and figure out True count of pages, the detailed information is available at /proc/<pid>/smaps, and there are tools, like mem_usage.py or smem.pl (easily googlable) to turn it into more-or-less usable summary.

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This would be the "Resident Set Size", assuming you process doesn't use swap.

Note that a process may allocate far more memory ("Virtual Memory Size"), but as long as it don't writes to the memory, it is not represented by physical memory, be it in RAM or on the disk.

Some system tools, like top, display a huge value for "swap" for each process - this is of course completly wrong, the value is the difference between VMS and RSS and most likely those unused, but allocated, memory pages.