Contents
How to get memory usage information from proc?
For a given process in /proc/ /smaps, for a given mapping entry what are: Is Shared_Clean + Shared_Dirty the amount of memory that is shared with other processes? So it is like shared RSS? Similarly is Private_Clean + Private_Dirty the amount of memory that is available for only one process? So it is like private RSS?
Where do I find proc / pid / maps in Linux?
See also the entry for /proc/PID/maps in the Linux kernel documentation, Understanding Linux /proc/id/maps and /proc/$pid/maps shows pages with no rwx permissions on x86_64 linux on Stack Overflow. Thanks for contributing an answer to Unix & Linux Stack Exchange!
How is shared memory similar to memory mapped files?
Shared memory is similar to file mapping, and the user can map several regions of a shared memory object, just like with memory mapped files. In some operating systems, like Windows, shared memory is an special case of file mapping, where the file mapping object accesses memory backed by the system paging file.
How does shared memory work in C + + applications?
Reuse of C++ memory utilities (STL containers, algorithms) in files. Shared memory between two or more applications. Allows efficient work with a large files, without loading the whole file into memory If several processes use the same file mapping to create mapped regions of a file, each process’ views contain identical copies of the file on disk.
What does the / proc / PID / smaps extension do?
The /proc/PID/smaps is an extension based on maps, showing the memory consumption for each of the process’s mappings. For each mapping (aka Virtual Memory Area, or VMA) there is a series of lines such as the following:
Where does the information in PMAP come from?
This includes both shared and non-shared memory (though in most cases other than forking servers, shared memory consists of memory-mapped files only). The information displayed by pmap comes from /proc/ PID /maps and /proc/ PID /smaps. That is the real memory usage of the process — it can’t be summarized by a single number.
How to get information about a process’memory usage?
RSS is the total number of pages, shared or not, currently mapped into the process. So Shared_Clean + Shared_Dirty would be the shared part of the RSS (i.e. the part of RSS that is also mapped into other processes), and Private_Clean + Private_Dirty the private part of RSS (i.e. only mapped in this process).