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Full Discussion: Shared memory in linux
Operating Systems Linux Red Hat Shared memory in linux Post 302404518 by jim mcnamara on Tuesday 16th of March 2010 05:50:55 PM
Old 03-16-2010
Shared memory is physical memory that is used by two or more different processes at the same time.

Ex: shared libraries. This is code that gets loaded into memory, and all processes running on the system see it an use it at the same time.
 

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unlockable_mem(5)						     OBSOLETE							 unlockable_mem(5)

NAME
unlockable_mem - OBSOLETE kernel tunable parameter DESCRIPTION
The tunable is obsolete and has been removed. Memory locking allows the privileged user to specify which pages need to remain in memory, and unaffected by the swap process. This fea- ture allows you to ensure that memory access times are unaffected by delays introduced by memory paging and swapping. For example, locking is a tool provided to privileged users on a system that is short on physical memory. Instead of having these privileged processes swap like the rest of the processes, they can lock portions of their address space. Once the pages are locked in for the privileged processes, they will no longer have to worry about memory contention. The unprivileged processes however, will have to compete for memory. provides you with a limiting factor on this privileged behavior, by setting the amount of memory which cannot be locked by user processes. WARNINGS
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parameter values. After installation, some tunable parameters may no longer be at the default or recommended values. For information about the effects of installation on tun- able values, consult the documentation for the kernel software being installed. For information about optional kernel software that was factory installed on your system, see at AUTHOR
was developed by HP. Tunable Kernel Parameters unlockable_mem(5)
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