Commit charge

Concept in operating system-level memory management In computing, commit charge is a term used in Microsoft Windows operating systems to describe the total amount of virtual memory of all processes that must be backed by either physical memory or the page file. Through the process of paging, the contents of this virtual memory may move between physical memory and the page file, but it cannot exceed the sum of sizes of those two. As a percentage, commit charge is the utilization of this limit. Virtual memory not related to commit charge includes virtual memory backed by files and all-zero pages backed by nothing. Metrics The Windows Task Manager utility for Windows XP and Server 2003, in its Performance tab, shows three counters related to commit charge: Total is the amount of pagefile-backed virtual address space in use, i.e., the current commit charge. This is composed of main memory (RAM) and disk (pagefiles). The corresponding performance counter is called "Committed Bytes". Limit is the maximum possible value for Total; it is the sum of the current pagefile size plus the physical memory available for pageable contents (this excludes RAM that is assigned to non-pageable areas).