Page Frame Allocation: Difference between revisions

These are the algorithmalgorithms that will provide you a new page frame when you'll need it. The client of this algorithm is usually indifferent to which frame is returned, and especially, a request for n frames needn't to return contiguous frames.

* keeping a pointer to the last allocated bit may improve the performance of the next search (keeping information about the fact all the previous bytes were searched unsucessfullyunsuccessfully)

One straightforward way to manage big areas of addresses space is a linked-list (as depicted below). Each "free" region is associated with a descriptor giving its size and its base address. When some space needs to be allocated, the list is scanned for a region being large enough with a "first fit" or "best fit" (or watheverwhatever) algorithm. This was e.g. the way memory was managed by MS-DOS. When memory is allocated, the suitable entry is either removed (the whole region is allocated) or resized (only a portion of the region is allocated).