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Second Level Address Translation (SLAT), also known as nested paging, is a hardware-assisted virtualization technology which makes it possible to avoid the overhead associated with software-managed shadow page tables.
Instruction set extensions that have been added to the x86 instruction set in order to support hardware virtualization.These extensions provide instructions for entering and leaving a virtualized execution context and for loading virtual-machine control structures (VMCSs), which hold the state of the guest and host, along with fields which control processor behavior within the virtual machine.
Users of VirtualBox can load multiple guest OSes under a single host operating-system (host OS). Each guest can be started, paused and stopped independently within its own virtual machine (VM). The user can independently configure each VM and run it under a choice of software-based virtualization or hardware assisted virtualization if the ...
The MMU detects the page fault, but the operating system's kernel handles the exception by making the required page accessible in the physical memory or denying an illegal memory access. Valid page faults are common and necessary to increase the amount of memory available to programs in any operating system that uses virtual memory , such as ...
Nested page tables can be implemented to increase the performance of hardware virtualization. By providing hardware support for page-table virtualization , the need to emulate is greatly reduced. For x86 virtualization the current choices are Intel 's Extended Page Table feature and AMD 's Rapid Virtualization Indexing feature.
A paging system makes efficient decisions on which memory to relegate to secondary storage, leading to the best use of the installed RAM. In addition the operating system may provide services to programs that envision a larger memory, such as files that can grow beyond the limit of installed RAM.
The pages in the page cache are divided in an "active" set and an "inactive" set. Both sets keep a LRU list of pages. In the basic case, when a page is accessed by a user-space program it is put in the head of the inactive set. When it is accessed repeatedly, it is moved to the active list.
In computer science, thrashing occurs in a system with virtual memory when a computer's real storage resources are overcommitted, leading to a constant state of paging and page faults, slowing most application-level processing. [1] This causes the performance of the computer to degrade or even collapse. The situation can continue indefinitely ...