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Can the kernel handle a page fault?
From Intel CPU point of view: yes, it is possible. Not all addresses are available (mapped), so you may get a page fault. Kernel should distinguish the origin of the fault. Kernel could access user space memory (e.g. to clone a process), so it could cause page faults.
Can kernel memory be paged out?
Paging happens only to user space memory from processes. Kernel memory space is always mapped to physical memory and never paged out.
Which page replacement algorithm is used in Linux?
Least Recently Used
Least Recently Used (LRU) is the algorithm which is currently implemented in the Linux kernel [19]. LRU replaces those pages which are not used recently or the oldest pages. The algorithm maintains two lists namely active list and inactive list to facilitate the page replacement [19].
Why is kernel not paged?
Originally Answered: * Why is kernel memory is not pageable? Because a lot of kernel code runs in hardware interrupt handlers and critical regions where you can’t page in data from disk. There is always some code that needs to be available in physical memory with pinned addresses.
How do I reduce the cost of paging to disk?
One option to reduce paging activity is to add memory. Adding memory reduces the likelihood that the system will rely solely on the hard disk for virtual memory. You can monitor your system’s changing memory requirements and properly configure the paging file to maximize paging performance.
How does operating system handle page fault?
Operating system finds that a page fault has occurred and tries to find out which virtual page is needed. If frame selected is dirty, page is scheduled for transfer to disk, context switch takes place, fault process is suspended and another process is made to run until disk transfer is completed.
What happens when there is a page fault?
What happens when a page fault occurs is that the thread that experienced the page fault is put into a Wait state while the operating system finds the specific page on disk and restores it to physical memory. When a thread attempts to reference a nonresident memory page, a hardware interrupt occurs that halts the executing program.
How is page fault handling in operating system?
Page Fault Handling in Operating System. A page fault occurs when a program attempts to access data or code that is in its address space, but is not currently located in the system RAM. So when page fault occurs then following sequence of events happens :
When does a page fault occur in virtual memory?
Today, we’re going to take a look at one of the most common problems when dealing with virtual memory – the Page Fault. A page fault occurs when a program requests an address on a page that is not in the current set of memory resident pages.
What’s the difference between minor and major page fault?
When the CPU needs to access a page that isn’t in memory it raises a page fault. A major page fault is one that can only be satisfied by accessing the disk. A minor page fault can be satisfied by sharing pages that are already in memory. Swapping occurs when pages are written to the disk to free memory so that a major page fault can be satisfied.