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What is minor page fault?
A minor page fault occurs when a process needs data that is in memory and is assigned to another process. Minor page faults share memory pages between multiple processes – no additional data needs to be read from disk to memory.
What is minor and major page fault?
When a process needs a page that is no longer mapped or no longer in memory, a fault is generated. A minor fault means the page is in memory but not allocated to the requesting process or not marked as present in the memory management unit. A major fault means the page in no longer in memory.
How does a page fault occur?
A page fault occurs when a program attempts to access a block of memory that is not stored in the physical memory, or RAM. The fault notifies the operating system that it must locate the data in virtual memory, then transfer it from the storage device, such as an HDD or SSD, to the system RAM.
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.
How to view the number of minor page faults in Linux?
A minor fault occurs due to page allocation. You can use standard Linux commands such as ps, top, time, and sar to view page faults for all process or specific process. Use the ps command to view page faults for PID #1, enter: min_flt : Number of minor page faults.
What happens when the number of page faults goes down?
Once the number of page faults gone down the performance of the daemons and the entire Linux operating system will go up. Linux (and most Unix like) system uses a virtual memory into a physical address space.
What are the commands for page faults in Linux?
A minor fault occurs due to page allocation. You can use standard Linux commands such as ps, top, time, and sar to view page faults for all process or specific process.