Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
I’m studying O.S,
just wondering about who create page table for process, I guess OS create it for each process, if I’m not wrong,
now here’s my question, since the OS handle the create and maintain of page table, how come there’s a situation that page table is larger than the program required??( and then a valid-invalid bit is now required),
but imagine, if there’s no such situation, there’s no need for this extra bit flag, am I correct?
please help me get out of this marsh, thanks a lot!!
Imagine the opposite of what you describe. Imagine the page table is exactly large enough for what the program requested.
What happens when the program decides to allocate additional memory? The page table must be grown.
If the program deallocates memory, the page table would have to be immediately shrunk.
That approach is potentially expensive if there are many allocations and deallocations.