![]() ![]() If you want all the nonzero entries, first read /proc/PID/maps to find what ranges are mapped. Or if you want information for a range, read some multiple of 8 bytes. So ptep->pte isn't actually giving me a physical address. The right way to use the pagemap file is to know what virtual address you're looking for, seek to it, and read 8 bytes. Yes, the page tables are stored in the kernel address space. The page table entry also contains various bits for access rights and other stuff. It's not a text file, so the entries that aren't zero aren't likely to look good on your terminal either. It's not hung, it's doing what you asked. A bunch of \0's output to a terminal cause no visible effect. A speed test on my own computer suggests about 21 years.Īnd it's mostly going to be filled with zeros (for all the virtual addresses that aren't mapped in the process). The physical address corresponding to the virtual address is often referenced by the underlying physical page frame. The architecture code for each supported architecture will then map this to the restrictions of the hardware. Catting the whole thing is going to take a long time. Linux defines page tables as a hierarchy which is currently five levels in height. When a binary is first started, its handled by a structure called bprm. Lets consider X86 architecture as an example. So the full pagemap file will be 2**52 entries of 8 bytes each. I am recently studying Linux kernel and I have a question regarding how user processs page table is first updated by the kernel. 4 Driver mmap operation Page table creation. ![]() Huge pages are not supported and thats all. With 4096-byte pages and a 64-bit virtual address space, there are 2**52 pages. In any case, are you interested with the kernel API to walk the page tables haggaie. According to the documentation, /proc/PID/pagemap contains one 64-bit value for each virtual page. ![]()
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