Hi, I'm porting my test memory allocator from i386 to x86_64 (Xeon) systems for learning purposes. It creates zone banks of 4K (single 4K pages) and 64K (16 4K pages virtually contiguous). For this reason, I track them using a bitfield. Since my system has 4GB of ram, allotting 1 bit per 4K page helps me keep track of all the pages in a system having 4GB of ram using only 128K of additional memory. On x86_64, since all memory is mapped from 0xffff810000000000 onwards, I believe if I assign a bit for each 4K page from this address onwards, I can track all pages in the system. However, alloc_pages() returns address like 0xffff810106bce000 which falls out of the linear 4GB range from 0xffff810000000000 onwards. So it seems the memory mapping is not linear. So my question is how do I know: 1) which is the lowest possible kernel virtual address that can ever by allocated to by by alloc_pages/get_free_pages? 2) is the kernel memory virtually contiguous? 3) if the kernel memory is not virtually contiguous, how to I use simple bitfield and address math to keep track of these disperse addresses? Thanks Rock ____________________________________________________________________________________ Food fight? Enjoy some healthy debate in the Yahoo! Answers Food & Drink Q&A. http://answers.yahoo.com/dir/?link=list&sid=396545367 -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
