On 11/12/09, Johnny Hung <johnny.hacking@xxxxxxxxx> wrote: > Hi All: > I am writing user space application and need to allocate a > continuous memory. The size is just 64KB and I also need to know the > allocated physical memory address. Is is possible to do it in user > space or it should be done it kernel space? To the best I know, in user space, all kind of memory allocation done via functions like malloc(), mmap(), brk etc never guarantees continous physical memory. Only continous virtual memory. The reason is that they are all basically just reserve or extend existing VMA. The real allocation, which is done on per page basis, is deferred 'til page fault happen. >BTW, how to allocate > continuous physical memory and got it physical address in kernel > space? IIRC, get_free_pages(). I might be wrong though...The return value of this function is the starting virtual address of the page. And to convert it to physical address, IIRC, you can use virt_to_phys() function. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
