On Tue, Jul 19, 2011 at 11:26 PM, mindentropy <mindentropy@xxxxxxxxx> wrote: > Hi, > When I mmap pages via remap_pfn_page method would the physical frames > assigned the linear address be contiguous? If yes what would happen if I mmap > a huge range? > > Thanks. > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > When I mmap pages via remap_pfn_page method would the physical frames > assigned the linear address be contiguous? The place where you typically call remap_pfn_page is mmap handler of your device driver. And you want to assign device memory to user space. Note that the memory (physical pages) might be already allocated and there is no requirement for them to have a kernel linear address assigned to them. For example, on i386, you might allocate pages with from high memory and remap them. These pages may not have kernel linear address. remap_pfn_range is just going to established a secondary virtual address mapping for these pages into the caller process' page tables, irrespective of whether these pages have kernel linear address or not. > If yes what would happen if I mmap a huge range? huge range means you already have huge physical memory to be mapped and user space process has huge virtual memory area to accomodate that. Note that is mapping is specific to one particular process (or threads sharing process address space) so it is fairly possible to establish mmap. Rajat _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
