Hi loody, On Mon, Nov 7, 2011 at 5:16 AM, loody <milo...@gmail.com> wrote: ...snip... >>> 1. Are all struct page 32-bit aligned? >> >> Certainly, I would expect any structures found in the system memory map to >> be so aligned, yes. If you've created an arbitrary one elsewhere I'm only >> 99% sure it would be. >> >>> If so, where is this part of code for handleing struct page be 32-bits >>> aligned? >> >> Note that the size of struct page is carefully considered, and that they >> are packed as densely as possible, both externally and internally. No >> lesser alignment would make sense. > I found kernel stealing LSB of page_link to put additional > information, such as sg_is_chain and sg_is_last. > > That means the address of all pages have to be at least 4byte alignment. > But I didn't see any additional attribute added at the end of struct > or any precaution to take care this.
This is done automatically by the compiler. http://en.wikipedia.org/wiki/Data_structure_alignment -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
