On Thu, 08 Feb 2007 12:19:45 -0800 (PST) David Miller <[EMAIL PROTECTED]> wrote:
> From: William Cohen <[EMAIL PROTECTED]> > Date: Thu, 08 Feb 2007 11:14:13 -0500 > > > This past week I was playing around with that pahole tool > > (http://oops.ghostprotocols.net:81/acme/dwarves/) and looking at the > > size of various struct in the kernel. I was surprised by the size of > > the task_struct on x86_64, approaching 4K. I looked through the > > fields in task_struct and found that a number of them were declared as > > "unsigned long" rather than "unsigned int" despite them appearing okay > > as 32-bit sized fields. On x86_64 "unsigned long" ends up being 8 > > bytes in size and forces 8 byte alignment. Is there a reason there > > a reason they are "unsigned long"? > > I think at one point we used the atomic bit operations to operate on > things like tsk->flags, and those interfaces require unsigned long as > the type. > > That doesn't appear to be the case any longer, so at a minimum > your tsk->flags conversion to unsigned int should be ok. Yeah, afacit everything in there is OK and happily all the converted-to-32-bit quantities happen to be contiguous with other 32-bit quantities. Most architectures' bitops functions take unsigned long * so if anyone is using bitops on these things we should get to hear about it. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
