On Wed, Feb 19, 2014 at 02:00:21PM -0800, Andrew Morton wrote:
> > I toyed with the idea of changing task_struct.make_it_fail to unsigned too,
> > but only realized I missed that after I'd sent out the diff.
>
> If we're touching the task_struct we could make it a bool.
>
> Or just a single bit(field). task_struct already has a bunch of
> bitfields in it (strangely, they aren't contiguous).
afaics, asides from brk_randomized, they're contiguous, and gcc dtrt..
unsigned int in_execve:1; /* 768:31 4 */
unsigned int in_iowait:1; /* 768:30 4 */
unsigned int no_new_privs:1; /* 768:29 4 */
unsigned int sched_reset_on_fork:1; /* 768:28 4 */
unsigned int sched_contributes_to_load:1; /* 768:27 4
*/
So we could move the COMPAT_BRK ifdef and save 4 bytes for all the people still
using libc5.
(Or those who are for some reason averse to heap randomization).
It's not really worth doing unless you're moving a bunch of other stuff around
in task_struct though, because as it is now, that struct has a bunch of
alignment padding
& holes, so you're not going to save anything.
The other tricky part with reorganizing that struct is that so much of it is
configurable.
Dave
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
