On 8 January 2015 at 12:10, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > > On 08/01/2015 10:16, Fam Zheng wrote: >> Unlike ppoll(2), which accepts a timespec argument "timeout_ts" to >> specify the timeout, epoll_wait(2) and epoll_pwait(2) expect a >> microsecond timeout in int type. >> >> This is an obstacle for applications in switching from ppoll to epoll, >> if they want nanosecond resolution in their event loops. >> >> Therefore, adding this variation of epoll wait interface, giving user an >> option with *both* advantages, is a reasonable move: there could be >> constantly scalable performance polling many fds, while having a >> nanosecond timeout precision (assuming it has properly set up timer >> slack with prctl(2)). >> >> Signed-off-by: Fam Zheng <famz@xxxxxxxxxx> >> --- >> fs/eventpoll.c | 24 ++++++++++++++++++++++++ >> include/linux/syscalls.h | 4 ++++ >> kernel/sys_ni.c | 3 +++ >> 3 files changed, 31 insertions(+) > > As mentioned by Miklos in the non-resent version, please add a flags > argument. Invalid flags should return -EINVAL. > > In fact, we could already use the flags argument to specify an absolute > timeout, which is a nice thing to have for QEMU too. Nice! It looks like we found this iteration of "failure to include a flags argument is a mistake" already! Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
