On 2014/03/19, 11:33 AM, "Oleg Nesterov" <o...@redhat.com> wrote: >On 03/19, Peng Tao wrote: >> >> On Wed, Mar 19, 2014 at 12:23 AM, Oleg Nesterov <o...@redhat.com> wrote: >> > >> > Firtsly, cfs_block_sigs/cfs_block_sigsinv/etc are not exactly right, >> > they need set_current_blocked(). And you can read "old" lockless. >> > >> It seems that set_current_blocked() is not exported. Can we ask to >>export it? > >Why not. If you are going to change this code to use >set_current_blocked(), I'd suggest you to send the "export >set_current_blocked" patch in series. Otherwise, if it is sent > separately, your change will depend on another tree. > >Or you can use sigprocmask(). Actually it should die, but this won't >happen soon and it is already exported. > >> And looking at other similar places like coda_block_signals(), > >Yes, it can have much more users. > >But note that set_current_blocked() can't help you to really block >SIGKILL anyway. > >Could you explain why __l_wait_event() can't use TASK_UNINTERRUPTIBLE >instead of cfs_block_sigsinv(0) ?
The original reason for l_wait_event() not using TASK_UNINTERRUPTIBLE is to avoid the load on the server continually being "num_service_threads" regardless of whether they are actually doing something or not. We added various cases for periodic wakeups and such afterward. l_wait_event() was originally developed for 2.4 kernels, so there may well be better primitives to use today. I'd be happy to move toward replacing l_wait_event() with kernel primitives if possible, but we need to ensure that this is tested sufficiently since it can otherwise be a source of hard-to-find bugs. Cheers, Andreas -- Andreas Dilger Lustre Software Architect Intel High Performance Data Division -- 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/
