diff options
author | jeff <jeff@FreeBSD.org> | 2007-12-16 06:21:20 +0000 |
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committer | jeff <jeff@FreeBSD.org> | 2007-12-16 06:21:20 +0000 |
commit | 4ec9caf00c407884fc51ff18adb8ff16a5eb75c0 (patch) | |
tree | e3b97a4fccf98fcc3311ea54b086b57edb1abb4d /sys/kern/sys_pipe.c | |
parent | 436e8270ebc964cc1f1effe79ac5c10e92e78f7b (diff) | |
download | FreeBSD-src-4ec9caf00c407884fc51ff18adb8ff16a5eb75c0.zip FreeBSD-src-4ec9caf00c407884fc51ff18adb8ff16a5eb75c0.tar.gz |
Refactor select to reduce contention and hide internal implementation
details from consumers.
- Track individual selecters on a per-descriptor basis such that there
are no longer collisions and after sleeping for events only those
descriptors which triggered events must be rescaned.
- Protect the selinfo (per descriptor) structure with a mtx pool mutex.
mtx pool mutexes were chosen to preserve api compatibility with
existing code which does nothing but bzero() to setup selinfo
structures.
- Use a per-thread wait channel rather than a global wait channel.
- Hide select implementation details in a seltd structure which is
opaque to the rest of the kernel.
- Provide a 'selsocket' interface for those kernel consumers who wish to
select on a socket when they have no fd so they no longer have to
be aware of select implementation details.
Tested by: kris
Reviewed on: arch
Diffstat (limited to 'sys/kern/sys_pipe.c')
-rw-r--r-- | sys/kern/sys_pipe.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/sys/kern/sys_pipe.c b/sys/kern/sys_pipe.c index 2a48583..262ef0c 100644 --- a/sys/kern/sys_pipe.c +++ b/sys/kern/sys_pipe.c @@ -524,8 +524,9 @@ pipeselwakeup(cpipe) PIPE_LOCK_ASSERT(cpipe, MA_OWNED); if (cpipe->pipe_state & PIPE_SEL) { - cpipe->pipe_state &= ~PIPE_SEL; selwakeuppri(&cpipe->pipe_sel, PSOCK); + if (!SEL_WAITING(&cpipe->pipe_sel)) + cpipe->pipe_state &= ~PIPE_SEL; } if ((cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio) pgsigio(&cpipe->pipe_sigio, SIGIO, 0); @@ -1354,12 +1355,14 @@ pipe_poll(fp, events, active_cred, td) if (revents == 0) { if (events & (POLLIN | POLLRDNORM)) { selrecord(td, &rpipe->pipe_sel); - rpipe->pipe_state |= PIPE_SEL; + if (SEL_WAITING(&rpipe->pipe_sel)) + rpipe->pipe_state |= PIPE_SEL; } if (events & (POLLOUT | POLLWRNORM)) { selrecord(td, &wpipe->pipe_sel); - wpipe->pipe_state |= PIPE_SEL; + if (SEL_WAITING(&wpipe->pipe_sel)) + wpipe->pipe_state |= PIPE_SEL; } } #ifdef MAC |