Convert to POSIX polled I/O for async; start of cancelable aio.

This eliminates the two threads per pipe that were being used to provide
basic I/O handling, replacing them with a single global thread for now,
that uses poll and nonblocking I/O.  This should lead to great scalability.

The infrastructure is in place to easily expand to multiple polling worker
threads.  Some thought needs to be given about how to scale this to engage
multiple CPUs.  Horizontal scaling may also shorten the poll() lists easing
C10K problem.

We should look into better solutions than poll() for platforms that have
them (epoll on Linux, kqueue on BSD, and event ports on illumos).

Note that the file descriptors start out in blocking mode for now, but
then are placed into non-blocking mode.  This is because the negotiation
phase is not yet callback driven, and so needs to be synchronous.

1 files changed, 7 insertions, 37 deletions

diff --git a/src/platform/posix/posix_aio.h b/src/platform/posix/posix_aio.h
index 797f9e43..9ab322a0 100644
--- a/src/platform/posix/posix_aio.h
+++ b/src/platform/posix/posix_aio.h
@@ -18,43 +18,13 @@
 
 #include "core/nng_impl.h"
 
-typedef struct nni_posix_aioq		nni_posix_aioq;
-typedef struct nni_posix_aiof		nni_posix_aiof;
-typedef struct nni_posix_aio_pipe	nni_posix_aio_pipe;
-typedef struct nni_posix_aio_ep		nni_posix_aio_ep;
 
-// Head structure representing file operations for read/write.  We process
-// the list of aios serially, and each file has its own thread for now.
-struct nni_posix_aioq {
-	nni_list	aq_aios;
-	int		aq_fd;
-	nni_mtx		aq_lk;
-	nni_cv		aq_cv;
-#ifdef NNG_USE_POSIX_AIOTHR
-	nni_thr		aq_thr;
-#endif
-};
-
-struct nni_posix_aio_pipe {
-	int		ap_fd;
-	nni_posix_aioq	ap_readq;
-	nni_posix_aioq	ap_writeq;
-};
-
-struct nni_posix_aio_ep {
-	int		ap_fd;
-	nni_posix_aioq	ap_q;
-};
-
-extern int nni_posix_aio_pipe_init(nni_posix_aio_pipe *, int);
-extern void nni_posix_aio_pipe_fini(nni_posix_aio_pipe *);
-
-// extern int nni_posix_aio_ep_init(nni_posix_aio_ep *, int);
-// extern void nni_posix_aio_ep_fini(nni_posix_aio_ep *);
-extern int nni_posix_aio_read(nni_posix_aio_pipe *, nni_aio *);
-extern int nni_posix_aio_write(nni_posix_aio_pipe *, nni_aio *);
-
-// extern int nni_posix_aio_connect();
-// extern int nni_posix_aio_accept();
+typedef struct nni_posix_pipedesc   nni_posix_pipedesc;
+extern int nni_posix_pipedesc_sysinit(void);
+extern void nni_posix_pipedesc_sysfini(void);
+extern int nni_posix_pipedesc_init(nni_posix_pipedesc **, int);
+extern void nni_posix_pipedesc_fini(nni_posix_pipedesc *);
+extern int nni_posix_pipedesc_read(nni_posix_pipedesc *, nni_aio *);
+extern int nni_posix_pipedesc_write(nni_posix_pipedesc *, nni_aio *);
 
 #endif // PLATFORM_POSIX_AIO_H