WL#5363: Thread Pool Service Interface

In order to allow thread schedulers to be dynamically loaded,
it is necessary to make the following changes to the server:

- Two new service interfaces

- Modifications to InnoDB to inform the thread scheduler of state changes.

- Changes to the VIO subsystem for checking if data is available on a socket.

- Elimination of remains of the old thread pool implementation.

The two new service interfaces introduces are:

my_thread_scheduler
  A service interface to register a thread
  scheduler.

thd_wait
  A service interface to inform thread scheduler
  that the thread is about to start waiting.

In addition, the patch adds code that:

- Add a call to thd_wait for table locks in mysys
  thd_lock.c by introducing a set function that
  can be used to set a callback to be used when
  waiting on a lock and resuming from waiting.

- Calling the mysys set function from the server
  to set the callbacks correctly.

4 files changed, 21 insertions, 1 deletions

diff --git a/vio/vio.c b/vio/vio.c
index 73dd68b938f..210bcdb584b 100644
--- a/vio/vio.c
+++ b/vio/vio.c
@@ -44,6 +44,11 @@ static my_bool no_poll_read(Vio *vio __attribute__((unused)),
 
 #endif
 
+static my_bool has_no_data(Vio *vio __attribute__((unused)))
+{
+  return FALSE;
+}
+
 /*
  * Helper to fill most of the Vio* with defaults.
  */
@@ -83,6 +88,7 @@ static void vio_init(Vio* vio, enum enum_vio_type type,
 
     vio->poll_read      =no_poll_read;
     vio->is_connected   =vio_is_connected_pipe;
+    vio->has_data       =has_no_data;
 
     vio->timeout=vio_win32_timeout;
     /* Set default timeout */
@@ -110,6 +116,7 @@ static void vio_init(Vio* vio, enum enum_vio_type type,
 
     vio->poll_read      =no_poll_read;
     vio->is_connected   =vio_is_connected_shared_memory;
+    vio->has_data       =has_no_data;
 
     /* Currently, shared memory is on Windows only, hence the below is ok*/
     vio->timeout= vio_win32_timeout; 
@@ -137,6 +144,7 @@ static void vio_init(Vio* vio, enum enum_vio_type type,
     vio->timeout	=vio_timeout;
     vio->poll_read      =vio_poll_read;
     vio->is_connected   =vio_is_connected;
+    vio->has_data       =vio_ssl_has_data;
     DBUG_VOID_RETURN;
   }
 #endif /* HAVE_OPENSSL */
@@ -155,6 +163,8 @@ static void vio_init(Vio* vio, enum enum_vio_type type,
   vio->timeout          =vio_timeout;
   vio->poll_read        =vio_poll_read;
   vio->is_connected     =vio_is_connected;
+  vio->has_data=        (flags & VIO_BUFFERED_READ) ?
+                            vio_buff_has_data : has_no_data;
   DBUG_VOID_RETURN;
 }
 
diff --git a/vio/vio_priv.h b/vio/vio_priv.h
index 69eb26083d6..1bfb857b039 100644
--- a/vio/vio_priv.h
+++ b/vio/vio_priv.h
@@ -49,6 +49,7 @@ int vio_close_shared_memory(Vio * vio);
 #endif
 
 void	vio_timeout(Vio *vio,uint which, uint timeout);
+my_bool vio_buff_has_data(Vio *vio);
 
 #ifdef HAVE_OPENSSL
 #include "my_net.h"			/* needed because of struct in_addr */
@@ -62,5 +63,7 @@ void vio_ssl_delete(Vio *vio);
 
 int vio_ssl_blocking(Vio *vio, my_bool set_blocking_mode, my_bool *old_mode);
 
+my_bool vio_ssl_has_data(Vio *vio);
+
 #endif /* HAVE_OPENSSL */
 #endif /* VIO_PRIV_INCLUDED */
diff --git a/vio/viosocket.c b/vio/viosocket.c
index 6c361e4a462..e60fe9bb225 100644
--- a/vio/viosocket.c
+++ b/vio/viosocket.c
@@ -98,6 +98,10 @@ size_t vio_read_buff(Vio *vio, uchar* buf, size_t size)
 #undef VIO_UNBUFFERED_READ_MIN_SIZE
 }
 
+my_bool vio_buff_has_data(Vio *vio)
+{
+  return (vio->read_pos != vio->read_end);
+}
 
 size_t vio_write(Vio * vio, const uchar* buf, size_t size)
 {
diff --git a/vio/viossl.c b/vio/viossl.c
index 0651fd8b7a3..1c6863c9943 100644
--- a/vio/viossl.c
+++ b/vio/viossl.c
@@ -274,6 +274,9 @@ int vio_ssl_blocking(Vio *vio __attribute__((unused)),
   return (set_blocking_mode ? 0 : 1);
 }
 
-
+my_bool vio_ssl_has_data(Vio *vio)
+{
+  return SSL_pending(vio->ssl_arg) > 0 ? TRUE : FALSE;
+}
 
 #endif /* HAVE_OPENSSL */