Factor out the pollset kicking mechanism and eliminate sharding

This change pulls out a separate pollset_kick module, which currently
uses a freelist of pipes dynamically assigned to pollsets when they
enter polling rather than the previous racy sharding mechanism.

We ultimately may wish to eliminate the dynamic assignment for multipoll
sets, but this should be sufficient for the moment.

1 files changed, 68 insertions, 0 deletions

diff --git a/src/core/iomgr/pollset_kick.h b/src/core/iomgr/pollset_kick.h
new file mode 100644
index 0000000000..f088818b9a
--- /dev/null
+++ b/src/core/iomgr/pollset_kick.h
@@ -0,0 +1,68 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef __GRPC_INTERNAL_IOMGR_POLLSET_KICK_H_
+#define __GRPC_INTERNAL_IOMGR_POLLSET_KICK_H_
+
+#include <grpc/support/port_platform.h>
+
+/* This is an abstraction around the typical pipe mechanism for waking up a
+   thread sitting in a poll() style call. */
+
+#ifdef GPR_POSIX_SOCKET
+#include "src/core/iomgr/pollset_kick_posix.h"
+#else
+#error "No pollset kick support on platform"
+#endif
+
+void grpc_pollset_kick_global_init(void);
+void grpc_pollset_kick_global_destroy(void);
+
+void grpc_pollset_kick_init(grpc_pollset_kick_state *kick_state);
+void grpc_pollset_kick_destroy(grpc_pollset_kick_state *kick_state);
+
+/* Must be called before entering poll(). If return value is -1, this consumed
+   an existing kick. Otherwise the return value is an FD to add to the poll set.
+ */
+int grpc_pollset_kick_pre_poll(grpc_pollset_kick_state *kick_state);
+
+/* Consume an existing kick. Must be called after poll returns that the fd was
+   readable, and before calling kick_post_poll. */
+void grpc_pollset_kick_consume(grpc_pollset_kick_state *kick_state);
+
+/* Must be called after pre_poll, and after consume if applicable */
+void grpc_pollset_kick_post_poll(grpc_pollset_kick_state *kick_state);
+
+void grpc_pollset_kick_kick(grpc_pollset_kick_state *kick_state);
+
+#endif /* __GRPC_INTERNAL_IOMGR_POLLSET_KICK_H_ */