1 files changed, 202 insertions, 0 deletions
diff --git a/src/rgw/rgw_aio_throttle.cc b/src/rgw/rgw_aio_throttle.cc
new file mode 100644
index 000000000..8ada6db34
--- /dev/null
+++ b/src/rgw/rgw_aio_throttle.cc
@@ -0,0 +1,202 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab ft=cpp
+
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2018 Red Hat, Inc.
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation. See file COPYING.
+ *
+ */
+
+#include "include/rados/librados.hpp"
+
+#include "rgw_aio_throttle.h"
+
+namespace rgw {
+
+bool Throttle::waiter_ready() const
+{
+  switch (waiter) {
+  case Wait::Available: return is_available();
+  case Wait::Completion: return has_completion();
+  case Wait::Drained: return is_drained();
+  default: return false;
+  }
+}
+
+AioResultList BlockingAioThrottle::get(const RGWSI_RADOS::Obj& obj,
+                                       OpFunc&& f,
+                                       uint64_t cost, uint64_t id)
+{
+  auto p = std::make_unique<Pending>();
+  p->obj = obj;
+  p->id = id;
+  p->cost = cost;
+
+  std::unique_lock lock{mutex};
+  if (cost > window) {
+    p->result = -EDEADLK; // would never succeed
+    completed.push_back(*p);
+  } else {
+    // wait for the write size to become available
+    pending_size += p->cost;
+    if (!is_available()) {
+      ceph_assert(waiter == Wait::None);
+      waiter = Wait::Available;
+      cond.wait(lock, [this] { return is_available(); });
+      waiter = Wait::None;
+    }
+
+    // register the pending write and attach a completion
+    p->parent = this;
+    pending.push_back(*p);
+    lock.unlock();
+    std::move(f)(this, *static_cast<AioResult*>(p.get()));
+    lock.lock();
+  }
+  p.release();
+  return std::move(completed);
+}
+
+void BlockingAioThrottle::put(AioResult& r)
+{
+  auto& p = static_cast<Pending&>(r);
+  std::scoped_lock lock{mutex};
+
+  // move from pending to completed
+  pending.erase(pending.iterator_to(p));
+  completed.push_back(p);
+
+  pending_size -= p.cost;
+
+  if (waiter_ready()) {
+    cond.notify_one();
+  }
+}
+
+AioResultList BlockingAioThrottle::poll()
+{
+  std::unique_lock lock{mutex};
+  return std::move(completed);
+}
+
+AioResultList BlockingAioThrottle::wait()
+{
+  std::unique_lock lock{mutex};
+  if (completed.empty() && !pending.empty()) {
+    ceph_assert(waiter == Wait::None);
+    waiter = Wait::Completion;
+    cond.wait(lock, [this] { return has_completion(); });
+    waiter = Wait::None;
+  }
+  return std::move(completed);
+}
+
+AioResultList BlockingAioThrottle::drain()
+{
+  std::unique_lock lock{mutex};
+  if (!pending.empty()) {
+    ceph_assert(waiter == Wait::None);
+    waiter = Wait::Drained;
+    cond.wait(lock, [this] { return is_drained(); });
+    waiter = Wait::None;
+  }
+  return std::move(completed);
+}
+
+template <typename CompletionToken>
+auto YieldingAioThrottle::async_wait(CompletionToken&& token)
+{
+  using boost::asio::async_completion;
+  using Signature = void(boost::system::error_code);
+  async_completion<CompletionToken, Signature> init(token);
+  completion = Completion::create(context.get_executor(),
+                                  std::move(init.completion_handler));
+  return init.result.get();
+}
+
+AioResultList YieldingAioThrottle::get(const RGWSI_RADOS::Obj& obj,
+                                       OpFunc&& f,
+                                       uint64_t cost, uint64_t id)
+{
+  auto p = std::make_unique<Pending>();
+  p->obj = obj;
+  p->id = id;
+  p->cost = cost;
+
+  if (cost > window) {
+    p->result = -EDEADLK; // would never succeed
+    completed.push_back(*p);
+  } else {
+    // wait for the write size to become available
+    pending_size += p->cost;
+    if (!is_available()) {
+      ceph_assert(waiter == Wait::None);
+      ceph_assert(!completion);
+
+      boost::system::error_code ec;
+      waiter = Wait::Available;
+      async_wait(yield[ec]);
+    }
+
+    // register the pending write and initiate the operation
+    pending.push_back(*p);
+    std::move(f)(this, *static_cast<AioResult*>(p.get()));
+  }
+  p.release();
+  return std::move(completed);
+}
+
+void YieldingAioThrottle::put(AioResult& r)
+{
+  auto& p = static_cast<Pending&>(r);
+
+  // move from pending to completed
+  pending.erase(pending.iterator_to(p));
+  completed.push_back(p);
+
+  pending_size -= p.cost;
+
+  if (waiter_ready()) {
+    ceph_assert(completion);
+    ceph::async::post(std::move(completion), boost::system::error_code{});
+    waiter = Wait::None;
+  }
+}
+
+AioResultList YieldingAioThrottle::poll()
+{
+  return std::move(completed);
+}
+
+AioResultList YieldingAioThrottle::wait()
+{
+  if (!has_completion() && !pending.empty()) {
+    ceph_assert(waiter == Wait::None);
+    ceph_assert(!completion);
+
+    boost::system::error_code ec;
+    waiter = Wait::Completion;
+    async_wait(yield[ec]);
+  }
+  return std::move(completed);
+}
+
+AioResultList YieldingAioThrottle::drain()
+{
+  if (!is_drained()) {
+    ceph_assert(waiter == Wait::None);
+    ceph_assert(!completion);
+
+    boost::system::error_code ec;
+    waiter = Wait::Drained;
+    async_wait(yield[ec]);
+  }
+  return std::move(completed);
+}
+} // namespace rgw