Fix a subtle race condition in map_handle on Windows where if many threads are currently allocating and freeing maps, it could rarely occur that one thread would free the map of another thread. The newly rewritten v3 of win32_maps_apply() we really, really hope is the last time!

1 files changed, 93 insertions, 0 deletions

diff --git a/test/tests/issue0009.cpp b/test/tests/issue0009.cpp
new file mode 100644
index 00000000..ca15cf43
--- /dev/null
+++ b/test/tests/issue0009.cpp
@@ -0,0 +1,93 @@
+/* Integration test kernel for issue #9 map_handle and mapped_file_handle are very slow with large address reservations on Windows
+(C) 2020 Niall Douglas <http://www.nedproductions.biz/> (2 commits)
+File Created: Sept 2020
+
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License in the accompanying file
+Licence.txt or at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+
+Distributed under the Boost Software License, Version 1.0.
+    (See accompanying file Licence.txt or copy at
+          http://www.boost.org/LICENSE_1_0.txt)
+*/
+
+#include "../test_kernel_decl.hpp"
+
+static inline void TestIssue09a()
+{
+  namespace llfio = LLFIO_V2_NAMESPACE;
+  auto fh = llfio::file_handle::temp_file().value();
+  fh.truncate(1).value();
+  auto sh = llfio::section_handle::section(fh).value();
+  sh.truncate(1ULL << 40ULL).value();
+  auto mh = llfio::map_handle::map(sh, 1ULL << 35ULL).value();
+  auto *addr1 = mh.address();
+  mh.truncate(1ULL << 36ULL).value();
+  {
+    auto *addr2 = mh.address();
+    BOOST_CHECK(addr1 == addr2);
+  }
+  mh.truncate(1ULL << 37ULL).value();
+  {
+    auto *addr2 = mh.address();
+    BOOST_CHECK(addr1 == addr2);
+  }
+  mh.truncate(1ULL << 38ULL).value();
+  {
+    auto *addr2 = mh.address();
+    BOOST_CHECK(addr1 == addr2);
+  }
+  mh.truncate(1ULL << 39ULL).value();
+  {
+    auto *addr2 = mh.address();
+    BOOST_CHECK(addr1 == addr2);
+  }
+  mh.truncate(1ULL << 40ULL).value();
+  {
+    auto *addr2 = mh.address();
+    BOOST_CHECK(addr1 == addr2);
+  }
+  auto begin = std::chrono::steady_clock::now();
+  mh.close().value();
+  sh.close().value();
+  fh.close().value();
+  auto end = std::chrono::steady_clock::now();
+  auto diff = std::chrono::duration_cast<std::chrono::milliseconds>(end - begin).count();
+  std::cout << "Closing a map_handle (file) with six, appended, very large reservations up to 2^40 took " << diff << "ms." << std::endl;
+  BOOST_CHECK(diff < 250);
+}
+
+static inline void TestIssue09b()
+{
+  namespace llfio = LLFIO_V2_NAMESPACE;
+  auto mh = llfio::map_handle::reserve(1ULL << 43ULL).value();
+  const auto sixth = mh.length() / 6;
+  mh.commit({mh.address() + sixth * 0, 1}).value();
+  mh.commit({mh.address() + sixth * 1, 1}).value();
+  mh.commit({mh.address() + sixth * 2, 1}).value();
+  mh.commit({mh.address() + sixth * 3, 1}).value();
+  mh.commit({mh.address() + sixth * 4, 1}).value();
+  mh.commit({mh.address() + sixth * 5, 1}).value();
+  auto begin = std::chrono::steady_clock::now();
+  mh.do_not_store({mh.address(), mh.length()}).value();
+  auto end = std::chrono::steady_clock::now();
+  auto diff = std::chrono::duration_cast<std::chrono::milliseconds>(end - begin).count();
+  std::cout << "Discard a map_handle (reservation) with six small commits within a reservation of 2^43 took " << diff << "ms." << std::endl;
+  BOOST_CHECK(diff < 250);
+}
+
+KERNELTEST_TEST_KERNEL(regression, llfio, issues, 9a,
+                       "Tests issue #9 map_handle and mapped_file_handle are very slow with large address reservations on Windows", TestIssue09a())
+KERNELTEST_TEST_KERNEL(regression, llfio, issues, 9b,
+                       "Tests issue #9 map_handle and mapped_file_handle are very slow with large address reservations on Windows", TestIssue09b())