1 files changed, 71 insertions, 0 deletions
diff --git a/src/seastar/demos/block_discard_demo.cc b/src/seastar/demos/block_discard_demo.cc
new file mode 100644
index 00000000..a1fbcfd9
--- /dev/null
+++ b/src/seastar/demos/block_discard_demo.cc
@@ -0,0 +1,71 @@
+/*
+ * This file is open source software, licensed to you under the terms
+ * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
+ * distributed with this work for additional information regarding copyright
+ * ownership.  You may not use this file except in compliance with the License.
+ *
+ * You may obtain a copy of the License 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.
+ */
+/*
+ * Copyright (C) 2014 Cloudius Systems, Ltd.
+ */
+
+#include <algorithm>
+#include <seastar/core/app-template.hh>
+#include <seastar/core/future-util.hh>
+#include <seastar/core/file.hh>
+#include <seastar/core/reactor.hh>
+#include <iostream>
+
+using namespace seastar;
+
+namespace bpo = boost::program_options;
+
+struct file_test {
+    file_test(file&& f) : f(std::move(f)) {}
+    file f;
+    semaphore sem = { 0 };
+};
+
+int main(int ac, char** av) {
+    app_template app;
+    app.add_options()
+        ("dev", bpo::value<std::string>(), "e.g. --dev /dev/sdb")
+        ;
+
+    return app.run_deprecated(ac, av, [&app] {
+        static constexpr auto max = 10000;
+        auto&& config = app.configuration();
+        auto filepath = config["dev"].as<std::string>();
+
+        open_file_dma(filepath, open_flags::rw | open_flags::create).then([] (file f) {
+            auto ft = new file_test{std::move(f)};
+
+            ft->f.stat().then([ft] (struct stat st) mutable {
+                assert(S_ISBLK(st.st_mode));
+                auto offset = 0;
+                auto length = max * 4096;
+                ft->f.discard(offset, length).then([ft] () mutable {
+                    ft->sem.signal();
+                });
+            });
+
+            ft->sem.wait().then([ft] () mutable {
+                return ft->f.flush();
+            }).then([ft] () mutable {
+                std::cout << "done\n";
+                delete ft;
+                engine().exit(0);
+            });
+        });
+    });
+}