1 files changed, 92 insertions, 0 deletions
diff --git a/src/crimson/common/smp_helpers.h b/src/crimson/common/smp_helpers.h
new file mode 100644
index 000000000..c2b7bd964
--- /dev/null
+++ b/src/crimson/common/smp_helpers.h
@@ -0,0 +1,92 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <limits>
+
+#include <seastar/core/smp.hh>
+
+#include "crimson/common/errorator.h"
+#include "crimson/common/utility.h"
+
+namespace crimson {
+
+using core_id_t = seastar::shard_id;
+static constexpr core_id_t NULL_CORE = std::numeric_limits<core_id_t>::max();
+
+auto submit_to(core_id_t core, auto &&f) {
+  using ret_type = decltype(f());
+  if constexpr (is_errorated_future_v<ret_type>) {
+    auto ret = seastar::smp::submit_to(
+      core,
+      [f=std::move(f)]() mutable {
+	return f().to_base();
+      });
+    return ret_type(std::move(ret));
+  } else {
+    return seastar::smp::submit_to(core, std::move(f));
+  }
+}
+
+template <typename Obj, typename Method, typename... Args>
+auto proxy_method_on_core(
+  core_id_t core, Obj &obj, Method method, Args&&... args) {
+  return crimson::submit_to(
+    core,
+    [&obj, method,
+     arg_tuple=std::make_tuple(std::forward<Args>(args)...)]() mutable {
+      return apply_method_to_tuple(obj, method, std::move(arg_tuple));
+    });
+}
+
+/**
+ * reactor_map_seq
+ *
+ * Invokes f on each reactor sequentially, Caller may assume that
+ * f will not be invoked concurrently on multiple cores.
+ */
+template <typename F>
+auto reactor_map_seq(F &&f) {
+  using ret_type = decltype(f());
+  if constexpr (is_errorated_future_v<ret_type>) {
+    auto ret = crimson::do_for_each(
+      seastar::smp::all_cpus().begin(),
+      seastar::smp::all_cpus().end(),
+      [f=std::move(f)](auto core) mutable {
+	return seastar::smp::submit_to(
+	  core,
+	  [&f] {
+	    return std::invoke(f);
+	  });
+      });
+    return ret_type(ret);
+  } else {
+    return seastar::do_for_each(
+      seastar::smp::all_cpus().begin(),
+      seastar::smp::all_cpus().end(),
+      [f=std::move(f)](auto core) mutable {
+	return seastar::smp::submit_to(
+	  core,
+	  [&f] {
+	    return std::invoke(f);
+	  });
+      });
+  }
+}
+
+/**
+ * sharded_map_seq
+ *
+ * Invokes f on each shard of t sequentially.  Caller may assume that
+ * f will not be invoked concurrently on multiple cores.
+ */
+template <typename T, typename F>
+auto sharded_map_seq(T &t, F &&f) {
+  return reactor_map_seq(
+    [&t, f=std::forward<F>(f)]() mutable {
+      return std::invoke(f, t.local());
+    });
+}
+
+}