From 3af70e75c3e54d7d6af23d22af73dcf917c4f2f6 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Fri, 7 Dec 2018 10:13:29 -0800
Subject: [PATCH] ircd::ctx: Minor cleanup / struct packing / type.

---
 include/ircd/ctx/ctx.h |  2 +-
 ircd/ctx.cc            | 56 +++++++++++++++++++++---------------------
 ircd/ctx.h             | 10 +++++---
 3 files changed, 35 insertions(+), 33 deletions(-)

diff --git a/include/ircd/ctx/ctx.h b/include/ircd/ctx/ctx.h
index 747da6b41..0e6b62ea6 100644
--- a/include/ircd/ctx/ctx.h
+++ b/include/ircd/ctx/ctx.h
@@ -49,7 +49,7 @@ namespace ircd::ctx
 	string_view name(const ctx &);               // User's optional label for context
 	const size_t &stack_max(const ctx &);        // Returns stack size allocated for ctx
 	const size_t &stack_at(const ctx &);         // Stack at last sleep (also see this_ctx.h)
-	const int64_t &notes(const ctx &);           // Peeks at internal semaphore count
+	const int32_t &notes(const ctx &);           // Peeks at internal semaphore count
 	const uint64_t &yields(const ctx &);         // Context switching counter
 	const ulong &cycles(const ctx &);            // Accumulated tsc (not counting cur slice)
 	bool interruptible(const ctx &) noexcept;    // Context can throw at interruption point
diff --git a/ircd/ctx.cc b/ircd/ctx.cc
index 66eb3daa5..37483d15e 100644
--- a/ircd/ctx.cc
+++ b/ircd/ctx.cc
@@ -118,33 +118,6 @@ catch(const std::exception &e)
 	return;
 }
 
-/// Direct context switch to this context.
-///
-/// This currently doesn't work yet because the suspension state of this
-/// context has to be ready to be jumped to and that isn't implemented yet.
-void
-ircd::ctx::ctx::jump()
-{
-	assert(this->yc);
-	assert(current != this);                  // can't jump to self
-
-	auto &yc(*this->yc);
-	auto &target(*yc.coro_.lock());
-
-	// Jump from the currently running context (source) to *this (target)
-	// with continuation of source after target
-	{
-		current->notes = 0; // Unconditionally cleared here
-		const continuation continuation;
-		target();
-	}
-
-	assert(current != this);
-	assert(current->notes == 1); // notes = 1; set by continuation dtor on wakeup
-
-	interruption_point();
-}
-
 /// Yield (suspend) this context until notified.
 ///
 /// This context must be currently running otherwise bad things. Returns false
@@ -180,6 +153,33 @@ ircd::ctx::ctx::wait()
 	return true;
 }
 
+/// Direct context switch to this context.
+///
+/// This currently doesn't work yet because the suspension state of this
+/// context has to be ready to be jumped to and that isn't implemented yet.
+void
+ircd::ctx::ctx::jump()
+{
+	assert(this->yc);
+	assert(current != this);                  // can't jump to self
+
+	auto &yc(*this->yc);
+	auto &target(*yc.coro_.lock());
+
+	// Jump from the currently running context (source) to *this (target)
+	// with continuation of source after target
+	{
+		current->notes = 0; // Unconditionally cleared here
+		const continuation continuation;
+		target();
+	}
+
+	assert(current != this);
+	assert(current->notes == 1); // notes = 1; set by continuation dtor on wakeup
+
+	interruption_point();
+}
+
 /// Notifies this context to resume (wake up from waiting).
 ///
 /// Returns true if this note was the first note received by this context
@@ -465,7 +465,7 @@ ircd::ctx::yields(const ctx &ctx)
 }
 
 /// Returns the notification count for `ctx`
-const int64_t &
+const int32_t &
 ircd::ctx::notes(const ctx &ctx)
 {
 	return ctx.notes;
diff --git a/ircd/ctx.h b/ircd/ctx.h
index 9787f322c..4d8d8c3ec 100644
--- a/ircd/ctx.h
+++ b/ircd/ctx.h
@@ -40,16 +40,18 @@ struct ircd::ctx::profile
 struct ircd::ctx::ctx
 :instance_list<ctx>
 {
+	using flags_t = std::underlying_type<context::flags>::type;
+
 	static uint64_t id_ctr;                      // monotonic
 
 	uint64_t id {++id_ctr};                      // Unique runtime ID
 	const char *name {nullptr};                  // User given name (optional)
-	context::flags flags {(context::flags)0};    // User given flags
+	flags_t flags {0};                           // User given flags
+	int32_t notes {0};                           // norm: 0 = asleep; 1 = awake; inc by others; dec by self
 	boost::asio::io_service::strand strand;      // mutex/serializer
 	boost::asio::steady_timer alarm;             // acting semaphore (64B)
 	boost::asio::yield_context *yc {nullptr};    // boost interface
 	continuation *cont {nullptr};                // valid when asleep; invalid when awake
-	int64_t notes {0};                           // norm: 0 = asleep; 1 = awake; inc by others; dec by self
 	ircd::ctx::stack stack;                      // stack related structure
 	ircd::ctx::profile profile;                  // prof related structure
 	list::node node;                             // node for ctx::list
@@ -62,10 +64,10 @@ struct ircd::ctx::ctx
 	bool termination_point(std::nothrow_t);      // Check for terminate
 	void interruption_point();                   // throws interrupted or terminated
 
-	bool wait();                                 // yield context to ios queue (returns on this resume)
-	void jump();                                 // jump to context directly (returns on your resume)
 	void wake();                                 // jump to context by queueing with ios (use note())
 	bool note();                                 // properly request wake()
+	void jump();                                 // jump to context directly (returns on your resume)
+	bool wait();                                 // yield context to ios queue (returns on this resume)
 
 	void operator()(boost::asio::yield_context, const std::function<void ()>) noexcept;