ircd::ctx: Add nice/ionice values to context.

include/ircd/ctx/ctx.h

@@ -50,6 +50,8 @@ namespace ircd::ctx
 	const int32_t &notes(const ctx &) noexcept;     // Peeks at internal semaphore count
 	const uint64_t &epoch(const ctx &) noexcept;    // Context switching counter
 	const ulong &cycles(const ctx &) noexcept;      // Accumulated tsc (not counting cur slice)
+	const int8_t &ionice(const ctx &) noexcept;     // IO priority nice-value
+	const int8_t &nice(const ctx &) noexcept;       // Scheduling priority nice-value
 	bool interruptible(const ctx &) noexcept;       // Context can throw at interruption point
 	bool interruption(const ctx &) noexcept;        // Context was marked for interruption
 	bool termination(const ctx &) noexcept;         // Context was marked for termination
@@ -59,6 +61,8 @@ namespace ircd::ctx
 	bool waiting(const ctx &) noexcept;             // started() && !finished() && !running()
 	bool queued(const ctx &) noexcept;              // !running() && notes() > 0
 
+	int8_t ionice(ctx &, const int8_t &);           // IO priority nice-value
+	int8_t nice(ctx &, const int8_t &);             // Scheduling priority nice-value
 	void interruptible(ctx &, const bool &);        // False for interrupt suppression.
 	void interrupt(ctx &);                          // Interrupt the context.
 	void terminate(ctx &);                          // Interrupt for termination.

ircd/ctx.cc

@@ -512,6 +512,22 @@ ircd::ctx::interruptible(ctx &ctx,
 		ctx.flags |= context::NOINTERRUPT;
 }
 
+int8_t
+ircd::ctx::nice(ctx &ctx,
+                const int8_t &val)
+{
+	ctx.nice = val;
+	return ctx.nice;
+}
+
+int8_t
+ircd::ctx::ionice(ctx &ctx,
+                  const int8_t &val)
+{
+	ctx.ionice = val;
+	return ctx.ionice;
+}
+
 /// !running() && notes > 0
 [[gnu::hot]]
 bool
@@ -593,6 +609,24 @@ noexcept
 	return prof::get(ctx, prof::event::CYCLES);
 }
 
+/// Returns the IO priority nice-value
+[[gnu::hot]]
+const int8_t &
+ircd::ctx::ionice(const ctx &ctx)
+noexcept
+{
+	return ctx.ionice;
+}
+
+/// Returns the context scheduling priority nice-value
+[[gnu::hot]]
+const int8_t &
+ircd::ctx::nice(const ctx &ctx)
+noexcept
+{
+	return ctx.nice;
+}
+
 /// Returns the yield count for `ctx`
 [[gnu::hot]]
 const uint64_t &

ircd/ctx.h

@@ -52,6 +52,8 @@ struct ircd::ctx::ctx
 	uint64_t id {++id_ctr};                      // Unique runtime ID
 	string_view name;                            // User given name (optional)
 	context::flags flags;                        // User given flags
+	int8_t nice {0};                             // Scheduling priority nice-value
+	int8_t ionice {0};                           // IO priority nice-value (defaults for fs::opts)
 	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::deadline_timer alarm;           // acting semaphore (64B)

ircd/db_env.cc

@@ -3987,6 +3987,8 @@ ircd::db::database::env::state::pool::pool(database &d,
 {
 	pri == Priority::HIGH?
 		IOPriority::IO_HIGH:
+	pri == Priority::BOTTOM?
+		IOPriority::IO_LOW:
 		IOPriority::IO_LOW
 }
 ,name
@@ -4002,6 +4004,10 @@ ircd::db::database::env::state::pool::pool(database &d,
 	0,                     // initial workers
 	-1,                    // queue hard limit
 	-1,                    // queue soft limit
+	true,                  // queue_max_blocking
+	true,                  // queue_max_dwarning
+	make_nice(iopri),      // ionice
+	make_nice(this->pri),  // nice
 }
 ,p
 {