go/src/runtime/coro.go

type coro …

// newcoro creates a new coro containing a
// goroutine blocked waiting to run f
// and returns that coro.
func newcoro(f func(*coro)) *coro { … }

// corostart is the entry func for a new coroutine.
// It runs the coroutine user function f passed to corostart
// and then calls coroexit to remove the extra concurrency.
func corostart() { … }

// coroexit is like coroswitch but closes the coro
// and exits the current goroutine
func coroexit(c *coro) { … }

// coroswitch switches to the goroutine blocked on c
// and then blocks the current goroutine on c.
func coroswitch(c *coro) { … }

// coroswitch_m is the implementation of coroswitch
// that runs on the m stack.
//
// Note: Coroutine switches are expected to happen at
// an order of magnitude (or more) higher frequency
// than regular goroutine switches, so this path is heavily
// optimized to remove unnecessary work.
// The fast path here is three CAS: the one at the top on gp.atomicstatus,
// the one in the middle to choose the next g,
// and the one at the bottom on gnext.atomicstatus.
// It is important not to add more atomic operations or other
// expensive operations to the fast path.
func coroswitch_m(gp *g) { … }