pdWait  uintptr = 2
)

const pollBlockSize = 4 * 1024

// Network poller descriptor.
//
// No heap pointers.
type pollDesc struct {
	_     sys.NotInHeap
	link  *pollDesc      // in pollcache, protected by pollcache.lock
	fd    uintptr        // constant for pollDesc usage lifetime
	fdseq atomic.Uintptr // protects against stale pollDesc

	// atomicInfo holds bits from closing, rd, and wd,

NONE < defer;

# GC
NONE <
  sweepWaiters,
  assistQueue,
  sweep;

# Test only
NONE < testR, testW;

NONE < timerSend;

# Scheduler, timers, netpoll
NONE < allocmW, execW, cpuprof, pollCache, pollDesc, wakeableSleep;
scavenge, sweep, testR, wakeableSleep, timerSend < hchan;
assistQueue,
  cpuprof,
  forcegc,
  hchan,
  pollDesc, # pollDesc can interact with timers, which can lock sched.
  scavenge,

	lockRankTestW:           "testW",
	lockRankTimerSend:       "timerSend",
	lockRankAllocmW:         "allocmW",
	lockRankExecW:           "execW",
	lockRankCpuprof:         "cpuprof",
	lockRankPollCache:       "pollCache",
	lockRankPollDesc:        "pollDesc",
	lockRankWakeableSleep:   "wakeableSleep",
	lockRankHchan:           "hchan",
	lockRankAllocmR:         "allocmR",
	lockRankExecR:           "execR",