cmd, core, eth, miner, params: configurable gas floor and ceil

miner/worker.go

@@ -127,6 +127,9 @@ type worker struct {
 	eth    Backend
 	chain  *core.BlockChain
 
+	gasFloor uint64
+	gasCeil  uint64
+
 	// Subscriptions
 	mux          *event.TypeMux
 	txsCh        chan core.NewTxsEvent
@@ -171,13 +174,15 @@ type worker struct {
 	resubmitHook func(time.Duration, time.Duration) // Method to call upon updating resubmitting interval.
 }
 
-func newWorker(config *params.ChainConfig, engine consensus.Engine, eth Backend, mux *event.TypeMux, recommit time.Duration) *worker {
+func newWorker(config *params.ChainConfig, engine consensus.Engine, eth Backend, mux *event.TypeMux, recommit time.Duration, gasFloor, gasCeil uint64) *worker {
 	worker := &worker{
 		config:             config,
 		engine:             engine,
 		eth:                eth,
 		mux:                mux,
 		chain:              eth.BlockChain(),
+		gasFloor:           gasFloor,
+		gasCeil:            gasCeil,
 		possibleUncles:     make(map[common.Hash]*types.Block),
 		unconfirmed:        newUnconfirmedBlocks(eth.BlockChain(), miningLogAtDepth),
 		pendingTasks:       make(map[common.Hash]*task),
@@ -807,7 +812,7 @@ func (w *worker) commitNewWork(interrupt *int32, noempty bool) {
 	header := &types.Header{
 		ParentHash: parent.Hash(),
 		Number:     num.Add(num, common.Big1),
-		GasLimit:   core.CalcGasLimit(parent),
+		GasLimit:   core.CalcGasLimit(parent, w.gasFloor, w.gasCeil),
 		Extra:      w.extra,
 		Time:       big.NewInt(tstamp),
 	}