implement a worker to consolidate HasBlock provide calls into one to alieviate memory pressure

exchange/bitswap/bitswap.go

@@ -89,6 +89,7 @@ func New(parent context.Context, p peer.ID, network bsnet.BitSwapNetwork,
 		batchRequests: make(chan *blockRequest, sizeBatchRequestChan),
 		process:       px,
 		newBlocks:     make(chan *blocks.Block, HasBlockBufferSize),
+		provideKeys:   make(chan u.Key),
 	}
 	network.SetDelegate(bs)
 
@@ -124,6 +125,8 @@ type Bitswap struct {
 	process process.Process
 
 	newBlocks chan *blocks.Block
+
+	provideKeys chan u.Key
 }
 
 type blockRequest struct {

exchange/bitswap/workers.go

@@ -6,6 +6,7 @@ import (
 	inflect "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/chuckpreslar/inflect"
 	process "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/goprocess"
 	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
+	u "github.com/jbenet/go-ipfs/util"
 )
 
 func (bs *Bitswap) startWorkers(px process.Process, ctx context.Context) {
@@ -24,6 +25,10 @@ func (bs *Bitswap) startWorkers(px process.Process, ctx context.Context) {
 		bs.rebroadcastWorker(ctx)
 	})
 
+	px.Go(func(px process.Process) {
+		bs.provideCollector(ctx)
+	})
+
 	// Spawn up multiple workers to handle incoming blocks
 	// consider increasing number if providing blocks bottlenecks
 	// file transfers
@@ -56,6 +61,40 @@ func (bs *Bitswap) taskWorker(ctx context.Context) {
 }
 
 func (bs *Bitswap) provideWorker(ctx context.Context) {
+	for {
+		select {
+		case k, ok := <-bs.provideKeys:
+			if !ok {
+				log.Debug("provideKeys channel closed")
+				return
+			}
+			ctx, _ := context.WithTimeout(ctx, provideTimeout)
+			err := bs.network.Provide(ctx, k)
+			if err != nil {
+				log.Error(err)
+			}
+		case <-ctx.Done():
+			return
+		}
+	}
+}
+
+func (bs *Bitswap) provideCollector(ctx context.Context) {
+	defer close(bs.provideKeys)
+	var toprovide []u.Key
+	var nextKey u.Key
+
+	select {
+	case blk, ok := <-bs.newBlocks:
+		if !ok {
+			log.Debug("newBlocks channel closed")
+			return
+		}
+		nextKey = blk.Key()
+	case <-ctx.Done():
+		return
+	}
+
 	for {
 		select {
 		case blk, ok := <-bs.newBlocks:
@@ -63,10 +102,21 @@ func (bs *Bitswap) provideWorker(ctx context.Context) {
 				log.Debug("newBlocks channel closed")
 				return
 			}
-			ctx, _ := context.WithTimeout(ctx, provideTimeout)
-			err := bs.network.Provide(ctx, blk.Key())
-			if err != nil {
-				log.Error(err)
+			toprovide = append(toprovide, blk.Key())
+		case bs.provideKeys <- nextKey:
+			if len(toprovide) > 0 {
+				nextKey = toprovide[0]
+				toprovide = toprovide[1:]
+			} else {
+				select {
+				case blk, ok := <-bs.newBlocks:
+					if !ok {
+						return
+					}
+					nextKey = blk.Key()
+				case <-ctx.Done():
+					return
+				}
 			}
 		case <-ctx.Done():
 			return