From 1b56b88132166c2d92ab6e849c54e0ba2f2d5ab4 Mon Sep 17 00:00:00 2001
From: vyzo <vyzo@hackzen.org>
Date: Fri, 7 Aug 2020 19:50:10 +0300
Subject: [PATCH] add cooldown to message pruning

---
 chain/messagepool/config.go      |  4 +++
 chain/messagepool/messagepool.go | 47 +++++++++++++++++++-------------
 chain/messagepool/pruning.go     | 12 +++++++-
 chain/types/mpool.go             |  3 ++
 4 files changed, 46 insertions(+), 20 deletions(-)

diff --git a/chain/messagepool/config.go b/chain/messagepool/config.go
index a06a4a27d..a55fb649d 100644
--- a/chain/messagepool/config.go
+++ b/chain/messagepool/config.go
@@ -1,6 +1,8 @@
 package messagepool
 
 import (
+	"time"
+
 	"github.com/filecoin-project/lotus/chain/types"
 )
 
@@ -8,6 +10,7 @@ var (
 	ReplaceByFeeRatioDefault  = 1.25
 	MemPoolSizeLimitHiDefault = 30000
 	MemPoolSizeLimitLoDefault = 20000
+	PruneCooldownDefault      = time.Minute
 )
 
 func (mp *MessagePool) GetConfig() *types.MpoolConfig {
@@ -29,5 +32,6 @@ func DefaultConfig() *types.MpoolConfig {
 		SizeLimitHigh:     MemPoolSizeLimitHiDefault,
 		SizeLimitLow:      MemPoolSizeLimitLoDefault,
 		ReplaceByFeeRatio: ReplaceByFeeRatioDefault,
+		PruneCooldown:     PruneCooldownDefault,
 	}
 }
diff --git a/chain/messagepool/messagepool.go b/chain/messagepool/messagepool.go
index 56fa74f94..3ca1b3966 100644
--- a/chain/messagepool/messagepool.go
+++ b/chain/messagepool/messagepool.go
@@ -91,6 +91,9 @@ type MessagePool struct {
 	// pruneTrigger is a channel used to trigger a mempool pruning
 	pruneTrigger chan struct{}
 
+	// pruneCooldown is a channel used to allow a cooldown time between prunes
+	pruneCooldown chan struct{}
+
 	blsSigCache *lru.TwoQueueCache
 
 	changes *lps.PubSub
@@ -209,23 +212,27 @@ func New(api Provider, ds dtypes.MetadataDS, netName dtypes.NetworkName) (*Messa
 	cfg := DefaultConfig()
 
 	mp := &MessagePool{
-		closer:       make(chan struct{}),
-		repubTk:      build.Clock.Ticker(time.Duration(build.BlockDelaySecs) * 10 * time.Second),
-		localAddrs:   make(map[address.Address]struct{}),
-		pending:      make(map[address.Address]*msgSet),
-		minGasPrice:  types.NewInt(0),
-		pruneTrigger: make(chan struct{}, 1),
-		blsSigCache:  cache,
-		sigValCache:  verifcache,
-		changes:      lps.New(50),
-		localMsgs:    namespace.Wrap(ds, datastore.NewKey(localMsgsDs)),
-		api:          api,
-		netName:      netName,
-		cfg:          cfg,
-		rbfNum:       types.NewInt(uint64((cfg.ReplaceByFeeRatio - 1) * RbfDenom)),
-		rbfDenom:     types.NewInt(RbfDenom),
+		closer:        make(chan struct{}),
+		repubTk:       build.Clock.Ticker(time.Duration(build.BlockDelaySecs) * 10 * time.Second),
+		localAddrs:    make(map[address.Address]struct{}),
+		pending:       make(map[address.Address]*msgSet),
+		minGasPrice:   types.NewInt(0),
+		pruneTrigger:  make(chan struct{}, 1),
+		pruneCooldown: make(chan struct{}, 1),
+		blsSigCache:   cache,
+		sigValCache:   verifcache,
+		changes:       lps.New(50),
+		localMsgs:     namespace.Wrap(ds, datastore.NewKey(localMsgsDs)),
+		api:           api,
+		netName:       netName,
+		cfg:           cfg,
+		rbfNum:        types.NewInt(uint64((cfg.ReplaceByFeeRatio - 1) * RbfDenom)),
+		rbfDenom:      types.NewInt(RbfDenom),
 	}
 
+	// enable initial prunes
+	mp.pruneCooldown <- struct{}{}
+
 	if err := mp.loadLocal(); err != nil {
 		log.Errorf("loading local messages: %+v", err)
 	}
@@ -249,10 +256,12 @@ func (mp *MessagePool) Close() error {
 }
 
 func (mp *MessagePool) Prune() {
-	//so, its a single slot buffered channel. The first send fills the channel,
-	//the second send goes through when the pruning starts,
-	//and the third send goes through (and noops) after the pruning finishes
-	//and goes through the loop again
+	// this magic incantation of triggering prune thrice is here to make the Prune method
+	// synchronous:
+	// so, its a single slot buffered channel. The first send fills the channel,
+	// the second send goes through when the pruning starts,
+	// and the third send goes through (and noops) after the pruning finishes
+	// and goes through the loop again
 	mp.pruneTrigger <- struct{}{}
 	mp.pruneTrigger <- struct{}{}
 	mp.pruneTrigger <- struct{}{}
diff --git a/chain/messagepool/pruning.go b/chain/messagepool/pruning.go
index a39b7d266..143dd029e 100644
--- a/chain/messagepool/pruning.go
+++ b/chain/messagepool/pruning.go
@@ -23,7 +23,17 @@ func (mp *MessagePool) pruneExcessMessages() error {
 		return nil
 	}
 
-	return mp.pruneMessages(context.TODO(), ts)
+	select {
+	case <-mp.pruneCooldown:
+		err := mp.pruneMessages(context.TODO(), ts)
+		go func() {
+			time.Sleep(mp.cfg.PruneCooldown)
+			mp.pruneCooldown <- struct{}{}
+		}()
+		return err
+	default:
+		return xerrors.New("cannot prune before cooldown")
+	}
 }
 
 func (mp *MessagePool) pruneMessages(ctx context.Context, ts *types.TipSet) error {
diff --git a/chain/types/mpool.go b/chain/types/mpool.go
index a55a835ca..cd6a99a47 100644
--- a/chain/types/mpool.go
+++ b/chain/types/mpool.go
@@ -1,6 +1,8 @@
 package types
 
 import (
+	"time"
+
 	"github.com/filecoin-project/go-address"
 )
 
@@ -9,6 +11,7 @@ type MpoolConfig struct {
 	SizeLimitHigh     int
 	SizeLimitLow      int
 	ReplaceByFeeRatio float64
+	PruneCooldown     time.Duration
 }
 
 func (mc *MpoolConfig) Clone() *MpoolConfig {