From d15385dab87b0142ff5b517dc9ff7223c86ee812 Mon Sep 17 00:00:00 2001
From: Brian Goff <cpuguy83@gmail.com>
Date: Tue, 13 Mar 2018 11:58:05 -0400
Subject: [PATCH 1/2] Add `Len()` to image store for info endpoint

In info, we only need the number of images, but `CountImages` was
getting the whole map of images and then grabbing the length from that.
This causes a lot of unnecessary CPU usage and memory allocations, which
increases with O(n) on the number of images.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Upstream-commit: f6a7763b6f3256bed9a7352021745189d0ca8dc9
Component: engine
---
 components/engine/daemon/images/service.go | 2 +-
 components/engine/image/store.go           | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/components/engine/daemon/images/service.go b/components/engine/daemon/images/service.go
index 70a8bf4455..4af48959bf 100644
--- a/components/engine/daemon/images/service.go
+++ b/components/engine/daemon/images/service.go
@@ -77,7 +77,7 @@ type ImageService struct {
 // CountImages returns the number of images stored by ImageService
 // called from info.go
 func (i *ImageService) CountImages() int {
-	return len(i.imageStore.Map())
+	return i.imageStore.Len()
 }
 
 // Children returns the children image.IDs for a parent image.
diff --git a/components/engine/image/store.go b/components/engine/image/store.go
index a8f8cee5b2..9fd7d7dcf3 100644
--- a/components/engine/image/store.go
+++ b/components/engine/image/store.go
@@ -27,6 +27,7 @@ type Store interface {
 	Children(id ID) []ID
 	Map() map[ID]*Image
 	Heads() map[ID]*Image
+	Len() int
 }
 
 // LayerGetReleaser is a minimal interface for getting and releasing images.
@@ -336,3 +337,9 @@ func (is *store) imagesMap(all bool) map[ID]*Image {
 	}
 	return images
 }
+
+func (is *store) Len() int {
+	is.RLock()
+	defer is.RUnlock()
+	return len(is.images)
+}

From 2c6fe9c5245715ccbb0ee17388cb88b4995a9044 Mon Sep 17 00:00:00 2001
From: Brian Goff <cpuguy83@gmail.com>
Date: Tue, 13 Mar 2018 12:21:56 -0400
Subject: [PATCH 2/2] Change containerd monitor ticker to sleep

With the ticker this could end up just doing back-to-back checks, which
isn't really what we want here.
Instead use a sleep to ensure we actually sleep for the desired
interval.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Upstream-commit: 04a0d6b863ed50cfffa79936cf9cdab7a3a9e7df
Component: engine
---
 components/engine/image/store_test.go            | 15 +++++++++++++++
 components/engine/libcontainerd/remote_daemon.go | 12 ++++++++----
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/components/engine/image/store_test.go b/components/engine/image/store_test.go
index ff40f7ea22..b1300657a0 100644
--- a/components/engine/image/store_test.go
+++ b/components/engine/image/store_test.go
@@ -1,6 +1,7 @@
 package image // import "github.com/docker/docker/image"
 
 import (
+	"fmt"
 	"runtime"
 	"testing"
 
@@ -171,6 +172,20 @@ func TestGetAndSetLastUpdated(t *testing.T) {
 	assert.Equal(t, updated.IsZero(), false)
 }
 
+func TestStoreLen(t *testing.T) {
+	store, cleanup := defaultImageStore(t)
+	defer cleanup()
+
+	expected := 10
+	for i := 0; i < expected; i++ {
+		_, err := store.Create([]byte(fmt.Sprintf(`{"comment": "abc%d", "rootfs": {"type": "layers"}}`, i)))
+		assert.NoError(t, err)
+	}
+	numImages := store.Len()
+	assert.Equal(t, expected, numImages)
+	assert.Equal(t, len(store.Map()), numImages)
+}
+
 type mockLayerGetReleaser struct{}
 
 func (ls *mockLayerGetReleaser) Get(layer.ChainID) (layer.Layer, error) {
diff --git a/components/engine/libcontainerd/remote_daemon.go b/components/engine/libcontainerd/remote_daemon.go
index fb3e0bdda8..35ccc0e4a9 100644
--- a/components/engine/libcontainerd/remote_daemon.go
+++ b/components/engine/libcontainerd/remote_daemon.go
@@ -263,11 +263,15 @@ func (r *remote) startContainerd() error {
 func (r *remote) monitorConnection(monitor *containerd.Client) {
 	var transientFailureCount = 0
 
-	ticker := time.NewTicker(500 * time.Millisecond)
-	defer ticker.Stop()
-
 	for {
-		<-ticker.C
+		select {
+		case <-r.shutdownContext.Done():
+			r.logger.Info("stopping healthcheck following graceful shutdown")
+			monitor.Close()
+			return
+		case <-time.After(500 * time.Millisecond):
+		}
+
 		ctx, cancel := context.WithTimeout(r.shutdownContext, healthCheckTimeout)
 		_, err := monitor.IsServing(ctx)
 		cancel()