From 061a0ea6dd3edd1b68158affebc7f8fc2183dbbc Mon Sep 17 00:00:00 2001
From: David Finkel <davidf@vimeo.com>
Date: Mon, 9 Dec 2019 16:16:43 -0500
Subject: [PATCH] CacheType: convert to uint8

We only need ~2 bits for the types of cache. `int` is 64-bits on 64-bit
platforms, which is significant overkill.

Convert CacheType to a uint8 and move it to the end of the `cache`
struct so it only affects alignment, but not the actual size. (we can
pack in other small values at the end later as well)
---
 cachetype_string.go | 2 +-
 galaxycache.go      | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/cachetype_string.go b/cachetype_string.go
index 7a93c371..abc5c2ee 100644
--- a/cachetype_string.go
+++ b/cachetype_string.go
@@ -19,7 +19,7 @@ var _CacheType_index = [...]uint8{0, 9, 17, 31}
 
 func (i CacheType) String() string {
 	i -= 1
-	if i < 0 || i >= CacheType(len(_CacheType_index)-1) {
+	if i >= CacheType(len(_CacheType_index)-1) {
 		return "CacheType(" + strconv.FormatInt(int64(i+1), 10) + ")"
 	}
 	return _CacheType_name[_CacheType_index[i]:_CacheType_index[i+1]]
diff --git a/galaxycache.go b/galaxycache.go
index 3211a453..a0171146 100644
--- a/galaxycache.go
+++ b/galaxycache.go
@@ -592,7 +592,7 @@ func (g *Galaxy) populateCache(ctx context.Context, key string, value *valWithSt
 }
 
 // CacheType represents a type of cache.
-type CacheType int
+type CacheType uint8
 
 const (
 	// MainCache is the cache for items that this peer is the
@@ -627,12 +627,12 @@ func (g *Galaxy) CacheStats(which CacheType) CacheStats {
 // and counts the size of all keys and values. Candidate cache only
 // utilizes the lru.Cache and mutex, not the included stats.
 type cache struct {
-	ctype      CacheType
 	mu         sync.Mutex
 	nbytes     int64 // of all keys and values
 	lru        *lru.Cache
 	nhit, nget int64
 	nevict     int64 // number of evictions
+	ctype      CacheType
 }
 
 func (c *cache) stats() CacheStats {