From ae1564df934f2c3b8213481f13ae0b9e6c4a9d2a Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@redhat.com>
Date: Wed, 9 Nov 2016 11:12:44 -0500
Subject: [PATCH] include/mempool: align shard_t to cacheline

Signed-off-by: Sage Weil <sage@redhat.com>
---
 src/include/mempool.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/include/mempool.h b/src/include/mempool.h
index e3733f8910a40..52bce73207795 100644
--- a/src/include/mempool.h
+++ b/src/include/mempool.h
@@ -31,6 +31,7 @@
 
 #include <common/Formatter.h>
 
+
 /*
 
 Memory Pools
@@ -167,10 +168,14 @@ enum {
   num_shards = 1 << num_shard_bits
 };
 
+// align shard to a cacheline
 struct shard_t {
   std::atomic<size_t> bytes = {0};
   std::atomic<size_t> items = {0};
-};
+  char __padding[128 - sizeof(std::atomic<size_t>)*2];
+} __attribute__ ((aligned (128)));
+
+static_assert(sizeof(shard_t) == 128, "shard_t should be cacheline-sized");
 
 struct stats_t {
   ssize_t items = 0;
-- 
2.39.5