From f441dfe2e33650f8741a156cfb5bc0275a4e4b5e Mon Sep 17 00:00:00 2001
From: Daniel Micay <danielmicay@gmail.com>
Date: Fri, 31 Aug 2018 23:10:26 -0400
Subject: [PATCH] align size class metadata to cacheline size

---
 malloc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/malloc.c b/malloc.c
index 33e574a..b997dbe 100644
--- a/malloc.c
+++ b/malloc.c
@@ -18,6 +18,7 @@
 
 static_assert(sizeof(void *) == 8, "64-bit only");
 
+#define CACHELINE_SIZE 64
 #define PAGE_SHIFT 12
 #define PAGE_SIZE ((size_t)1 << PAGE_SHIFT)
 #define PAGE_MASK ((size_t)(PAGE_SIZE - 1))
@@ -196,7 +197,7 @@ static struct size_class {
     struct random_state rng;
     size_t metadata_allocated;
     size_t metadata_count;
-} size_class_metadata[N_SIZE_CLASSES];
+} __attribute__((aligned(CACHELINE_SIZE))) size_class_metadata[N_SIZE_CLASSES];
 
 static const size_t class_region_size = 128ULL * 1024 * 1024 * 1024;
 static const size_t real_class_region_size = class_region_size * 2;