From 348f9fa557ebcbf86fa8d0058e78bf2f12aa925a Mon Sep 17 00:00:00 2001
From: Daniel Micay <danielmicay@gmail.com>
Date: Sat, 6 Oct 2018 15:36:03 -0400
Subject: [PATCH] add configuration for frequency of guard slabs

---
 config.h | 2 +-
 malloc.c | 5 ++++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/config.h b/config.h
index 37d8633..bd6aa0e 100644
--- a/config.h
+++ b/config.h
@@ -3,11 +3,11 @@
 
 #include <stdbool.h>
 
-#define GUARD_SLABS true
 #define WRITE_AFTER_FREE_CHECK true
 #define SLOT_RANDOMIZE true
 #define ZERO_ON_FREE true
 #define SLAB_CANARY true
+#define GUARD_SLABS_INTERVAL 1
 #define GUARD_SIZE_DIVISOR 2
 
 #endif
diff --git a/malloc.c b/malloc.c
index 090ddd4..2fd9aa8 100644
--- a/malloc.c
+++ b/malloc.c
@@ -141,6 +141,7 @@ static struct size_class {
     struct random_state rng;
     size_t metadata_allocated;
     size_t metadata_count;
+    size_t metadata_count_unguarded;
 } __attribute__((aligned(CACHELINE_SIZE))) size_class_metadata[N_SIZE_CLASSES];
 
 static const size_t class_region_size = 128ULL * 1024 * 1024 * 1024;
@@ -180,8 +181,10 @@ static struct slab_metadata *alloc_metadata(struct size_class *c, size_t slab_si
         return NULL;
     }
     c->metadata_count++;
-    if (GUARD_SLABS) {
+    c->metadata_count_unguarded++;
+    if (c->metadata_count_unguarded >= GUARD_SLABS_INTERVAL) {
         c->metadata_count++;
+        c->metadata_count_unguarded = 0;
     }
     return metadata;
 }