diff --git a/configure.ac b/configure.ac
index 1eb054d98c..c2bed71761 100644
--- a/configure.ac
+++ b/configure.ac
@@ -220,6 +220,13 @@
             #include <sys/random.h> 
             ])
 
+    AC_CHECK_HEADERS([malloc.h])
+    AC_CHECK_DECL([malloc_trim],
+        AC_DEFINE([HAVE_MALLOC_TRIM], [1], [Use malloc_trim]),
+        [], [
+            #include <malloc.h> 
+            ])
+
     OCFLAGS=$CFLAGS
     CFLAGS=""
     AC_CHECK_FUNCS([strlcpy strlcat])
diff --git a/src/detect-engine.c b/src/detect-engine.c
index 0fc2df6869..25e76445ed 100644
--- a/src/detect-engine.c
+++ b/src/detect-engine.c
@@ -4797,6 +4797,15 @@ int DetectEngineReload(const SCInstance *suri)
     SCLogDebug("old_de_ctx should have been freed");
 
     SCLogNotice("rule reload complete");
+
+#ifdef HAVE_MALLOC_TRIM
+    /* The reload process potentially frees up large amounts of memory.
+     * Encourage the memory management system to reclaim as much as it
+     * can.
+     */
+    malloc_trim(0);
+#endif
+
     return 0;
 }
 
diff --git a/src/suricata-common.h b/src/suricata-common.h
index 4aad25a252..297a6fc452 100644
--- a/src/suricata-common.h
+++ b/src/suricata-common.h
@@ -212,6 +212,10 @@ typedef unsigned char u_char;
 #include <netdb.h>
 #endif
 
+#if HAVE_MALLOC_H
+#include <malloc.h>
+#endif
+
 #if __CYGWIN__
 #if !defined _X86_ && !defined __x86_64
 #define _X86_