glibc/use_madv_free.patch

--- glibc-2.24/malloc/malloc.c~	2016-08-27 04:16:33.000000000 +0000
+++ glibc-2.24/malloc/malloc.c	2016-11-13 22:53:14.772986778 +0000
@@ -4568,7 +4568,7 @@
                        content.  */
                     memset (paligned_mem, 0x89, size & ~psm1);
 #endif
-                    __madvise (paligned_mem, size & ~psm1, MADV_DONTNEED);
+                    __madvise (paligned_mem, size & ~psm1, MADV_FREE);
 
                     result = 1;
                   }
--- glibc-2.24/malloc/arena.c~	2016-08-02 02:01:36.000000000 +0000
+++ glibc-2.24/malloc/arena.c	2016-11-13 22:52:52.889299846 +0000
@@ -524,7 +524,7 @@
       h->mprotect_size = new_size;
     }
   else
-    __madvise ((char *) h + new_size, diff, MADV_DONTNEED);
+    __madvise ((char *) h + new_size, diff, MADV_FREE);
   /*fprintf(stderr, "shrink %p %08lx\n", h, new_size);*/
 
   h->size = new_size;