diff --git a/llama-util.h b/llama-util.h
index 351ee611a..43b6f05ad 100644
--- a/llama-util.h
+++ b/llama-util.h
@@ -175,7 +175,7 @@ struct llama_mmap {
     llama_mmap(struct llama_file * file, size_t prefetch = (size_t) -1 /* -1 = max value */, bool numa = false) {
         size = file->size;
         int fd = fileno(file->fp);
-        int flags = MAP_SHARED;
+        int flags = MAP_PRIVATE;
         // prefetch/readahead impairs performance on NUMA systems
         if (numa) { prefetch = 0; }
 #ifdef __linux__