diff -r 5d306df084eb -r 0f2fe7d37d8c src/os/aix/vm/perfMemory_aix.cpp
--- a/src/os/aix/vm/perfMemory_aix.cpp	Tue Apr 30 14:49:19 2019 +0200
+++ b/src/os/aix/vm/perfMemory_aix.cpp	Mon Jun 17 16:41:38 2019 +0100
@@ -612,9 +612,8 @@
   // to determine the user name for the process id.
   //
   struct dirent* dentry;
-  char* tdbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(tmpdirname), mtInternal);
   errno = 0;
-  while ((dentry = os::readdir(tmpdirp, (struct dirent *)tdbuf)) != NULL) {
+  while ((dentry = os::readdir(tmpdirp)) != NULL) {
 
     // check if the directory entry is a hsperfdata file
     if (strncmp(dentry->d_name, PERFDATA_NAME, strlen(PERFDATA_NAME)) != 0) {
@@ -648,9 +647,8 @@
     }
 
     struct dirent* udentry;
-    char* udbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(usrdir_name), mtInternal);
     errno = 0;
-    while ((udentry = os::readdir(subdirp, (struct dirent *)udbuf)) != NULL) {
+    while ((udentry = os::readdir(subdirp)) != NULL) {
 
       if (filename_to_pid(udentry->d_name) == vmid) {
         struct stat statbuf;
@@ -694,11 +692,9 @@
       }
     }
     os::closedir(subdirp);
-    FREE_C_HEAP_ARRAY(char, udbuf, mtInternal);
     FREE_C_HEAP_ARRAY(char, usrdir_name, mtInternal);
   }
   os::closedir(tmpdirp);
-  FREE_C_HEAP_ARRAY(char, tdbuf, mtInternal);
 
   return(oldest_user);
 }
@@ -774,10 +770,8 @@
   // loop under these conditions is dependent upon the implementation of
   // opendir/readdir.
   struct dirent* entry;
-  char* dbuf = NEW_C_HEAP_ARRAY(char, os::readdir_buf_size(dirname), mtInternal);
-
   errno = 0;
-  while ((entry = os::readdir(dirp, (struct dirent *)dbuf)) != NULL) {
+  while ((entry = os::readdir(dirp)) != NULL) {
 
     pid_t pid = filename_to_pid(entry->d_name);
 
@@ -816,7 +810,6 @@
   // Close the directory and reset the current working directory.
   close_directory_secure_cwd(dirp, saved_cwd_fd);
 
-  FREE_C_HEAP_ARRAY(char, dbuf, mtInternal);
 }
 
 // Make the user specific temporary directory. Returns true if