--- a/src/hotspot/os/aix/os_aix.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/aix/os_aix.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -3733,8 +3733,7 @@
 
   /* Scan the directory */
   bool result = true;
-  char buf[sizeof(struct dirent) + MAX_PATH];
-  while (result && (ptr = ::readdir(dir)) != NULL) {
+  while (result && (ptr = readdir(dir)) != NULL) {
     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
       result = false;
     }

--- a/src/hotspot/os/aix/os_aix.inline.hpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/aix/os_aix.inline.hpp	Tue Jul 17 15:59:47 2018 -0400
@@ -74,17 +74,6 @@
 
 inline const int os::default_file_open_flags() { return 0;}
 
-inline DIR* os::opendir(const char* dirname) {
-  assert(dirname != NULL, "just checking");
-  return ::opendir(dirname);
-}
-
-inline int os::readdir_buf_size(const char *path) {
-  // According to aix sys/limits, NAME_MAX must be retrieved at runtime.
-  const long my_NAME_MAX = pathconf(path, _PC_NAME_MAX);
-  return my_NAME_MAX + sizeof(dirent) + 1;
-}
-
 inline jlong os::lseek(int fd, jlong offset, int whence) {
   return (jlong) ::lseek64(fd, offset, whence);
 }
@@ -97,23 +86,6 @@
   return ::ftruncate64(fd, length);
 }
 
-inline struct dirent* os::readdir(DIR* dirp, dirent *dbuf) {
-  dirent* p = NULL;
-  assert(dirp != NULL, "just checking");
-
-  // AIX: slightly different from POSIX.
-  // On AIX, readdir_r returns 0 or != 0 and error details in errno.
-  if (::readdir_r(dirp, dbuf, &p) != 0) {
-    return NULL;
-  }
-  return p;
-}
-
-inline int os::closedir(DIR *dirp) {
-  assert(dirp != NULL, "argument is NULL");
-  return ::closedir(dirp);
-}
-
 // macros for restartable system calls
 
 #define RESTARTABLE(_cmd, _result) do { \

--- a/src/hotspot/os/aix/os_perf_aix.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/aix/os_perf_aix.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -893,21 +893,14 @@
 }
 
 int SystemProcessInterface::SystemProcesses::ProcessIterator::next_process() {
-  struct dirent* entry;
-
   if (!is_valid()) {
     return OS_ERR;
   }
 
   do {
-      entry = os::readdir(_dir, _entry);
-    if (entry == NULL) {
-      // error
-      _valid = false;
-      return OS_ERR;
-    }
+    _entry = os::readdir(_dir);
     if (_entry == NULL) {
-      // reached end
+      // Error or reached end.  Could use errno to distinguish those cases.
       _valid = false;
       return OS_ERR;
     }
@@ -929,11 +922,8 @@
 }
 
 SystemProcessInterface::SystemProcesses::ProcessIterator::~ProcessIterator() {
-  if (_entry != NULL) {
-    FREE_C_HEAP_ARRAY(char, _entry);
-  }
   if (_dir != NULL) {
-    closedir(_dir);
+    os::closedir(_dir);
   }
 }
 

--- a/src/hotspot/os/aix/perfMemory_aix.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/aix/perfMemory_aix.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -617,9 +617,8 @@
   // 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) {
@@ -653,9 +652,8 @@
     }
 
     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;
@@ -699,11 +697,9 @@
       }
     }
     os::closedir(subdirp);
-    FREE_C_HEAP_ARRAY(char, udbuf);
     FREE_C_HEAP_ARRAY(char, usrdir_name);
   }
   os::closedir(tmpdirp);
-  FREE_C_HEAP_ARRAY(char, tdbuf);
 
   return(oldest_user);
 }
@@ -779,10 +775,8 @@
   // 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);
 
@@ -820,8 +814,6 @@
 
   // Close the directory and reset the current working directory.
   close_directory_secure_cwd(dirp, saved_cwd_fd);
-
-  FREE_C_HEAP_ARRAY(char, dbuf);
 }
 
 // Make the user specific temporary directory. Returns true if

--- a/src/hotspot/os/bsd/os_bsd.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/bsd/os_bsd.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -3506,8 +3506,7 @@
 
   // Scan the directory
   bool result = true;
-  char buf[sizeof(struct dirent) + MAX_PATH];
-  while (result && (ptr = ::readdir(dir)) != NULL) {
+  while (result && (ptr = readdir(dir)) != NULL) {
     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
       result = false;
     }

--- a/src/hotspot/os/bsd/os_bsd.inline.hpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/bsd/os_bsd.inline.hpp	Tue Jul 17 15:59:47 2018 -0400
@@ -77,17 +77,6 @@
 
 inline const int os::default_file_open_flags() { return 0;}
 
-inline DIR* os::opendir(const char* dirname)
-{
-  assert(dirname != NULL, "just checking");
-  return ::opendir(dirname);
-}
-
-inline int os::readdir_buf_size(const char *path)
-{
-  return NAME_MAX + sizeof(dirent) + 1;
-}
-
 inline jlong os::lseek(int fd, jlong offset, int whence) {
   return (jlong) ::lseek(fd, offset, whence);
 }
@@ -100,28 +89,6 @@
   return ::ftruncate(fd, length);
 }
 
-inline struct dirent* os::readdir(DIR* dirp, dirent *dbuf)
-{
-  dirent* p;
-  int status;
-  assert(dirp != NULL, "just checking");
-
-  // NOTE: Bsd readdir_r (on RH 6.2 and 7.2 at least) is NOT like the POSIX
-  // version. Here is the doc for this function:
-  // http://www.gnu.org/manual/glibc-2.2.3/html_node/libc_262.html
-
-  if((status = ::readdir_r(dirp, dbuf, &p)) != 0) {
-    errno = status;
-    return NULL;
-  } else
-    return p;
-}
-
-inline int os::closedir(DIR *dirp) {
-  assert(dirp != NULL, "argument is NULL");
-  return ::closedir(dirp);
-}
-
 // macros for restartable system calls
 
 #define RESTARTABLE(_cmd, _result) do { \

--- a/src/hotspot/os/bsd/perfMemory_bsd.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/bsd/perfMemory_bsd.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -535,9 +535,8 @@
   // 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) {
@@ -559,9 +558,8 @@
     }
 
     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;
@@ -605,11 +603,9 @@
       }
     }
     os::closedir(subdirp);
-    FREE_C_HEAP_ARRAY(char, udbuf);
     FREE_C_HEAP_ARRAY(char, usrdir_name);
   }
   os::closedir(tmpdirp);
-  FREE_C_HEAP_ARRAY(char, tdbuf);
 
   return(oldest_user);
 }
@@ -688,10 +684,8 @@
   // 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);
 
@@ -730,8 +724,6 @@
 
   // close the directory and reset the current working directory
   close_directory_secure_cwd(dirp, saved_cwd_fd);
-
-  FREE_C_HEAP_ARRAY(char, dbuf);
 }
 
 // make the user specific temporary directory. Returns true if

--- a/src/hotspot/os/linux/os_linux.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/linux/os_linux.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -5375,8 +5375,7 @@
 
   // Scan the directory
   bool result = true;
-  char buf[sizeof(struct dirent) + MAX_PATH];
-  while (result && (ptr = ::readdir(dir)) != NULL) {
+  while (result && (ptr = readdir(dir)) != NULL) {
     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
       result = false;
     }

--- a/src/hotspot/os/linux/os_linux.inline.hpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/linux/os_linux.inline.hpp	Tue Jul 17 15:59:47 2018 -0400
@@ -69,17 +69,6 @@
 
 inline const int os::default_file_open_flags() { return 0;}
 
-inline DIR* os::opendir(const char* dirname)
-{
-  assert(dirname != NULL, "just checking");
-  return ::opendir(dirname);
-}
-
-inline int os::readdir_buf_size(const char *path)
-{
-  return NAME_MAX + sizeof(dirent) + 1;
-}
-
 inline jlong os::lseek(int fd, jlong offset, int whence) {
   return (jlong) ::lseek64(fd, offset, whence);
 }
@@ -92,17 +81,6 @@
   return ::ftruncate64(fd, length);
 }
 
-inline struct dirent* os::readdir(DIR* dirp, dirent *dbuf)
-{
-  assert(dirp != NULL, "just checking");
-  return ::readdir(dirp);
-}
-
-inline int os::closedir(DIR *dirp) {
-  assert(dirp != NULL, "argument is NULL");
-  return ::closedir(dirp);
-}
-
 // macros for restartable system calls
 
 #define RESTARTABLE(_cmd, _result) do { \

--- a/src/hotspot/os/linux/os_perf_linux.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/linux/os_perf_linux.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -895,21 +895,14 @@
 }
 
 int SystemProcessInterface::SystemProcesses::ProcessIterator::next_process() {
-  struct dirent* entry;
-
   if (!is_valid()) {
     return OS_ERR;
   }
 
   do {
-      entry = os::readdir(_dir, _entry);
-    if (entry == NULL) {
-      // error
-      _valid = false;
-      return OS_ERR;
-    }
+    _entry = os::readdir(_dir);
     if (_entry == NULL) {
-      // reached end
+      // Error or reached end.  Could use errno to distinguish those cases.
       _valid = false;
       return OS_ERR;
     }
@@ -926,11 +919,8 @@
 }
 
 bool SystemProcessInterface::SystemProcesses::ProcessIterator::initialize() {
-  _dir = opendir("/proc");
-  _entry = (struct dirent*)NEW_C_HEAP_ARRAY(char, sizeof(struct dirent) + NAME_MAX + 1, mtInternal);
-  if (NULL == _entry) {
-    return false;
-  }
+  _dir = os::opendir("/proc");
+  _entry = NULL;
   _valid = true;
   next_process();
 
@@ -938,11 +928,8 @@
 }
 
 SystemProcessInterface::SystemProcesses::ProcessIterator::~ProcessIterator() {
-  if (_entry != NULL) {
-    FREE_C_HEAP_ARRAY(char, _entry);
-  }
   if (_dir != NULL) {
-    closedir(_dir);
+    os::closedir(_dir);
   }
 }
 

--- a/src/hotspot/os/linux/perfMemory_linux.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/linux/perfMemory_linux.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -561,9 +561,8 @@
   // 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) {
@@ -597,9 +596,8 @@
     }
 
     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) == searchpid) {
         struct stat statbuf;
@@ -643,11 +641,9 @@
       }
     }
     os::closedir(subdirp);
-    FREE_C_HEAP_ARRAY(char, udbuf);
     FREE_C_HEAP_ARRAY(char, usrdir_name);
   }
   os::closedir(tmpdirp);
-  FREE_C_HEAP_ARRAY(char, tdbuf);
 
   return(oldest_user);
 }
@@ -769,10 +765,8 @@
   // 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);
 
@@ -809,8 +803,6 @@
 
   // close the directory and reset the current working directory
   close_directory_secure_cwd(dirp, saved_cwd_fd);
-
-  FREE_C_HEAP_ARRAY(char, dbuf);
 }
 
 // make the user specific temporary directory. Returns true if

--- a/src/hotspot/os/posix/os_posix.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/posix/os_posix.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -35,6 +35,7 @@
 #include "utilities/macros.hpp"
 #include "utilities/vmError.hpp"
 
+#include <dirent.h>
 #include <dlfcn.h>
 #include <pthread.h>
 #include <signal.h>
@@ -527,6 +528,21 @@
   ::funlockfile(fp);
 }
 
+DIR* os::opendir(const char* dirname) {
+  assert(dirname != NULL, "just checking");
+  return ::opendir(dirname);
+}
+
+struct dirent* os::readdir(DIR* dirp) {
+  assert(dirp != NULL, "just checking");
+  return ::readdir(dirp);
+}
+
+int os::closedir(DIR *dirp) {
+  assert(dirp != NULL, "just checking");
+  return ::closedir(dirp);
+}
+
 // Builds a platform dependent Agent_OnLoad_<lib_name> function name
 // which is used to find statically linked in agents.
 // Parameters:

--- a/src/hotspot/os/solaris/os_perf_solaris.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/solaris/os_perf_solaris.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -604,15 +604,14 @@
 }
 
 int SystemProcessInterface::SystemProcesses::ProcessIterator::next_process() {
-  struct dirent* entry;
-
   if (!is_valid()) {
     return OS_ERR;
   }
 
   do {
-    if ((entry = os::readdir(_dir, _entry)) == NULL) {
-      // error
+    _entry = os::readdir(_dir);
+    if (_entry == NULL) {
+      // Error or reached end.  Could use errno to distinguish those cases.
       _valid = false;
       return OS_ERR;
     }
@@ -629,11 +628,8 @@
 }
 
 bool SystemProcessInterface::SystemProcesses::ProcessIterator::initialize() {
-  _dir = opendir("/proc");
-  _entry = (struct dirent*)NEW_C_HEAP_ARRAY(char, sizeof(struct dirent) + _PC_NAME_MAX + 1, mtInternal);
-  if (NULL == _entry) {
-    return false;
-  }
+  _dir = os::opendir("/proc");
+  _entry = NULL;
   _valid = true;
   next_process();
 
@@ -641,12 +637,8 @@
 }
 
 SystemProcessInterface::SystemProcesses::ProcessIterator::~ProcessIterator() {
-  if (_entry != NULL) {
-    FREE_C_HEAP_ARRAY(char, _entry);
-  }
-
   if (_dir != NULL) {
-    closedir(_dir);
+    os::closedir(_dir);
   }
 }
 

--- a/src/hotspot/os/solaris/os_solaris.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/solaris/os_solaris.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -4308,9 +4308,7 @@
 
   // Scan the directory
   bool result = true;
-  char buf[sizeof(struct dirent) + MAX_PATH];
-  struct dirent *dbuf = (struct dirent *) buf;
-  while (result && (ptr = readdir(dir, dbuf)) != NULL) {
+  while (result && (ptr = readdir(dir)) != NULL) {
     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
       result = false;
     }

--- a/src/hotspot/os/solaris/os_solaris.inline.hpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/solaris/os_solaris.inline.hpp	Tue Jul 17 15:59:47 2018 -0400
@@ -68,34 +68,6 @@
 
 inline const int os::default_file_open_flags() { return 0;}
 
-inline DIR* os::opendir(const char* dirname) {
-  assert(dirname != NULL, "just checking");
-  return ::opendir(dirname);
-}
-
-inline int os::readdir_buf_size(const char *path) {
-  int size = pathconf(path, _PC_NAME_MAX);
-  return (size < 0 ? MAXPATHLEN : size) + sizeof(dirent) + 1;
-}
-
-inline struct dirent* os::readdir(DIR* dirp, dirent* dbuf) {
-  assert(dirp != NULL, "just checking");
-  dirent* p;
-  int status;
-
-  if((status = ::readdir_r(dirp, dbuf, &p)) != 0) {
-    errno = status;
-    return NULL;
-  } else {
-    return p;
-  }
-}
-
-inline int os::closedir(DIR *dirp) {
-  assert(dirp != NULL, "argument is NULL");
-  return ::closedir(dirp);
-}
-
 //////////////////////////////////////////////////////////////////////////////
 ////////////////////////////////////////////////////////////////////////////////
 

--- a/src/hotspot/os/solaris/perfMemory_solaris.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/solaris/perfMemory_solaris.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -523,9 +523,8 @@
   // 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) {
@@ -559,9 +558,8 @@
     }
 
     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;
@@ -605,11 +603,9 @@
       }
     }
     os::closedir(subdirp);
-    FREE_C_HEAP_ARRAY(char, udbuf);
     FREE_C_HEAP_ARRAY(char, usrdir_name);
   }
   os::closedir(tmpdirp);
-  FREE_C_HEAP_ARRAY(char, tdbuf);
 
   return(oldest_user);
 }
@@ -736,10 +732,8 @@
   // 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);
 
@@ -778,8 +772,6 @@
 
   // close the directory and reset the current working directory
   close_directory_secure_cwd(dirp, saved_cwd_fd);
-
-  FREE_C_HEAP_ARRAY(char, dbuf);
 }
 
 // make the user specific temporary directory. Returns true if

--- a/src/hotspot/os/windows/os_windows.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/windows/os_windows.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -1170,11 +1170,10 @@
   return dirp;
 }
 
-// parameter dbuf unused on Windows
-struct dirent * os::readdir(DIR *dirp, dirent *dbuf) {
+struct dirent * os::readdir(DIR *dirp) {
   assert(dirp != NULL, "just checking");      // hotspot change
   if (dirp->handle == INVALID_HANDLE_VALUE) {
-    return 0;
+    return NULL;
   }
 
   strcpy(dirp->dirent.d_name, dirp->find_data.cFileName);
@@ -1182,7 +1181,7 @@
   if (!FindNextFile(dirp->handle, &dirp->find_data)) {
     if (GetLastError() == ERROR_INVALID_HANDLE) {
       errno = EBADF;
-      return 0;
+      return NULL;
     }
     FindClose(dirp->handle);
     dirp->handle = INVALID_HANDLE_VALUE;

--- a/src/hotspot/os/windows/os_windows.inline.hpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/windows/os_windows.inline.hpp	Tue Jul 17 15:59:47 2018 -0400
@@ -57,14 +57,6 @@
   return true;
 }
 
-inline int os::readdir_buf_size(const char *path)
-{
-  /* As Windows doesn't use the directory entry buffer passed to
-     os::readdir() this can be as short as possible */
-
-  return 1;
-}
-
 // Bang the shadow pages if they need to be touched to be mapped.
 inline void os::map_stack_shadow_pages(address sp) {
   // Write to each page of our new frame to force OS mapping.

--- a/src/hotspot/os/windows/perfMemory_windows.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/os/windows/perfMemory_windows.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -318,9 +318,8 @@
   // 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) {
@@ -353,9 +352,8 @@
     }
 
     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;
@@ -407,11 +405,9 @@
       }
     }
     os::closedir(subdirp);
-    FREE_C_HEAP_ARRAY(char, udbuf);
     FREE_C_HEAP_ARRAY(char, usrdir_name);
   }
   os::closedir(tmpdirp);
-  FREE_C_HEAP_ARRAY(char, tdbuf);
 
   return(latest_user);
 }
@@ -642,9 +638,8 @@
   // 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) {
 
     int pid = filename_to_pid(entry->d_name);
 
@@ -685,7 +680,6 @@
     errno = 0;
   }
   os::closedir(dirp);
-  FREE_C_HEAP_ARRAY(char, dbuf);
 }
 
 // create a file mapping object with the requested name, and size

--- a/src/hotspot/share/jfr/recorder/repository/jfrRepository.cpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/share/jfr/recorder/repository/jfrRepository.cpp	Tue Jul 17 15:59:47 2018 -0400
@@ -241,11 +241,7 @@
       return;
     }
     struct dirent* dentry;
-    char* dir_buffer = NEW_RESOURCE_ARRAY_RETURN_NULL(char, os::readdir_buf_size(_repo));
-    if (dir_buffer == NULL) {
-      return;
-    }
-    while ((dentry = os::readdir(dirp, (struct dirent*)dir_buffer)) != NULL) {
+    while ((dentry = os::readdir(dirp)) != NULL) {
       const char* const entry_path = filter(dentry->d_name);
       if (NULL != entry_path) {
         _files->append(entry_path);

--- a/src/hotspot/share/runtime/os.hpp	Tue Jul 17 12:03:10 2018 -0700
+++ b/src/hotspot/share/runtime/os.hpp	Tue Jul 17 15:59:47 2018 -0400
@@ -580,8 +580,7 @@
 
   // Reading directories.
   static DIR*           opendir(const char* dirname);
-  static int            readdir_buf_size(const char *path);
-  static struct dirent* readdir(DIR* dirp, dirent* dbuf);
+  static struct dirent* readdir(DIR* dirp);
   static int            closedir(DIR* dirp);
 
   // Dynamic library extension

--- a/test/jdk/ProblemList.txt	Tue Jul 17 12:03:10 2018 -0700
+++ b/test/jdk/ProblemList.txt	Tue Jul 17 15:59:47 2018 -0400
@@ -873,4 +873,3 @@
 
 jdk/jfr/event/io/TestInstrumentation.java                       8202142    generic-all
 jdk/jfr/event/sampling/TestNative.java                          8202142    generic-all
-jdk/jfr/event/os/TestSystemProcess.java                         8202835    linux-all