Set auto-revert-use-notify to nil in global-auto-revert-mode. (Bug#22814)

* etc/NEWS:
* etc/PROBLEMS: Mention this.

* lisp/autorevert.el (global-auto-revert-mode): Set
`auto-revert-use-notify' to nil.  (Bug#22814)

etc/NEWS

@@ -1222,9 +1222,15 @@ make the new option `eshell-destroy-buffer-when-process-dies' non-nil.
 ** tar-mode: new `tar-new-entry' command, allowing for new members to
 be added to the archive.
 
+** Autorevert
+
 ---
-** Autorevert: dired buffers are also auto-reverted via file
-notifications, if Emacs is compiled with file notification support.
+*** Dired buffers are also auto-reverted via file notifications, if
+Emacs is compiled with file notification support.
+
+---
+*** `auto-revert-use-notify' is set to nil in `global-auto-revert-mode'.
+See <http://debbugs.gnu.org/22814>.
 
 ** File Notifications
 

etc/PROBLEMS

@@ -601,6 +601,7 @@ can cause this error.  Remove that file, execute 'ispell-kill-ispell'
 in Emacs, and then try spell-checking again.
 
 *** Emacs eats all file descriptors when using kqueue file notifications.
+See <http://debbugs.gnu.org/22814>.
 
 When you have a large number of buffers running auto-revert-mode, and
 Emacs is configured to use the kqueue file notification library, it
@@ -608,7 +609,7 @@ uses an own file descriptor for every watched file.  On systems with a
 small limit of file descriptors allowed per process, like OS X, you
 could run out of file descriptors.  You won't be able to open new files.
 
-Set auto-revert-use-notify to nil in order to avoid this problem.
+auto-revert-use-notify is set to nil in global-auto-revert-mode, therefore.
 
 * Runtime problems related to font handling
 

lisp/autorevert.el

@@ -458,7 +458,11 @@ specifies in the mode line."
   :global t :group 'auto-revert :lighter global-auto-revert-mode-text
   (auto-revert-set-timer)
   (if global-auto-revert-mode
-      (auto-revert-buffers)
+      (progn
+        ;; We disable file notification because it could use too many
+        ;; ressources.  See <http://debbugs.gnu.org/22814>.
+        (setq auto-revert-use-notify nil)
+        (auto-revert-buffers))
     (dolist (buf (buffer-list))
       (with-current-buffer buf
 	(when auto-revert-use-notify