bug#17751: 24.4.50; More memory leaks under OS X Mavericks

[Steve Purcell]

Even with this recent nightly Emacs build from emacsformacosx.com, I've
been suffering from the distnoted memory/CPU-ballooning issue addressed in
#15946, with that process reaching > 100% CPU and several GB in
memory. Quitting Emacs solves the problem.

In the discussion on #15946, Jan D suggested running "leaks" on Emacs to
see what's going on, so I tried that:

Starting with an "emacs -Q", I can fire up the "leaks" command in a loop
and watch Emacs start to leak memory.

While Emacs is the front-most application and the mouse is moving above
it, new leaks appear. When the mouse stops, the leaks stop appearing.

While the cursor blinks (as it does, by default), new leaks appear. When
the cursor stops blinking after a few seconds, the leaks stop
appearing. (Unless the mouse is also moving.)

As I write this message in the clean "emacs -Q" instance, "leaks" tells
me:

   Process 60460: 53511 leaks for 11106784 total leaked bytes.

So 11MB leaked in the space of a few minutes and a few lines typed, with
just a couple of buffers open!

The leaks look like this:

  Leak: 0x10c1d62a0  size=160  zone: DefaultMallocZone_0x1006c5000   
OS_dispatch_source  ObjC  libdispatch.dylib
        0x762d8c20 0x00007fff 0x00000001 0x00000000      .-v............
        0x89abcdef 0xffffffff 0x762da480 0x00007fff     ..........-v....
        0x00000000 0x00000000 0x00000000 0x00000000     ................
        0x00000000 0x00000000 0x00000000 0x00000000     ................
        0x00000000 0x00000000 0x00000000 0x00000000     ................
        0x00000001 0x00000000 0x00009cc4 0x00000000     ................
        0x8979a90c 0x00007fff 0x014002f0 0x00000001     ..y.......@.....
        0x0c1d6390 0x00000001 0x00000002 0x0000004c     .c..........L...
        ...

Commenters in #15946 noted that they felt like application switching was
causing leaks, and what I'm seeing points to event handling or timer loops.

Any insights into what might be going on? This strikes me as a serious issue.



In GNU Emacs 24.4.50.1 (x86_64-apple-darwin, NS appkit-1038.36 Version 10.6.8 
(Build 10K549))
of 2014-06-04 on bob.porkrind.org
Repository revision: eliz@gnu.org-20140604075416-fzf3twev7l2gdfgm
Windowing system distributor `Apple', version 10.3.1265
Configured using:
`configure --host=x86_64-apple-darwin --build=i686-apple-darwin
--with-ns'

Configured features:
ACL LIBXML2 ZLIB

Important settings:
  value of $LC_CTYPE: en_US.UTF-8
  value of $LANG: en_US
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
s-x M-x r e p o <tab> <down> r t - e m a c s <tab> 
<return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
kill-region: The mark is not set now, so there is no region
Making completion list...
user-error: End of history; no default available

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message dired format-spec
rfc822 mml easymenu mml-sec mm-decode mm-bodies mm-encode mail-parse
rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045
ietf-drums mm-util help-fns mail-prsvr mail-utils time-date tooltip
electric uniquify ediff-hook vc-hooks lisp-float-type mwheel ns-win
tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment
lisp-mode prog-mode register page menu-bar rfn-eshadow timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham
georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese hebrew greek romanian slovak czech european ethiopic
indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple
abbrev minibuffer nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
cocoa ns multi-tty emacs)

Memory information:
((conses 16 80671 6737)
(symbols 48 18479 0)
(miscs 40 37 114)
(strings 32 12454 4751)
(string-bytes 1 326584)
(vectors 16 9358)
(vector-slots 8 370915 6294)
(floats 8 58 214)
(intervals 56 191 0)
(buffers 960 12))