From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx136.postini.com [74.125.245.136]) by kanga.kvack.org (Postfix) with SMTP id CCE0D8D0003 for ; Mon, 14 Jan 2013 19:34:49 -0500 (EST) Message-ID: <1358210073.15692.60.camel@deadeye.wl.decadent.org.uk> Subject: Re: Bug#695182: [RFC] Reproducible OOM with just a few sleeps From: Ben Hutchings Date: Tue, 15 Jan 2013 00:34:33 +0000 In-Reply-To: <201301142036.r0EKaYGN005907@como.maths.usyd.edu.au> References: <201301142036.r0EKaYGN005907@como.maths.usyd.edu.au> Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-eTIYiJF0k2H4mifvGy7X" Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: paul.szabo@sydney.edu.au, 695182@bugs.debian.org Cc: dave@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org --=-eTIYiJF0k2H4mifvGy7X Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2013-01-15 at 07:36 +1100, paul.szabo@sydney.edu.au wrote: > Dear Dave, >=20 > >> Seems that any i386 PAE machine will go OOM just by running a few > >> processes. To reproduce: > >> sh -c 'n=3D0; while [ $n -lt 19999 ]; do sleep 600 & ((n=3Dn+1)); do= ne' > >> ... > > I think what you're seeing here is that, as the amount of total memory > > increases, the amount of lowmem available _decreases_ due to inflation > > of mem_map[] (and a few other more minor things). The number of sleeps > > you can do is bound by the number of processes, as you noticed from > > ulimit. Creating processes that don't use much memory eats a relativel= y > > large amount of low memory. > > This is a sad (and counterintuitive) fact: more RAM actually *CREATES* > > RAM bottlenecks on 32-bit systems. >=20 > I understand that more RAM leaves less lowmem. What is unacceptable is > that PAE crashes or freezes with OOM: it should gracefully handle the > issue. [...] Sorry, let me know where to send your refund. Ben. --=20 Ben Hutchings Quantity is no substitute for quality, but it's the only one we've got. --=-eTIYiJF0k2H4mifvGy7X Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIVAwUAUPSkGee/yOyVhhEJAQrbyxAAucDS0JK+jxM1edWyh6x21ngvDqaQ55Wi OfLa+fKTHz2yhZ1A6JoIJuL0xwalbLiAAeIaFVTsUAM410DUhTe2GWwxa/ZC+y1Q tyv4ZIb9BfIbDdsnfK0UlN7QjQVreNDFJEo1asfG1jjxnyupoCp9wr2ikJOc1uuW 1jpDjtc9Dknkxo9cEtHJdf3fMVmZLEUp2sScbtRXX08PA9//EwADz3xvz0gaZcvj QH82Fluh1lJuhjWhDlQoKlFztcGc7QAfCBA14BQIEFw/T2sK6dGVeiBCTo+3vbcm +qavK5lK8MlZ2ibFQ1HarzCkRzQmUiseXhOl4owdlhMNTZLmAixLJHiHpe7ybk6u cjWjklxenWmWTHxBF9tmPr8SJO8Q7e1RL08SCjUtME5wJ2KUHzpvqib49ysyEdwH TqQTEm1VMvFCbq/wYwRKw/jIsM+zg1r+e392QT/zMVAIui8y7whoeL9heyHoC6jF uiOSMnA23+OpawSZDM7knPW0j1K+MTz9p8IlsUa+Z8U6wirw7npLNz/Z4Py++8Dn uJ8WJcQ8n+HXbhWgaFy8cnir4zET35OdgwKq0p6BNqT1PqCDeVFKiDE3khhmUJAY U2LBYk0uzr6NAp1nfjzhPYLhp2TclkCM7wDH/CmZK6sM0r24HTfY3rOfL0S4YKRw PZLopwX7Rak= =28wN -----END PGP SIGNATURE----- --=-eTIYiJF0k2H4mifvGy7X-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org