From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030729Ab2GLTG5 (ORCPT ); Thu, 12 Jul 2012 15:06:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46369 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932833Ab2GLTG4 (ORCPT ); Thu, 12 Jul 2012 15:06:56 -0400 Message-ID: <4FFF2040.1010008@redhat.com> Date: Thu, 12 Jul 2012 15:06:40 -0400 From: Doug Ledford User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120605 Thunderbird/13.0 MIME-Version: 1.0 To: Serge Hallyn CC: "Kirill A. Shutemov" , Andrew Morton , KOSAKI Motohiro , Al Viro , linux-kernel@vger.kernel.org, "Dmitry V. Levin" , Pavel Emelyanov , "Kirill A. Shutemov" Subject: Re: [RFC, PATCH] CLONE_NEWIPC and exit_group() References: <20120626120425.GA10275@otc-wbsnb-06> <20120710085034.GA24645@otc-wbsnb-06> <20120711152422.a1f07bd5.akpm@linux-foundation.org> <20120712150702.GA1897@otc-wbsnb-06> <20120712185452.GA24342@sergelap> In-Reply-To: <20120712185452.GA24342@sergelap> X-Enigmail-Version: 1.4.2 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig6FE79A0C9E64D873E11802DE" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig6FE79A0C9E64D873E11802DE Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 07/12/2012 02:54 PM, Serge Hallyn wrote: > Quoting Kirill A. Shutemov (kirill.shutemov@linux.intel.com): >> On Wed, Jul 11, 2012 at 03:24:22PM -0700, Andrew Morton wrote: >>> Am I reading that right? 1000 forks take 33 seconds, with basically >>> all of it just sitting there asleep? This look quite terrible - what= >>> causes this? >> >> It seems free_nsproxy() + synchronize_rcu() are too heavy to be in >> exit_group() path. Patch below helps: 8s -> ~0.5s for me. >=20 > And sys time goes down by that much too, or only user time? >=20 > Given that, with user namespaces, it'll soon be possible for users who > are unprivileged toward the host to be able to create and destroy > namespaces, if the patch ends up making it easy for a user to consume a= > bunch of system time and not have it accounted at all to himself, then > I think we should keep it as is. Indeed. --=20 Doug Ledford GPG KeyID: 0E572FDD http://people.redhat.com/dledford --------------enig6FE79A0C9E64D873E11802DE Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQIcBAEBAgAGBQJP/yBAAAoJELgmozMOVy/d+XoP/3s2osV01JRBMukKgez1kxMo TJLxUeODIdFwsr2CzBGSgsRz8ycREBUJmr/9jSvX5YYFz2begvUOGR+qVOiQ4aSP O3c1hpIz4fVUHFRpE0xu61TBU35ULnnJYBtqcPgYVZYw4p1qFNXpBRddQxPrIxh7 pRiXOyODOkVZQuKKsL0/cIDHHdtwIQL47WsUPMe62mMf8srzLukcO4+AXi+vHLah Uoi0FC664xYdNy22w9y96s0T6Zw1ADFAYaGhU9YDPSOrg9/L4DeTTtWT/MS5yy/K erM9hkioy42NbnoZX58O6LZOVMLTeEp6SEbPW+yvdzxQpC7UZXRLNIEN4tzK+gIY WmPbAmtOnLqipyMqkr/54iGYhWdRQMyv3yOvHvaVOpiyWd7xlgV6KmlDIe3Jsr+E ql0nB6y7CK6LkRwMqw7prC9YUFo+INNcmsoODaqxMHgTkteTKHckBNj64Wg5dmPy /9Hb2uiQwpn7G1nvM4N2RTZdH5WgpVzzkjSUGfPQgAfXxLDRghDPnxLzBJa/qIL/ YqZqanPquagjsEptyug1l9C5+hzUIS5ITzJy0oIjTeJ3gIo4Hre3CE2mUjB0hSB4 yY8zRgIMcyUdsziIfHHiA9vFmuvV2FhnV7ExOOkpPuoq6E+KY4nHnjyGHxLXP64T +CbXyZzepkPEKVUP8sCi =gRR7 -----END PGP SIGNATURE----- --------------enig6FE79A0C9E64D873E11802DE--