Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754813AbaFYHEf (ORCPT ); Wed, 25 Jun 2014 03:04:35 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:50688 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752881AbaFYHEW (ORCPT ); Wed, 25 Jun 2014 03:04:22 -0400 Message-ID: <53AA746A.3030303@canonical.com> Date: Wed, 25 Jun 2014 09:04:10 +0200 From: Stefan Bader User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: David Rientjes CC: Heiko Carstens , linux-kernel@vger.kernel.org, Eric Dumazet , Andrew Morton , Peter Zijlstra Subject: Re: fs/stat: Reduce memory requirements for stat_open References: <1402578017-16637-1-git-send-email-stefan.bader@canonical.com> <20140612134149.GC4296@osiris> <5399B301.9030108@canonical.com> In-Reply-To: X-Enigmail-Version: 1.5.2 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="NNBg5ngqFCgUwKnOX5CsvgJAuGCVA4DR0" 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 4880 and 3156) --NNBg5ngqFCgUwKnOX5CsvgJAuGCVA4DR0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 25.06.2014 01:44, David Rientjes wrote: > On Thu, 12 Jun 2014, Stefan Bader wrote: >=20 >> doh, so you guys have been hit by that before. And I have missed the f= act that >> single_open is special. Which makes the change for the upper limit do = the wrong >> thing. While long-term it sounds like changing it to vmalloc or iterat= ive reads >> sounds better, maybe the change from possible to online cpus might be = something >> that is better acceptable as a quick fix... Not sure. At least this gi= ving back >> a bit of attention to the matter and it is not only affecting zSeries.= x86 >> starts to see hw that requires a similar high possible cpus... :) >> >=20 > Heiko's patches that should fix this problem are now in -mm, so it woul= d=20 > be nice to know if there are any existing issues that haven't been=20 > addressed yet with your bug report. See=20 > http://www.ozlabs.org/~akpm/mmotm/ >=20 Heiko and I both had the same issue. Since some x86 hardware also reaches= a lot of CPUs (hyperthreads included), we bumped the possible number of CPUs to= 256 at least for the 64bit kernel. And that resulted in failed accesses to /proc= /stat when memory became fragmented. So the first patch will avoid this on most systems. I have not seen this = myself, but I would expect him to be happy with 1/2 already. For really excessive= hardware 2/2 will close the gap. Since this is no critical bug, I am fine with 3.17, too. I have not done = so, yet, but I could let our reporter try the patches (again, probably not ve= rifying the second part). Just waited to do so to see whether the code settles do= wn to these changes. -Stefan --NNBg5ngqFCgUwKnOX5CsvgJAuGCVA4DR0 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBCgAGBQJTqnRzAAoJEOhnXe7L7s6jLlsP/37pLWV3+B3kJ2CStZ7bvQ+T FBw6xpLjzu5ayIQuzvN6amSqyAmpjc6GrbzBH75oaKP+NP9900sizIrD88Kjv4PC Cs3fvx2f8CBv/08p/LexmawlWz+dIeW3R8lDv87AZHmYDEEaVuqLKCUnhuzAmjf+ gbQB6H8PMtsPMoFv8B/+ptnB0UcT9gEpZxYI7S65DIUuRb85i6m7/57pUKfurekr cbt33Yl2wDyLhYqw5tXs/miGGi3psGwL+r4VRWAk72+daYVo0uaf7w9rkO+5mLC2 AOCGyU8wjMaXH9ZoUcLFSB+m33Of2/qUzYsM6mglX/3k97pMTDU/a4GCgwQJV97/ BEUlABTP9/DbNgpV1RbtkxfdCzs3wds3n1wnnUi/kyzilgDrF3cCgRgMTzeiJbK7 nvj6UpHEBRiTlgTS6af0Av5GhgAVnArY0tUQ8MveABv8nV3xG8S/V7mc/g4vIDQ2 E8aHwAoMOm6VluTB9NJJWu+h8fR2G/P1KVhFSlSmV7Zis1KnoRWZQT7v+crx1T6Q QR9B02nZFuy6EIfI91x5RqwXQLm0X9xduufNaFORdiI29aUrn9+ylYgSJ9fFD7sF jrB22djaceieMnOZzOUokQrcrcAKoshrJ5+vPDtTZsdrGrRyJyDXKjr138MWudre k8jQ+c75NBkwBlhtkRpH =/XxE -----END PGP SIGNATURE----- --NNBg5ngqFCgUwKnOX5CsvgJAuGCVA4DR0-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/