From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756965AbbCCRlI (ORCPT ); Tue, 3 Mar 2015 12:41:08 -0500 Received: from prod-mail-xrelay07.akamai.com ([72.246.2.115]:30425 "EHLO prod-mail-xrelay07.akamai.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755850AbbCCRlG (ORCPT ); Tue, 3 Mar 2015 12:41:06 -0500 Date: Tue, 3 Mar 2015 12:41:05 -0500 From: Eric B Munson To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Peter Zijlstra Cc: Christoph Lameter , Thomas Gleixner , Andrew Morton , Hugh Dickins , Mel Gorman , Roland Dreier , Sean Hefty , Hal Rosenstock , Mike Marciniszyn Subject: Resurrecting the VM_PINNED discussion Message-ID: <20150303174105.GA3295@akamai.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="bg08WKrSYDhXBjb5" Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --bg08WKrSYDhXBjb5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable All, After LSF/MM last year Peter revived a patch set that would create infrastructure for pinning pages as opposed to simply locking them. AFAICT, there was no objection to the set, it just needed some help =66rom the IB folks. Am I missing something about why it was never merged? I ask because Akamai has bumped into the disconnect between the mlock manpage, Documentation/vm/unevictable-lru.txt, and reality WRT compaction and locking. A group working in userspace read those sources and wrote a tool that mmaps many files read only and locked, munmapping them when they are no longer needed. Locking is used because they cannot afford a major fault, but they are fine with minor faults. This tends to fragment memory badly so when they started looking into using hugetlbfs (or anything requiring order > 0 allocations) they found they were not able to allocate the memory. They were confused based on the referenced documentation as to why compaction would continually fail to yield appropriately sized contiguous areas when there was more than enough free memory. I would like to see the situation with VM_LOCKED cleared up, ideally the documentation would remain and reality adjusted to match and I think Peter's VM_PINNED set goes in the right direction for this goal. What is missing and how can I help? Thanks, Eric --bg08WKrSYDhXBjb5 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJU9fIxAAoJELbVsDOpoOa9fhIQANddQaLa/xGNR1aFZx7HdBK3 FbE0KtCituCbCv/qXJ6C/4yJEGqW08gH9CGoVRGiE4Q+5hAHg4sBlMySOQH19M15 2WtQ+m2j169MuXvhZwzNv2olR9WpvoMBqIsaG5wDUgGCIRr1WFlTZcOgstgla87A +UeFryrytITupVtXIFJMdmi8H/wNhgyYDR2LRv8dKQNj7+cpQRiifmxeNS9Q7SfU 2LWxwwaK84G90cBaf3tEPA1Sfp6KhUZ9rG/WTjPv4iWVkXSYV4ru8MIBI9/m9Zz9 /qV6lDfMeRwph5riUg6UA5ZXlLClbwLO74S/OIdkjMIBWsyQRSzJTmOCX/q+j3B+ dA7HDlqI7g+ppo9mHCRHKKvmj0suxH5GS/GXeLPWz2s0HWzyFWGLbqlLDEi7UGCG XT04ToeUt7rsR9TmX79MpiQz/z8/exrvaaYveS3Ds+BBqw4z1hflp4JtIYvwlquy YO1eIyTqZ8cxwTwyaA5eA1xJZnkesDfoMCxYsQduNVNUpfphTX9UA1pAfRG06we4 4AeGK0rDEpG3h8idG9rFX2xS9/kjJk647nWt7qv8FxCVo9+mQuGonIG29bBzcnOq 9oRuXLs7yEmzZWUVlJCKGOtp1AcWryAdIJ3NbHPVljF4bzjb631DPnF4pRqOnIMh oWlnIe/hJs4XqYZInIM9 =fVgt -----END PGP SIGNATURE----- --bg08WKrSYDhXBjb5--