From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f197.google.com (mail-io0-f197.google.com [209.85.223.197]) by kanga.kvack.org (Postfix) with ESMTP id 356396B0033 for ; Tue, 31 Jan 2017 14:54:46 -0500 (EST) Received: by mail-io0-f197.google.com with SMTP id c80so189173045iod.4 for ; Tue, 31 Jan 2017 11:54:46 -0800 (PST) Received: from NAM01-SN1-obe.outbound.protection.outlook.com (mail-sn1nam01on0130.outbound.protection.outlook.com. [104.47.32.130]) by mx.google.com with ESMTPS id p73si11046148itc.10.2017.01.31.11.54.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 31 Jan 2017 11:54:45 -0800 (PST) Message-ID: <5890EB58.3050100@cs.rutgers.edu> Date: Tue, 31 Jan 2017 13:54:00 -0600 From: Zi Yan MIME-Version: 1.0 Subject: Re: [PATCH v2 00/12] mm: page migration enhancement for thp References: <1478561517-4317-1-git-send-email-n-horiguchi@ah.jp.nec.com> In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enig69312C755C158C734ACD21BC" Sender: owner-linux-mm@kvack.org List-ID: To: Anshuman Khandual , Andrew Morton , Naoya Horiguchi , "Kirill A. Shutemov" Cc: linux-mm@kvack.org, Hugh Dickins , Dave Hansen , Andrea Arcangeli , Mel Gorman , Michal Hocko , Vlastimil Babka , Pavel Emelyanov , Balbir Singh , linux-kernel@vger.kernel.org, Naoya Horiguchi --------------enig69312C755C158C734ACD21BC Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable I am also doing some tests on THP migration and discover that there are some corner cases not handled in this patchset. For example, in handle_mm_fault, without taking pmd_lock, the kernel may see pmd_none(*pmd) during THP migrations, which leads to handle_pte_fault or even deeper in the code path. At that moment, pmd_trans_unstable() will treat a pmd_migration_entry as pmd_bad and clear it. This leads to application crashing and page table leaks, since a deposited PTE page is not released when the application crashes. Even after I add is_pmd_migration_entry() into pmd_trans_unstable(), I still see application data corruptions. I hope someone can shed some light on how to debug this. Should I also look into pmd_trans_huge() call sites where pmd_migration_entry should be handled differently? Thanks. Anshuman Khandual wrote: > On 11/08/2016 05:01 AM, Naoya Horiguchi wrote: >> Hi everyone, >> >> I've updated thp migration patches for v4.9-rc2-mmotm-2016-10-27-18-27= >> with feedbacks for ver.1. >=20 > Hello Noaya, >=20 > I have been working with Zi Yan on the parallel huge page migration ser= ies > (https://lkml.org/lkml/2016/11/22/457) and planning to post them on top= of > this THP migration enhancement series. Hence we were wondering if you h= ave > plans to post a new version of this series in near future ? >=20 > Regards > Anshuman >=20 --=20 Best Regards, Yan Zi --------------enig69312C755C158C734ACD21BC Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBCAAGBQJYkOt/AAoJEEGLLxGcTqbMEmgH/RGfR7f5boRco6eWExeZ1adJ 6kRYWmYXipya1xJV7afp+px+MVsHA86IuCM2j+p/tSW000vRge2ydfIgHxrmIk1Q pzXu1ILdMr91/sST1Zz4EBHSU2cB40EsbPq0nUT9OGda67XCWCcW7c6H9HQagMFm w3NtHXgseJmr8vjcX5d44z1/zSBdDUQ1yNE8dzYHV5hZ7Mq47oRHju35pox+bQ6I BOfRyDDtNAOuRGigEowTPBE8iLuoCQk9Ij0Re6NmBRIRquWrUYm0Up85iOGBK96a GRL9vBAVZRAXNkVOygjwnSYxRKcbr05P0uIp6P/SWhtnoALneWA906M7nXqDHZA= =fpdi -----END PGP SIGNATURE----- --------------enig69312C755C158C734ACD21BC-- -- 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