From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) by kanga.kvack.org (Postfix) with ESMTP id D39056B46E9 for ; Tue, 28 Aug 2018 11:24:18 -0400 (EDT) Received: by mail-ed1-f72.google.com with SMTP id w44-v6so971041edb.16 for ; Tue, 28 Aug 2018 08:24:18 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id a24-v6si1435766edt.342.2018.08.28.08.24.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 Aug 2018 08:24:17 -0700 (PDT) Date: Tue, 28 Aug 2018 17:24:14 +0200 From: Michal Hocko Subject: Re: [PATCH 4/7] mm/hmm: properly handle migration pmd Message-ID: <20180828152414.GQ10223@dhcp22.suse.cz> References: <20180824192549.30844-1-jglisse@redhat.com> <20180824192549.30844-5-jglisse@redhat.com> <0560A126-680A-4BAE-8303-F1AB34BE4BA5@cs.rutgers.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0560A126-680A-4BAE-8303-F1AB34BE4BA5@cs.rutgers.edu> Sender: owner-linux-mm@kvack.org List-ID: To: Zi Yan Cc: jglisse@redhat.com, linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org, "Aneesh Kumar K . V" , Ralph Campbell , John Hubbard On Fri 24-08-18 20:05:46, Zi Yan wrote: [...] > > + if (!pmd_present(pmd)) { > > + swp_entry_t entry = pmd_to_swp_entry(pmd); > > + > > + if (is_migration_entry(entry)) { > > I think you should check thp_migration_supported() here, since PMD migration is only enabled in x86_64 systems. > Other architectures should treat PMD migration entries as bad. How can we have a migration pmd entry when the migration is not supported? -- Michal Hocko SUSE Labs