From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id CB6AF6B02A9 for ; Wed, 22 Nov 2017 10:39:36 -0500 (EST) Received: by mail-pg0-f69.google.com with SMTP id z4so8964667pgo.7 for ; Wed, 22 Nov 2017 07:39:36 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id g71si15278241pfg.124.2017.11.22.07.39.35 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 22 Nov 2017 07:39:35 -0800 (PST) Date: Wed, 22 Nov 2017 16:39:32 +0100 From: Michal Hocko Subject: Re: [PATCH] mm: migrate: fix an incorrect call of prep_transhuge_page() Message-ID: <20171122153932.xu3hfodgj2oy3kyd@dhcp22.suse.cz> References: <20171121021855.50525-1-zi.yan@sent.com> <20171122085416.ycrvahu2bznlx37s@dhcp22.suse.cz> <20171122134059.fmyambktkel4e3zq@dhcp22.suse.cz> <5A158D22.3040609@cs.rutgers.edu> <20171122145307.52klaq4ouorngsss@dhcp22.suse.cz> <5A159319.6070403@cs.rutgers.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5A159319.6070403@cs.rutgers.edu> Sender: owner-linux-mm@kvack.org List-ID: To: Zi Yan Cc: Zi Yan , Naoya Horiguchi , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrea Reale , =?iso-8859-1?B?Suly9G1l?= Glisse , stable@vger.kernel.org On Wed 22-11-17 10:09:13, Zi Yan wrote: > > > Michal Hocko wrote: > > On Wed 22-11-17 09:43:46, Zi Yan wrote: > >> > >> Michal Hocko wrote: [...] > >>> but why is unsafe to enable the feature on other arches which support > >>> THP? Is there any plan to do the next step and remove this config > >>> option? > >> Because different architectures have their own way of specifying a swap > >> entry. This means, to support THP migration, each architecture needs to > >> add its own __pmd_to_swp_entry() and __swp_entry_to_pmd(), which are > >> used for arch-independent pmd_to_swp_entry() and swp_entry_to_pmd(). > > > > I understand that part. But this smells like a matter of coding, no? > > I was suprised to see the note about safety which didn't make much sense > > to me. > > And testing as well. I had powerpc book3s support in my initial patch > submission, but removed it because I do not have access to the powerpc > machine any more. I also tried ARM64, which seems working by adding the > code, but I have no hardware to test it now. > > Any suggestions? Cc arch maintainers and mailing lists? -- Michal Hocko SUSE Labs -- 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