From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id 7D2006B0281 for ; Mon, 4 Dec 2017 07:35:49 -0500 (EST) Received: by mail-pg0-f72.google.com with SMTP id w1so11386743pgq.21 for ; Mon, 04 Dec 2017 04:35:49 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id q3si7895053pgp.97.2017.12.04.04.35.48 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 04 Dec 2017 04:35:48 -0800 (PST) Date: Mon, 4 Dec 2017 13:35:46 +0100 From: Michal Hocko Subject: Re: [patch 13/15] mm/page_owner: align with pageblock_nr pages Message-ID: <20171204123546.lhhcbpulihz3upm6@dhcp22.suse.cz> References: <5a208318./AHclpWAWggUsQYT%akpm@linux-foundation.org> <8c2af1ab-e64f-21da-f295-ea1ead343206@suse.cz> <20171201171517.lyqukuvuh4cswnla@dhcp22.suse.cz> <5A2536B0.5060804@huawei.com> <20171204120114.iezicg6pmyj2z6lq@dhcp22.suse.cz> <5A253E55.7040706@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5A253E55.7040706@huawei.com> Sender: owner-linux-mm@kvack.org List-ID: To: zhong jiang Cc: Vlastimil Babka , akpm@linux-foundation.org, linux-mm@kvack.org On Mon 04-12-17 20:23:49, zhong jiang wrote: > On 2017/12/4 20:01, Michal Hocko wrote: > > On Mon 04-12-17 19:51:12, zhong jiang wrote: > >> On 2017/12/2 1:15, Michal Hocko wrote: > >>> On Fri 01-12-17 17:58:28, Vlastimil Babka wrote: > >>>> On 11/30/2017 11:15 PM, akpm@linux-foundation.org wrote: > >>>>> From: zhong jiang > >>>>> Subject: mm/page_owner: align with pageblock_nr pages > >>>>> > >>>>> When pfn_valid(pfn) returns false, pfn should be aligned with > >>>>> pageblock_nr_pages other than MAX_ORDER_NR_PAGES in init_pages_in_zone, > >>>>> because the skipped 2M may be valid pfn, as a result, early allocated > >>>>> count will not be accurate. > >>>>> > >>>>> Link: http://lkml.kernel.org/r/1468938136-24228-1-git-send-email-zhongjiang@huawei.com > >>>>> Signed-off-by: zhong jiang > >>>>> Cc: Michal Hocko > >>>>> Signed-off-by: Andrew Morton > >>>> The author never responded and Michal Hocko basically NAKed it in > >>>> https://lkml.kernel.org/r/<20160812130727.GI3639@dhcp22.suse.cz> > >>>> I think we should drop it. > >>> Or extend the changelog to actually describe what kind of problem it > >>> fixes and do an additional step to unigy > >>> MAX_ORDER_NR_PAGES/pageblock_nr_pages > >>> > >> Hi, Michal > >> > >> IIRC, I had explained the reason for patch. if it not. I am so sorry for that. > >> > >> when we select MAX_ORDER_NR_PAGES, the second 2M will be skiped. > >> it maybe result in normal pages leak. > >> > >> meanwhile. as you had said. it make the code consistent. why do not we do it. > >> > >> I think it is reasonable to upstream the patch. maybe I should rewrite the changelog > >> and repost it. > >> > >> Michal, Do you think ? > > Yes, rewrite the patch changelog and make it _clear_ what it fixes and > > under _what_ conditions. There are also other places using > > MAX_ORDER_NR_PAGES rathern than pageblock_nr_pages. Do they need to be > > updated as well? > in the lastest kernel. according to correspond context, I can not find the candidate. :-) git grep says some in page_ext.c, memory_hotplug.c and few in the arch code. I belive we really want to describe and document the distinction between the two constants and explain when to use which one. -- 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