From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f72.google.com (mail-oi0-f72.google.com [209.85.218.72]) by kanga.kvack.org (Postfix) with ESMTP id 5B6A66B0296 for ; Mon, 4 Dec 2017 07:57:35 -0500 (EST) Received: by mail-oi0-f72.google.com with SMTP id f13so7639569oib.20 for ; Mon, 04 Dec 2017 04:57:35 -0800 (PST) Received: from szxga04-in.huawei.com (szxga04-in.huawei.com. [45.249.212.190]) by mx.google.com with ESMTPS id g2si4434617otb.63.2017.12.04.04.57.31 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 04 Dec 2017 04:57:34 -0800 (PST) Message-ID: <5A25460F.9050206@huawei.com> Date: Mon, 4 Dec 2017 20:56:47 +0800 From: zhong jiang MIME-Version: 1.0 Subject: Re: [patch 13/15] mm/page_owner: align with pageblock_nr pages 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> <20171204123546.lhhcbpulihz3upm6@dhcp22.suse.cz> In-Reply-To: <20171204123546.lhhcbpulihz3upm6@dhcp22.suse.cz> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Vlastimil Babka , akpm@linux-foundation.org, linux-mm@kvack.org On 2017/12/4 20:35, Michal Hocko wrote: > 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. > yes, limited by my knowledge and english. Maybe Vlastimil can address it in detail. Thanks zhongjiang -- 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