From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755108AbbCBUmg (ORCPT ); Mon, 2 Mar 2015 15:42:36 -0500 Received: from mail-wg0-f48.google.com ([74.125.82.48]:38049 "EHLO mail-wg0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751914AbbCBUmd convert rfc822-to-8bit (ORCPT ); Mon, 2 Mar 2015 15:42:33 -0500 From: Michal Nazarewicz To: Stefan Strogin , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Joonsoo Kim , Andrew Morton , Marek Szyprowski , aneesh.kumar@linux.vnet.ibm.com, Laurent Pinchart , Dmitry Safonov , Pintu Kumar , Weijie Yang , Laura Abbott , SeongJae Park , Hui Zhu , Minchan Kim , Dyasly Sergey , Vyacheslav Tyrtov , Aleksei Mateosian , gregory.0xf0@gmail.com, sasha.levin@oracle.com, gioh.kim@lge.com, pavel@ucw.cz, stefan.strogin@gmail.com Subject: Re: [PATCH v3 3/4] mm: cma: add list of currently allocated CMA buffers to debugfs In-Reply-To: <54F48560.1090800@partner.samsung.com> Organization: http://mina86.com/ References: <1fe64ae6f12eeda1c2aa59daea7f89e57e0e35a9.1424802755.git.s.strogin@partner.samsung.com> <54F48560.1090800@partner.samsung.com> User-Agent: Notmuch/0.19+53~g2e63a09 (http://notmuchmail.org) Emacs/25.0.50.1 (x86_64-unknown-linux-gnu) X-Face: PbkBB1w#)bOqd`iCe"Ds{e+!C7`pkC9a|f)Qo^BMQvy\q5x3?vDQJeN(DS?|-^$uMti[3D*#^_Ts"pU$jBQLq~Ud6iNwAw_r_o_4]|JO?]}P_}Nc&"p#D(ZgUb4uCNPe7~a[DbPG0T~!&c.y$Ur,=N4RT>]dNpd;KFrfMCylc}gc??'U2j,!8%xdD Face: 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 X-PGP: 50751FF4 X-PGP-FP: AC1F 5F5C D418 88F8 CC84 5858 2060 4012 5075 1FF4 X-Hashcash: 1:20:150302:a.mateosian@samsung.com::Pvu91eDaJqxXVIir:0000000000000000000000000000000000000004et X-Hashcash: 1:20:150302:minchan@kernel.org::8u2VIrDBlcoBn0tp:00000000000000000000000000000000000000000000GTz X-Hashcash: 1:20:150302:akpm@linux-foundation.org::7MeP1bO7rEl2tGXp:0000000000000000000000000000000000000Qhn X-Hashcash: 1:20:150302:stefan.strogin@gmail.com::4/WFFkecpCM5eWgH:00000000000000000000000000000000000000jjR X-Hashcash: 1:20:150302:pavel@ucw.cz::X8G8jZZMkmgBpHdA:000000+nN X-Hashcash: 1:20:150302:v.tyrtov@samsung.com::qoAUo2iURTA+CJ4m:000000000000000000000000000000000000000000h8F X-Hashcash: 1:20:150302:sj38.park@gmail.com::hJfKLO3Uiqa/Ok6A:0000000000000000000000000000000000000000000f6b X-Hashcash: 1:20:150302:d.safonov@partner.samsung.com::H+c5q81/bH5fc36w:000000000000000000000000000000000MxY X-Hashcash: 1:20:150302:iamjoonsoo.kim@lge.com::gs2xfY7k6Y2E3m0q:00000000000000000000000000000000000000017vD X-Hashcash: 1:20:150302:linux-mm@kvack.org::nsrZWFtr2LW2MDsH:00000000000000000000000000000000000000000001nGd X-Hashcash: 1:20:150302:s.strogin@partner.samsung.com::sn6IsHKdWugZrJ0p:000000000000000000000000000000001fjW X-Hashcash: 1:20:150302:weijie.yang@samsung.com::BcY96Gp17DwZNVEk:0000000000000000000000000000000000000025PZ X-Hashcash: 1:20:150302:aneesh.kumar@linux.vnet.ibm.com::h/j8lKX0c5kjfFq2:0000000000000000000000000000002L9J X-Hashcash: 1:20:150302:linux-kernel@vger.kernel.org::pM2JpXh3GFy4slOi:0000000000000000000000000000000002kWW X-Hashcash: 1:20:150302:pintu.k@samsung.com::XFwxX1G+az5wg3dt:0000000000000000000000000000000000000000003gRa X-Hashcash: 1:20:150302:laurent.pinchart@ideasonboard.com::3iDzFQnfJXa5XHM2:000000000000000000000000000046sj X-Hashcash: 1:20:150302:m.szyprowski@samsung.com::wCJclJ9mDx3J0CV4:00000000000000000000000000000000000004ixy X-Hashcash: 1:20:150302:zhuhui@xiaomi.com::t3o6Ckf6/zfPRmwY:000000000000000000000000000000000000000000004cgy X-Hashcash: 1:20:150302:lauraa@codeaurora.org::heMVZjr0VdU2iys3:00000000000000000000000000000000000000005cU/ X-Hashcash: 1:20:150302:s.dyasly@samsung.com::L9wBZcd/G+prYs9k:0000000000000000000000000000000000000000074ZM X-Hashcash: 1:20:150302:gioh.kim@lge.com::77l6dxwGg9smJ5yB:09pOd X-Hashcash: 1:20:150302:sasha.levin@oracle.com::R65n1MLs+mURMCEY:000000000000000000000000000000000000000FTO3 X-Hashcash: 1:20:150302:gregory.0xf0@gmail.com::tqFC6Q2vWHse43e6:000000000000000000000000000000000000000FgUk Date: Mon, 02 Mar 2015 21:42:28 +0100 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 02 2015, Stefan Strogin wrote: > My fault. You are right. > I'm not sure how to do the output nice... I could use *ppos to point the > number of next list entry to read (like that is used in > read_page_owner()). But in this case the list could be changed before we > finish reading, it's bad. > Or we could use seq_files like in v1, iterating over buffer_list > entries. But seq_print_stack_trace() has to be added. I’m not that familiar with seq_* so my opinion may be ill-informed, but I feel that skipping some entries while (de)allocations happen is akin to process reading a file while some other process modifies it. This is a debug function so perhaps it’s acceptable that it may return garbage if not used carefully? -- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michał “mina86” Nazarewicz (o o) ooo +------ooO--(_)--Ooo--