From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE1C6C433F5 for ; Fri, 21 Jan 2022 21:59:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232566AbiAUV7g (ORCPT ); Fri, 21 Jan 2022 16:59:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229484AbiAUV7f (ORCPT ); Fri, 21 Jan 2022 16:59:35 -0500 Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34BFBC06173B for ; Fri, 21 Jan 2022 13:59:35 -0800 (PST) Received: by mail-pf1-x429.google.com with SMTP id 192so6600589pfz.3 for ; Fri, 21 Jan 2022 13:59:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=SiF8IN8PI2SpOhltyDuyXyX1icsw8zFtbfQW5dLEeIU=; b=bQLtven7ZpIOTGbqDDlpV0R8fx++Zh/uDyeixVXjLWLQbECONlYdFuIC7JV++9VGfq L7oIwYoibLXUdY+lkGynvZaYUWXHddV1R5DPK3AAhoUVsV/be7wk5zLGWl8PdW069sZ4 ufOTYHXzMz/Twt6l0dmTfyB+ejL4fVqJZIGdPlVdWWQfKEiYfRPSbig4WUQJ9xWDxS3z c+BmC+a8rHYy5O4+r1YPk62rUHeYwnPN3NUQ20FZ8W38eEuxbhaULQAHjt0NNiD1oCOX asmRkTXx0CfHx1nbbVQNW3Ay459W5oZ0Ur2CQxsS/wlCyiAvJh+Sef9Jb6D6Z65RS9xt 8cTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=SiF8IN8PI2SpOhltyDuyXyX1icsw8zFtbfQW5dLEeIU=; b=ROsp5Rrwr0bQXlQz8BM0SxQxbGtPCOvGSo7ZSTTVbVRUFSPXsC1axrkWeiMDgPbcoU gO1PnjxU1f/+FREAjPmHtTKrviSaALFvGZtjXBfhgMDoVDyYE6uBMHVvD9u6z9ftErs6 qm5OtugrkkycSSK22y5YStLfbJD5eAT0M5K6aEbTOelbPbq0/Egou7X9bZ4QLhFpfg0x kLMHe+Q/RAMXc9TtV5VzXLnNOOKRlal7RtqPUApXJMDboojC81vLqMk8sbL4LM0PZU3X gScnwcnsCxgZWSb3KDOgPhpchftlbvVm7zob7YaZtFN4ary9sj6136q8WFNjgvtnQoFG LP7g== X-Gm-Message-State: AOAM533p9/f2fso9BZx1B9XmnVR1VuMT1GKzobDDeO8rD8HgJ37P+J5D AMT6eFlWRJ6zWzaq+SjLAro= X-Google-Smtp-Source: ABdhPJxa4iGkdzZELLkg3VVFmGIENpXhmp6sYfBK8j0mtfYdRtI9SxOwZjPwx4RFe43hETjrR5YW4Q== X-Received: by 2002:a63:370b:: with SMTP id e11mr4329422pga.558.1642802374609; Fri, 21 Jan 2022 13:59:34 -0800 (PST) Received: from google.com ([2620:15c:211:201:8ee4:9dbe:c4bd:f5f8]) by smtp.gmail.com with ESMTPSA id u35sm8088563pfg.195.2022.01.21.13.59.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Jan 2022 13:59:34 -0800 (PST) Sender: Minchan Kim Date: Fri, 21 Jan 2022 13:59:32 -0800 From: Minchan Kim To: David Hildenbrand Cc: Andrew Morton , Michal Hocko , linux-mm , LKML , Suren Baghdasaryan , John Dias , huww98@outlook.com, John Hubbard Subject: Re: [RFC v2] mm: introduce page pin owner Message-ID: References: <20211228175904.3739751-1-minchan@kernel.org> <35d7f27c-44e3-3921-c8d3-b6dee3b01238@redhat.com> <8f02e71b-5de7-4342-7371-a7fe19b114b5@redhat.com> <51fc9dfe-1cac-69f6-0c68-46a83fd7783d@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 14, 2022 at 10:57:04AM -0800, Minchan Kim wrote: > On Fri, Jan 14, 2022 at 07:47:49PM +0100, David Hildenbrand wrote: > > > > >>>>>> Otherwise, I'd like to have feature naming more higher level>>>>>> to represent page migration failure and then tracking unref of > > >>>>>> the page. In the sense, PagePinOwner John suggested was good > > >>>>>> candidate(Even, my original naming PagePinner was worse) since > > >>>>> > > >>>>> Personally, I dislike both variants. > > >>>>> > > >>>>>> I was trouble to abstract the feature with short word. > > >>>>>> If we approach "what feature is doing" rather than "what's > > >>>>>> the feature's goal"(I feel the your suggestion would be close > > >>>>>> to what feature is doing), I'd like to express "unreference on > > >>>>>> migraiton failed page" so PAGE_EXT_UNMIGRATED_UNREF > > >>>>>> (However, I prefer the feature naming more "what we want to achieve") > > >>>>>> > > >>>>> E.g., PAGE_EXT_TRACE_UNREF will trace unref to the page once the bit is > > >>>>> set. The functionality itself is completely independent of migration > > >>>>> failures. That's just the code that sets it to enable the underlying > > >>>>> tracing for that specific page. > > >>>> > > >>>> I agree that make something general is great but I also want to avoid > > >>>> create something too big from the beginning with just imagination. > > >>>> So, I'd like to hear more concrete and appealing usecases and then > > >>>> we could think over this trace approach is really the best one to > > >>>> achieve the goal. Once it's agreed, the naming you suggested would > > >>>> make sense. > > >>> > > >>> At least for me it's a lot cleaner if a feature clearly expresses what > > >>> it actually does. Staring at PAGE_EXT_PIN_OWNER I initially had no clue. > > >>> I was assuming we would actually track (not trace!) all active FOLL_PIN > > >>> (not unref callers!). Maybe that makes it clearer why I'd prefer a > > >>> clearer name. > > >> > > >> I totally agree PagePinOwner is not 100% straightforward. I'm open for > > >> other better name. Currently we are discussing how we could generalize > > >> and whether it's useful or not. Depending on the discussion, the design/ > > >> interface as well as naming could be changed. No problem. > > > > > > PagePinOwner is just highly misleading. Because that's not what the > > > feature does. Having that said, i hope we'll get other opinions as well. > > > > FWIW, I think "page reference holder" would be clearer. PageRefHolder or > > PageReferenceHolder > > > > "Trace page reference holders on unref after migration of a page failed." > > Ah, crossed email. PageRefHolder. Yeah, sounds like better! David, I will change the naming to PageRefHolder and update the other code/comments to follow it. Do you have any objection? Otherwise, I'd like to post next version to make the work proceeding. Thanks.