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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A4C1DC433FE for ; Fri, 14 Jan 2022 18:57:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 239C76B0071; Fri, 14 Jan 2022 13:57:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1E8FA6B0073; Fri, 14 Jan 2022 13:57:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 089F66B0074; Fri, 14 Jan 2022 13:57:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0239.hostedemail.com [216.40.44.239]) by kanga.kvack.org (Postfix) with ESMTP id ED1A26B0071 for ; Fri, 14 Jan 2022 13:57:08 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id AE71E82F4BF0 for ; Fri, 14 Jan 2022 18:57:08 +0000 (UTC) X-FDA: 79029800136.27.228DB74 Received: from mail-pl1-f173.google.com (mail-pl1-f173.google.com [209.85.214.173]) by imf25.hostedemail.com (Postfix) with ESMTP id 64E98A0015 for ; Fri, 14 Jan 2022 18:57:08 +0000 (UTC) Received: by mail-pl1-f173.google.com with SMTP id e8so256455plh.8 for ; Fri, 14 Jan 2022 10:57:08 -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=YabguVGMf1wsrLonybEy7GRmC4KIXzc8d3V33tngp/k=; b=BNkdw/wh6LH8w0iEL7y9mRnL7JUYIA3P/U0BRZLrJbpTwamsTrd3mzbMjtnNHRN7v4 +S5gXh4ccZUXYy2SFitNDcBX5gV8xkC4vxhRBD4Te4n0ny3LT2EOnhGtU+5o4srLrWhk mnayMbiByRLiYmIrmWcKo3Q2MsAVhAgbA2JAgaTHeomjOsEPTRHGttdoapY1obh9mVvn LBMJH8XRiWkoD9q5UJaB6C520GJ27hYAiT84F56S1l8i8ZuwNDtOniXuKB51kVN0s593 b0o+ehUSWxYNdQQNpvW2KxJYY/eNLucMSbeJrNOkebNjKyOkaOT4QQycRu3CQmDTcg+f e3FA== 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=YabguVGMf1wsrLonybEy7GRmC4KIXzc8d3V33tngp/k=; b=2vZHI2LgbwtsFt4NBjVV2COGwTum/q485s77+OlXfGfSxshGBRlF83bcHZ06tWc9vw zzGuylTk5bN9PhYggqjc1veViNcB5EBryD/H/KyJbK4WGlrYstYTWvyJ7GPoclsTnCUY fb/PbZqOs/N0ueqDxl1p6GTZ8n5wOWpnHCpL6VhiaVoOFaFTCzazBZ9grJsOURxf8v8C iNhge3m3CORP66AKfzsCqUq7BAT4v03YpZ02BXu+BS90BfwsFLZh4goklZU0n0eLc24+ IaLPiogzHXXZ2NNkF3sUtCmrmcvLTdI7PRKGBEPyIAz+JVcTH5cbl/3dUVwTyErz+J+m +gIw== X-Gm-Message-State: AOAM5313/Ocu7jRmpJwMMDEOdxz8+rzEJnrJJxLpYgj6YHVhVhZg/5jd bCz3UYGykKoXaTORp0IoQQA= X-Google-Smtp-Source: ABdhPJxglYK9nWP4cyYX2JxAIwtXPJz4Ogbq2I60+DHXHnuDTEfjzEyC8nX9XFjNT13GmDdPuNncGg== X-Received: by 2002:a17:90b:1a88:: with SMTP id ng8mr21769882pjb.180.1642186626607; Fri, 14 Jan 2022 10:57:06 -0800 (PST) Received: from google.com ([2620:15c:211:201:a5b:82ad:7990:3ae0]) by smtp.gmail.com with ESMTPSA id h189sm1470896pfg.141.2022.01.14.10.57.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Jan 2022 10:57:06 -0800 (PST) Date: Fri, 14 Jan 2022 10:57:04 -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: <51fc9dfe-1cac-69f6-0c68-46a83fd7783d@redhat.com> X-Rspamd-Queue-Id: 64E98A0015 X-Stat-Signature: d9h4qfd36jfjqtjsk73h7crts15cz6kk Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b="BNkdw/wh"; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none); spf=pass (imf25.hostedemail.com: domain of minchan.kim@gmail.com designates 209.85.214.173 as permitted sender) smtp.mailfrom=minchan.kim@gmail.com X-Rspamd-Server: rspam08 X-HE-Tag: 1642186628-565644 X-Bogosity: Ham, tests=bogofilter, spamicity=0.017937, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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!