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 AC2E3C25B07 for ; Thu, 4 Aug 2022 22:17:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235319AbiHDWRw (ORCPT ); Thu, 4 Aug 2022 18:17:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230266AbiHDWRu (ORCPT ); Thu, 4 Aug 2022 18:17:50 -0400 Received: from mail-pg1-x52e.google.com (mail-pg1-x52e.google.com [IPv6:2607:f8b0:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 380E161D68 for ; Thu, 4 Aug 2022 15:17:49 -0700 (PDT) Received: by mail-pg1-x52e.google.com with SMTP id 13so1080595pgc.8 for ; Thu, 04 Aug 2022 15:17:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=sV7vlp9vVqtESovTZq4J4qUrClPc07IPwMZZmtZmWxI=; b=ED+ZBw0+7Ig7TW12P74TnVQTzI336MvtfhJaW3/mGmifFHZ9oxFUcuQS5+l9YNvlHW dqyC69YrgBTrNeV391PFe3DqXkzGW7qTTPasyptA8QRIObfywnF37ZqJxrYmuiAqCKpy ruX1JTrKF2kg1GXdbFL8PBOn0WnL/x3n0pfEBPsEYigrZKJP2HpaL8J4bIOtXanfJoS1 I26LEWSiBilH/JCzX7NrkW0eDjoNRi459XDlqdS8yJze0KQzUEg8GL/YEi1XjWKBjNnr 3jVP1Rqdy3TG5UWpfEJ5LBfz5GY6Ut+VMrhcgl5Xi0VwzS2uMKmgXxuT2ay0VmRqMdQL ATJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=sV7vlp9vVqtESovTZq4J4qUrClPc07IPwMZZmtZmWxI=; b=1QOzLEvePWfSfuKJVn/I8V3bz2CSVLDZD9J7Pv4G/sOU0e7reXrt59UnlIak/k9ASm NoLcSHT0by9d+xQgJ9Im/WaZ+x6A0ONjBgEw4dI2+IXr2FbzV1VfWlPdneSzRII9AnXC S7bMGpTDhggF51+4ShAN6meDoh6Psvdt2tlaPczhdG65XkTlpN+H+1KXVhiUIFGkv0Ul WxVIEE1wmmuKqkIaizcreV+OShLx3jxMWH2lPZtOdnAXOwqU3ko31l+U0vEvkAuVOfHG NlIgIRalu9+H4tZM6myNlH/INM+Oj3VZYpOBCTnrTFdVRwvYraCy784Le+J0MITwTSqp K2YA== X-Gm-Message-State: ACgBeo1ALq63M3AH/ZUb8lzdVwR1O/Yp8yibqlIQPdeKcOpqeO2+Cxm3 v6vpeHE0kVpWGVjpGn+JyXxU3bW4wbSzGQ== X-Google-Smtp-Source: AA6agR7VqNHniSYB22eSZRdF7z3geWw36RASKr2qdfYIecjIbXQT5983ohhl0dn3RY3r/bg/tonT5g== X-Received: by 2002:a65:6556:0:b0:41c:9c36:98fa with SMTP id a22-20020a656556000000b0041c9c3698famr3287755pgw.491.1659651468390; Thu, 04 Aug 2022 15:17:48 -0700 (PDT) Received: from smtpclient.apple (c-24-6-216-183.hsd1.ca.comcast.net. [24.6.216.183]) by smtp.gmail.com with ESMTPSA id z1-20020a170903018100b0016f0d6213a5sm1527879plg.2.2022.08.04.15.17.45 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Aug 2022 15:17:46 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.1\)) Subject: Re: [PATCH v2 0/2] mm: Remember a/d bits for migration entries From: Nadav Amit In-Reply-To: <20220804203952.53665-1-peterx@redhat.com> Date: Thu, 4 Aug 2022 15:17:44 -0700 Cc: Linux MM , LKML , Huang Ying , Andrea Arcangeli , David Hildenbrand , Minchan Kim , Andrew Morton , Vlastimil Babka , Hugh Dickins , Andi Kleen , "Kirill A . Shutemov" Content-Transfer-Encoding: 7bit Message-Id: <8FBBFD68-3315-48D6-B318-4AA5A170C0C8@gmail.com> References: <20220804203952.53665-1-peterx@redhat.com> To: Peter Xu X-Mailer: Apple Mail (2.3696.120.41.1.1) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Aug 4, 2022, at 1:39 PM, Peter Xu wrote: > (1) Page Idle Tracking > > Before this series, idle tracking can cause false negative if an accessed > page got migrated, since after migration the young bit will get lost. > After this series, it'll be better in that after migration young bit will > be persisted, so it'll be able to be detected correctly by page idle > logic when walking the pgtable. > > However there's still nothing done when page idle reset was carried out > during migration procedure in progress, but that should be a separate > topic to be addressed (e.g. to teach rmap pgtable walk code to be able to > walk with both present ptes and migration ptes). IIUC, when a migration entry is set page_remove_rmap() is called by try_to_migrate_one(), so improving page-idle accuracy should be done in a different way.