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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C157BC43331 for ; Wed, 1 Apr 2020 08:48:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 98E98215A4 for ; Wed, 1 Apr 2020 08:48:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 98E98215A4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 49A936B00AD; Wed, 1 Apr 2020 04:48:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 421116B00AE; Wed, 1 Apr 2020 04:48:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 274116B00AF; Wed, 1 Apr 2020 04:48:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0080.hostedemail.com [216.40.44.80]) by kanga.kvack.org (Postfix) with ESMTP id 0F2D46B00AD for ; Wed, 1 Apr 2020 04:48:32 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id CCB924DDC for ; Wed, 1 Apr 2020 08:48:31 +0000 (UTC) X-FDA: 76658660022.28.truck57_8497c82c65b40 X-HE-Tag: truck57_8497c82c65b40 X-Filterd-Recvd-Size: 2247 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by imf20.hostedemail.com (Postfix) with ESMTP for ; Wed, 1 Apr 2020 08:48:30 +0000 (UTC) IronPort-SDR: w8VObnwrp64CXqGkJJxKBHpamq7rhgPNwEuvx81JUajmevORVjLjU3XUUUf29F7o3nMrQVS1Fj BHKrNX+nXCRA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Apr 2020 01:48:28 -0700 IronPort-SDR: +kD+1LPObTnDW+tjrDY8ZK6ifmKOtSQjFurJiHpJ92L5wdLV1NklAlEmViRVCAclUsOX0wwzvy LRNSi/vHiihg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,331,1580803200"; d="scan'208";a="295263752" Received: from yhuang-dev.sh.intel.com (HELO yhuang-dev) ([10.239.159.23]) by FMSMGA003.fm.intel.com with ESMTP; 01 Apr 2020 01:48:27 -0700 From: "Huang\, Ying" To: Michal Hocko Cc: Andrew Morton , , , Minchan Kim , "Hugh Dickins" , Rik van Riel Subject: Re: [PATCH] mm, trivial: Simplify swap related code in try_to_unmap_one() References: <20200331084613.1258555-1-ying.huang@intel.com> <20200331094108.GF30449@dhcp22.suse.cz> <87tv24j9hq.fsf@yhuang-dev.intel.com> <20200401083145.GF22681@dhcp22.suse.cz> Date: Wed, 01 Apr 2020 16:48:27 +0800 In-Reply-To: <20200401083145.GF22681@dhcp22.suse.cz> (Michal Hocko's message of "Wed, 1 Apr 2020 10:31:45 +0200") Message-ID: <87tv23h9r8.fsf@yhuang-dev.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Michal Hocko writes: > On Wed 01-04-20 09:11:13, Huang, Ying wrote: > [...] >> Then what is the check !PageSwapBacked() && PageSwapCache() for? To >> prevent someone to change the definition of PageSwapCache() in the >> future to break this? > > Yes this is my understading. It is essentially an assert that enforces > the assumption about swap cache vs. swap backed being coupled. OK. Then we can just keep the current code. Best Regards, Huang, Ying