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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 30BC7C2D0F2 for ; Wed, 1 Apr 2020 08:31:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA7562078B for ; Wed, 1 Apr 2020 08:31:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585729910; bh=SosAPIgty62arZjGRGAxn9l2VAMh2Nt8knVNSWRc2Ro=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=BfS0yOL4MCNJqTydEd8oRMhhSwylbnjunXdaElNPsxG6IkPGvVGzLKGr5H7jj1f7a gBF3E0E4qspoAysVy46Wz4Vmutu4BFmgVCV1sw33YeeFXx05lTNGg3zB+7EzBCS7jP 6QURGUVHx2tgN4svMKHRTIhziareDDyWD1oA7NmE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731339AbgDAIbt (ORCPT ); Wed, 1 Apr 2020 04:31:49 -0400 Received: from mail-wm1-f67.google.com ([209.85.128.67]:40352 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726197AbgDAIbs (ORCPT ); Wed, 1 Apr 2020 04:31:48 -0400 Received: by mail-wm1-f67.google.com with SMTP id a81so6129251wmf.5 for ; Wed, 01 Apr 2020 01:31:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=WVdUIRS1ycLvk6rcBuIPpHGovPPX241fTsOlQTbUJ+g=; b=FYF+3GGFE9+703iuOEHH4UJTPws9kugHBbHMtw5M7AKyr0eoYbU8QvuklSpHn0LEha TGOSLeFRRuGu/ftxViX7Phv29V1YZhkHtmR7y0Gf6uYxhe5nxQTuhV/c8OUpNZMpv/eW nnHA2onQecsqdfhkQelr/nAAu2xpkKWRzwJE+fZzhmUgdU2SgFS8azLeGZJzjMiHNVxJ xni+Hnh4KAQDPxSgf0dEY1VhTJsMUMEIjCP1HjtZu38ryyNigen51GAYJn3tnMhM1Tu7 Z5MLiEeGmAEkWc9BcAJSmQJQ3sIxp7Xn9Vp9pMzriXFAB9Ct3Epj2uAbQ2ldffwZCCd3 FLzw== X-Gm-Message-State: AGi0PuawOfeYdvVgN0M5SaLehtr/rgY4focameafy320zKfNX6JNFqBX g+irwI0dBVfW8UqLrSntTew= X-Google-Smtp-Source: APiQypLCzLi28uZ9bahmO7Z3PVZGhnTzNbaVcCbmHy+m/fBgPgeXw3iorTSbzaO9gBIS13y1kYck6w== X-Received: by 2002:a7b:c145:: with SMTP id z5mr3097856wmi.55.1585729907100; Wed, 01 Apr 2020 01:31:47 -0700 (PDT) Received: from localhost (ip-37-188-180-223.eurotel.cz. [37.188.180.223]) by smtp.gmail.com with ESMTPSA id j188sm1722851wmj.36.2020.04.01.01.31.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Apr 2020 01:31:46 -0700 (PDT) Date: Wed, 1 Apr 2020 10:31:45 +0200 From: Michal Hocko To: "Huang, Ying" Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Minchan Kim , Hugh Dickins , Rik van Riel Subject: Re: [PATCH] mm, trivial: Simplify swap related code in try_to_unmap_one() Message-ID: <20200401083145.GF22681@dhcp22.suse.cz> References: <20200331084613.1258555-1-ying.huang@intel.com> <20200331094108.GF30449@dhcp22.suse.cz> <87tv24j9hq.fsf@yhuang-dev.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87tv24j9hq.fsf@yhuang-dev.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. -- Michal Hocko SUSE Labs