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=-4.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 01310C433E6 for ; Wed, 10 Feb 2021 15:59:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AED6664DE9 for ; Wed, 10 Feb 2021 15:59:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232009AbhBJP7v (ORCPT ); Wed, 10 Feb 2021 10:59:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60850 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231984AbhBJP7c (ORCPT ); Wed, 10 Feb 2021 10:59:32 -0500 Received: from mail-pf1-x435.google.com (mail-pf1-x435.google.com [IPv6:2607:f8b0:4864:20::435]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0A93C061574 for ; Wed, 10 Feb 2021 07:58:51 -0800 (PST) Received: by mail-pf1-x435.google.com with SMTP id c11so1517035pfp.10 for ; Wed, 10 Feb 2021 07:58:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=1A2lhIKvKlS4fQMuHUtKegN4NAsMUDtsHg94t+brQEQ=; b=fZxQazPUhZs9+BFdJj9CbxH0PeQgY68peDCuNO5Mu/dzJ+swkj2/ojoJMtuLnaW/2m XofRSvc8KoONaWfgXnR62zjiOc31KCWmJkP8AhzLH2NB11cVQpZ1D7VN37HslidVC8V1 SGVlqvgsf0OlVvOBaejkjd/EXyL1v61QDZdRe+d6pMCVTcFvLlv3IrdaKPoI8DmKuD1b x7KmU5MlRPlezmXMOmrn/OD+V18+neit6xmafnfgEEEDQ20N5Abivp8eHVmCV9DDgxwP SLp7Y0OgMd/c/Mx+ZsD3IDzlXl2PJS5OQHrPuJBPrQTbRdwSeQ6GhpjchkKs1FcqU9Sb kVDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=1A2lhIKvKlS4fQMuHUtKegN4NAsMUDtsHg94t+brQEQ=; b=nz+y1g6EHlYJoosAJLhpTCdqMvYKdXN6qncEcqbX0D2SqnRjGor65Uksy8BrMfjjN5 9ZwW7x79Rfp44TlLwZir8pm/evd7NYJcAbCowfUMnjoqjXUKDFSabxjCEjVEoAHUd9Wv sxrbsYJJJpsxXGZ5Mduu0ma21kkQBgMXgBf2tydckjMayL+8CdnxeWu0kNDKGRmUJoih uvRslpbTEZQbKunk9jXuQu3BYergS5dJgSGnV9Uwk5KurzjfA9k4+xtpNPrk0FV/JMGj IhPx3PZ4/lJK6Sg/u2WoazPWXs8srkK1cH+DuJPCpz4KLmxLPYBjt+IMG++BWGL8pc5A dGJg== X-Gm-Message-State: AOAM533i5cU7wsgFQrZgzVfwCDOzA3cocH/rCfRVS5rDvUBz3M2rjGkC JzYrhonhc17h8EyCNHrJ474= X-Google-Smtp-Source: ABdhPJwhBFqQ0/l2Rds/W6FK0eJuRZmRnVHZ1WS6rH3ONPiLKneNGesm0Z3TZZHWOXq6D1HfJuxFOw== X-Received: by 2002:a62:a214:0:b029:1d8:d104:6a2 with SMTP id m20-20020a62a2140000b02901d8d10406a2mr3689377pff.36.1612972731396; Wed, 10 Feb 2021 07:58:51 -0800 (PST) Received: from google.com ([2620:15c:211:201:e5b0:be96:1dfb:a1f6]) by smtp.gmail.com with ESMTPSA id q2sm2431299pfu.215.2021.02.10.07.58.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Feb 2021 07:58:50 -0800 (PST) Sender: Minchan Kim Date: Wed, 10 Feb 2021 07:58:48 -0800 From: Minchan Kim To: Vlastimil Babka Cc: Oscar Salvador , David Hildenbrand , Andrew Morton , linux-mm , LKML , Michal Hocko Subject: Re: [PATCH] mm: remove lru_add_drain_all in alloc_contig_range Message-ID: References: <20210209175048.361638-1-minchan@kernel.org> <20210209190332.GA3363@localhost.localdomain> <49491777-6d61-db4d-5e90-7a8b9045faca@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49491777-6d61-db4d-5e90-7a8b9045faca@suse.cz> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 10, 2021 at 01:17:33PM +0100, Vlastimil Babka wrote: > On 2/9/21 8:03 PM, Oscar Salvador wrote: > > On Tue, Feb 09, 2021 at 07:17:59PM +0100, David Hildenbrand wrote: > >> I was expecting some magical reason why this is still required but I am not > >> able to find a compelling one. Maybe this is really some historical > >> artifact. > >> > >> Let's see if other people know why this call here still exists. > > > > I also stumbled upon this while working on adding hugetlb support for > > alloc_acontig_range [1]. > > I have to confess I puzzled me a bit. > > > > I saw it going back to when the function was first introduced by > > > > commit 041d3a8cdc18dc375a128d90bbb753949a81b1fb > > Author: Michal Nazarewicz > > Date: Thu Dec 29 13:09:50 2011 +0100 > > > > mm: page_alloc: introduce alloc_contig_range() > > > > > > It does not make much sense to me. At this point our pages are free, so > > we do not care about LRU handling here. > > But I might be missing something. > > AFAICS, at the time page migration used putback_lru_page() to release the > migration source page. This would put the page on lru pvec even if it was in > fact not mapped anywhere anymore, and only the drain would actually free it. > Seems Minchan optimized this in 2016 by c6c919eb90e0 ("mm: use put_page() to > free page instead of putback_lru_page()") > > > [1] https://lore.kernel.org/linux-mm/20210208103935.GA32103@linux/T/#md651fc6e73c656105179382f92f8b2d6073051d1 Thanks for digging history, Vlastimil!