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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 341E7C433FE for ; Fri, 4 Dec 2020 17:51:35 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B6DDB22B40 for ; Fri, 4 Dec 2020 17:51:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B6DDB22B40 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=soleen.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 48D2B6B006E; Fri, 4 Dec 2020 12:51:34 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 415D56B0070; Fri, 4 Dec 2020 12:51:34 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2DE896B0071; Fri, 4 Dec 2020 12:51:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0228.hostedemail.com [216.40.44.228]) by kanga.kvack.org (Postfix) with ESMTP id 0DA1A6B006E for ; Fri, 4 Dec 2020 12:51:34 -0500 (EST) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id B8051181AC9CC for ; Fri, 4 Dec 2020 17:51:33 +0000 (UTC) X-FDA: 77556342066.25.angle86_4901260273c6 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 8DB221804E3A0 for ; Fri, 4 Dec 2020 17:51:33 +0000 (UTC) X-HE-Tag: angle86_4901260273c6 X-Filterd-Recvd-Size: 4500 Received: from mail-ej1-f65.google.com (mail-ej1-f65.google.com [209.85.218.65]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Fri, 4 Dec 2020 17:51:32 +0000 (UTC) Received: by mail-ej1-f65.google.com with SMTP id lt17so9931691ejb.3 for ; Fri, 04 Dec 2020 09:51:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=31hFFArVFLayAbe984Eq857Ijkymag2EX547dIYCVVI=; b=BrJgrP7Vo3LsmjP4/uK2WLmNtvnlKQyJEgcHA5V4T3luCMqNP3fshfXe3HuzodHt6N JSLH3JnZlJTHfVDwCtHwD2/CTz2RYeTVdOrgd2tziEliPzMWNRwdbC+1cYlekpPqoDCP Im+3pT9EMLVmgyto13Vn0baiJoH2KNA9WJHLqX+0JKEkZNiVhHVuyFjkhVCyeio42C6V 1mIpkLUflzsJLCB/dzLd1YjC9x4tYWkJejs/98rtk762W2VNuIvdWnwZh2qZbNGF6khU ASF4BNQnqx/5CYt4fw5dzqAKRDmqMpkNDMBFs9ZvXvqHELGFEyjqBJxY2cp4a6VIhqGj g7WA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=31hFFArVFLayAbe984Eq857Ijkymag2EX547dIYCVVI=; b=oYQTJXzIE8wa+H2ksLLiK+VBpvdjtzRdRgoBj3MMV5vJ56VgHH5tfUiVcEL2veNzwT UVM6/QV7PSsQ1KqpnyDJUwQ6XdDtmNNPUm1IWoTG+CH+5ENUb19saQ5B+yzVzvXjMCFp Q3YnVXfczZLhAiW7qrZyKtDKo0+sT09gsPDB8R+9Y7Yb3FzHcwEeSrOkd7mhfzdrSrUG 6y550iziUcHwPiqJor0ELvTSwFa+/Dou9ZFBfFoMUeTG4Yt+mpHqehAemRbTliYf9ZMc ofxEE11CNc84LwnIY3mvUkMyxzNHAT/zJDGdPOTFrAgBxSUSeDtprNIPQJX9LQrDlFIZ isdg== X-Gm-Message-State: AOAM532gjqipPbJrgv1+Uaz8iIacx+4QGIU8/L+wDw9cx8G+iqfvj16o KjeKwBwoxcQQHlZUKehUfmaZgn//FRQR34x2GE29HA== X-Google-Smtp-Source: ABdhPJzQ5DmWTJPAXFIAqFmYUlq/WxtfwZmY+wOrx2ijrmExTi6caux3QODt6HEXqCy/qW7swrllDjZ5kKs2VzYYJBM= X-Received: by 2002:a17:906:fb9b:: with SMTP id lr27mr8443175ejb.175.1607104291943; Fri, 04 Dec 2020 09:51:31 -0800 (PST) MIME-Version: 1.0 References: <20201202052330.474592-1-pasha.tatashin@soleen.com> <20201204035953.GA17056@js1304-desktop> <20201204161005.GD5487@ziepe.ca> In-Reply-To: <20201204161005.GD5487@ziepe.ca> From: Pavel Tatashin Date: Fri, 4 Dec 2020 12:50:56 -0500 Message-ID: Subject: Re: [PATCH 0/6] prohibit pinning pages in ZONE_MOVABLE To: Jason Gunthorpe Cc: Joonsoo Kim , LKML , linux-mm , Andrew Morton , Vlastimil Babka , Michal Hocko , David Hildenbrand , Oscar Salvador , Dan Williams , Sasha Levin , Tyler Hicks , mike.kravetz@oracle.com, Steven Rostedt , Ingo Molnar , Peter Zijlstra , Mel Gorman , Matthew Wilcox , David Rientjes , John Hubbard Content-Type: text/plain; charset="UTF-8" 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: > > Yes, this indeed could be a problem for some configurations. I will > > add your comment to the commit log of one of the patches. > > It sounds like there is some inherent tension here, breaking THP's > when doing pin_user_pages() is a really nasty thing to do. DMA > benefits greatly from THP. > > I know nothing about ZONE_MOVABLE, is this auto-setup or an admin > option? If the result of this patch is standard systems can no longer > pin > 80% of their memory I have some regression concerns.. ZONE_MOVABLE can be configured via kernel parameter, or when memory nodes are onlined after hot-add; so this is something that admins configure. ZONE_MOVABLE is designed to gurantee memory hot-plug functionality, and not availability of THP, however, I did not know about the use case where some admins might configure ZONE_MOVABLE to increase availability of THP because pages are always migratable in them. The thing is, if we fragment ZONE_MOVABLE by pinning pages in it, the availability of THP also suffers. We can migrate pages in ZONE_NORMAL, just not guaranteed, so we can create THP in ZONE_NORMAL as well, which is the usual case.