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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable 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 A4DBCC10F0E for ; Tue, 9 Apr 2019 13:38:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E2D52064B for ; Tue, 9 Apr 2019 13:38:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727178AbfDINh7 (ORCPT ); Tue, 9 Apr 2019 09:37:59 -0400 Received: from mail-qk1-f196.google.com ([209.85.222.196]:33482 "EHLO mail-qk1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726711AbfDINh6 (ORCPT ); Tue, 9 Apr 2019 09:37:58 -0400 Received: by mail-qk1-f196.google.com with SMTP id k189so10250219qkc.0 for ; Tue, 09 Apr 2019 06:37:58 -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=NrH0wRjSc274UknaC3QIC9X+7Oupxwsgd4xWd2VOIbE=; b=ZyVADLrIpw536/Gnl0DuDk/tDbVSR6nx1MpOnDo/ECHpOUi/m5qGK88XZ1dNKH+P2m MGMxsB9Yx9Zf6fK5o87Fw1pvBGnfq8yH6hsi+GNGyVfBSm1CaqACGjx8nbyV36vzq8ku O24x4aQNhvp0ObC9xFqAB2ZpFp2Ux1U/XDxez46A7iiBPrMPIm2PHQflDv/1prsohVLd 5zBKX2FrKOK+yApqZxnjDG9aqxyYvpiUT5HnFQa7/YUh7oh8CxX521JdcpbfnDQ0+0RQ 527hR2/DA89oRODUhO/qAzt4PpOhg+IYvo7fiqlMuTLVKiLYh84UOnEH1kvm3wmVxJ3I MkMQ== X-Gm-Message-State: APjAAAWNnn2pHejcm979VISwcN+sGqhPt3RZXZT9LLoy4Q18hichoJZ1 rw6uk2ZkED9a2izd+3dzH0Hm6338buw= X-Google-Smtp-Source: APXvYqz0P59G4x2QFXgYvEOPGfKQvp0965gG/JLcggQUBLhwcwZLsi2c+wfUIMH4hZuN9U4Kbzx3ew== X-Received: by 2002:a05:620a:15e7:: with SMTP id p7mr26856717qkm.283.1554817077928; Tue, 09 Apr 2019 06:37:57 -0700 (PDT) Received: from redhat.com (pool-173-76-246-42.bstnma.fios.verizon.net. [173.76.246.42]) by smtp.gmail.com with ESMTPSA id v4sm17179402qtq.94.2019.04.09.06.37.56 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 09 Apr 2019 06:37:57 -0700 (PDT) Date: Tue, 9 Apr 2019 09:37:54 -0400 From: "Michael S. Tsirkin" To: David Hildenbrand Cc: Alexander Duyck , Nitesh Narayan Lal , kvm list , LKML , linux-mm , Paolo Bonzini , lcapitulino@redhat.com, pagupta@redhat.com, wei.w.wang@intel.com, Yang Zhang , Rik van Riel , dodgen@google.com, Konrad Rzeszutek Wilk , dhildenb@redhat.com, Andrea Arcangeli Subject: Re: Thoughts on simple scanner approach for free page hinting Message-ID: <20190409093642-mutt-send-email-mst@kernel.org> References: <20190409092625-mutt-send-email-mst@kernel.org> <43aa1bd2-4aac-5ac4-3bd4-fe1e4a342c79@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43aa1bd2-4aac-5ac4-3bd4-fe1e4a342c79@redhat.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Apr 09, 2019 at 03:36:08PM +0200, David Hildenbrand wrote: > On 09.04.19 15:31, Michael S. Tsirkin wrote: > > On Tue, Apr 09, 2019 at 11:20:36AM +0200, David Hildenbrand wrote: > >> BTW I like the idea of allocating pages that have already been hinted as > >> last "choice", allocating pages that have not been hinted yet first. > > > > OK I guess but note this is just a small window during which > > not all pages have been hinted. > > Yes, good point. It might sound desirable but might be completely > irrelevant in practice. > > > > > So if we actually think this has value then we need > > to design something that will desist and not drop pages > > in steady state too. > > By dropping, you mean dropping hints of e.g. MAX_ORDER - 1 or e.g. not > reporting MAX_ORDER - 3? I mean the issue is host unmaps the pages from guest right? That is what makes hinted pages slower than non-hinted ones. If we do not want that to happen for some pages, then either host can defer acting on the hint, or we can defer hinting. > -- > > Thanks, > > David / dhildenb