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_PASS,URIBL_BLOCKED autolearn=ham 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 1DB10C43A1D for ; Thu, 12 Jul 2018 02:48:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D5DC321471 for ; Thu, 12 Jul 2018 02:48:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D5DC321471 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726575AbeGLCzT (ORCPT ); Wed, 11 Jul 2018 22:55:19 -0400 Received: from mga03.intel.com ([134.134.136.65]:44203 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726394AbeGLCzT (ORCPT ); Wed, 11 Jul 2018 22:55:19 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Jul 2018 19:48:00 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,341,1526367600"; d="scan'208";a="54394119" Received: from unknown (HELO [10.239.13.97]) ([10.239.13.97]) by fmsmga008.fm.intel.com with ESMTP; 11 Jul 2018 19:47:58 -0700 Message-ID: <5B46C258.40601@intel.com> Date: Thu, 12 Jul 2018 10:52:08 +0800 From: Wei Wang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Linus Torvalds CC: Michal Hocko , virtio-dev@lists.oasis-open.org, Linux Kernel Mailing List , virtualization , KVM list , linux-mm , "Michael S. Tsirkin" , Andrew Morton , Paolo Bonzini , liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu0@gmail.com, nilal@redhat.com, Rik van Riel , peterx@redhat.com Subject: Re: [PATCH v35 1/5] mm: support to get hints of free page blocks References: <1531215067-35472-1-git-send-email-wei.w.wang@intel.com> <1531215067-35472-2-git-send-email-wei.w.wang@intel.com> <5B455D50.90902@intel.com> <20180711092152.GE20050@dhcp22.suse.cz> <5B46BB46.2080802@intel.com> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/12/2018 10:30 AM, Linus Torvalds wrote: > On Wed, Jul 11, 2018 at 7:17 PM Wei Wang wrote: >> Would it be better to remove __GFP_THISNODE? We actually want to get all >> the guest free pages (from all the nodes). > Maybe. Or maybe it would be better to have the memory balloon logic be > per-node? Maybe you don't want to remove too much memory from one > node? I think it's one of those "play with it" things. > > I don't think that's the big issue, actually. I think the real issue > is how to react quickly and gracefully to "oops, I'm trying to give > memory away, but now the guest wants it back" while you're in the > middle of trying to create that 2TB list of pages. OK. virtio-balloon has already registered an oom notifier (virtballoon_oom_notify). I plan to add some control there. If oom happens, - stop the page allocation; - immediately give back the allocated pages to mm. Best, Wei