From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751936AbdGaHnz (ORCPT ); Mon, 31 Jul 2017 03:43:55 -0400 Received: from mx2.suse.de ([195.135.220.15]:56594 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751822AbdGaHnx (ORCPT ); Mon, 31 Jul 2017 03:43:53 -0400 Date: Mon, 31 Jul 2017 09:43:50 +0200 From: Michal Hocko To: Wei Wang Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, virtualization@lists.linux-foundation.org, mst@redhat.com, mawilcox@microsoft.com, dave.hansen@intel.com, akpm@linux-foundation.org, zhenwei.pi@youruncloud.com Subject: Re: [PATCH] mm: don't zero ballooned pages Message-ID: <20170731074350.GC15767@dhcp22.suse.cz> References: <1501474413-21580-1-git-send-email-wei.w.wang@intel.com> <20170731065508.GE13036@dhcp22.suse.cz> <597EDF3D.8020101@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <597EDF3D.8020101@intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 31-07-17 15:41:49, Wei Wang wrote: > On 07/31/2017 02:55 PM, Michal Hocko wrote: > >On Mon 31-07-17 12:13:33, Wei Wang wrote: > >>Ballooned pages will be marked as MADV_DONTNEED by the hypervisor and > >>shouldn't be given to the host ksmd to scan. > >Could you point me where this MADV_DONTNEED is done, please? > > Sure. It's done in the hypervisor when the balloon pages are received. > > Please see line 40 at > https://github.com/qemu/qemu/blob/master/hw/virtio/virtio-balloon.c Thanks. Are all hypervisors which are using this API doing this? bb01b64cfab7 doesn't mention the specify hypervisor nor does it mention any real numbers so I suspect the revert is the right thing to do but the changelog should mention all those details. -- Michal Hocko SUSE Labs