From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39826) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VZH00-0006A6-3K for qemu-devel@nongnu.org; Thu, 24 Oct 2013 05:14:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VZGzr-00046P-N9 for qemu-devel@nongnu.org; Thu, 24 Oct 2013 05:14:36 -0400 Received: from mail-we0-x235.google.com ([2a00:1450:400c:c03::235]:38937) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VZGzr-00045x-HA for qemu-devel@nongnu.org; Thu, 24 Oct 2013 05:14:27 -0400 Received: by mail-we0-f181.google.com with SMTP id t60so2032223wes.12 for ; Thu, 24 Oct 2013 02:14:26 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <5268E4EF.3090007@redhat.com> Date: Thu, 24 Oct 2013 10:14:23 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1382599289-9503-1-git-send-email-pl@kamp.de> In-Reply-To: <1382599289-9503-1-git-send-email-pl@kamp.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RESEND][PATCH 1.7] migration: drop MADVISE_DONT_NEED for incoming zero pages List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven Cc: haoyu.zhang@huawei.com, xiaoguangrong@linux.vnet.ibm.com, qemu-devel@nongnu.org, afaerber@suse.de, quintela@redhat.com Il 24/10/2013 08:21, Peter Lieven ha scritto: > Additionally we memmap target memory so it is essentially > zero initialized (except for e.g. option roms and bios which are loaded > into target memory although they shouldn't). > > It was reported recently that this madvise causes a performance degradation > in some situations. As the madvise should only be called rarely and if it's called > it is likely on a busy page (it was non-zero and changed to zero during migration) > drop it completely. Tagging this patch for 1.7. Paolo