Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752521AbaJPUhZ (ORCPT ); Thu, 16 Oct 2014 16:37:25 -0400 Received: from mail-pd0-f176.google.com ([209.85.192.176]:46815 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751369AbaJPUhX (ORCPT ); Thu, 16 Oct 2014 16:37:23 -0400 Date: Thu, 16 Oct 2014 13:37:19 -0700 From: Dmitry Torokhov To: David Vrabel Cc: hansechang@gmail.com, linux-kernel@vger.kernel.org, xen-devel@lists.xen.org, Chang Huaixin , jinsong.liu@alibaba-inc.com, Ian.Campbell@eu.citrix.com, dgdegra@tycho.nsa.gov, boris.ostrovsky@oracle.com Subject: Re: [Xen-devel] [PATCH] Input: xen-kbdfront - free grant table entry in xenkbd_disconnect_backend Message-ID: <20141016203719.GB38361@dtor-ws> References: <1413423992-3005-1-git-send-email-hansechang@gmail.com> <543FEBC5.2050202@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <543FEBC5.2050202@citrix.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 16, 2014 at 05:01:09PM +0100, David Vrabel wrote: > On 16/10/14 02:46, hansechang@gmail.com wrote: > > From: Chang Huaixin > > > > xenkbd_disconnect_backend doesn't free grant table entry. > > This bug affects live migration. > > > > xenkbd_disconnect_backend uses gnttab_end_foreign_access_ref > > to handle grant table entry which doesn't really free an entry. > > > > Thus every time we do xenkbd_resume, grant table entry increses > > by one. As an grant table entry occupies 8 bytes, an grant table > > page has at most 512 entries. Every 512 times we do xenkdb_resume, > > grant table pages increses by one. > > > > After around 3500 times of live migration, grant table pages > > will increase by 7, causing too many pages to populate and hitting > > max_pages limit when assigning pages.Thus assign_pages will fail, > > so will live migration. > > Acked-by: David Vrabel > > This need to be send to the input subsystem maintainers. Applied, thank you. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/