Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752050AbaJKIeJ (ORCPT ); Sat, 11 Oct 2014 04:34:09 -0400 Received: from mail-pd0-f174.google.com ([209.85.192.174]:63043 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751570AbaJKIeH (ORCPT ); Sat, 11 Oct 2014 04:34:07 -0400 From: hansechang@gmail.com To: linux-kernel@vger.kernel.org, xen-devel@lists.xen.org Cc: Ian.Campbell@eu.citrix.com, dgdegra@tycho.nsa.gov, jinsong.liu@alibaba-inc.com, Chang Huaixin Subject: [PATCH] Input: xen-kbdfront - free grant table entry in xenkbd_disconnect_backend Date: Sat, 11 Oct 2014 16:33:32 +0800 Message-Id: <1413016412-17890-1-git-send-email-hansechang@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Chang Huaixin --- drivers/input/misc/xen-kbdfront.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c index fbfdc10..e2ecfc6 100644 --- a/drivers/input/misc/xen-kbdfront.c +++ b/drivers/input/misc/xen-kbdfront.c @@ -285,7 +285,7 @@ static int xenkbd_connect_backend(struct xenbus_device *dev, error_evtchan: xenbus_free_evtchn(dev, evtchn); error_grant: - gnttab_end_foreign_access_ref(info->gref, 0); + gnttab_end_foreign_access(info->gref, 0, 0UL); info->gref = -1; return ret; } @@ -296,7 +296,7 @@ static void xenkbd_disconnect_backend(struct xenkbd_info *info) unbind_from_irqhandler(info->irq, info); info->irq = -1; if (info->gref >= 0) - gnttab_end_foreign_access_ref(info->gref, 0); + gnttab_end_foreign_access(info->gref, 0, 0UL); info->gref = -1; } -- 1.9.1 -- 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/