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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=unavailable 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 55146C43381 for ; Thu, 28 Feb 2019 18:37:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 337F9218AE for ; Thu, 28 Feb 2019 18:37:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388905AbfB1ShP (ORCPT ); Thu, 28 Feb 2019 13:37:15 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:36612 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387399AbfB1ShO (ORCPT ); Thu, 28 Feb 2019 13:37:14 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::bf5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 268FB14BA6D35; Thu, 28 Feb 2019 10:37:14 -0800 (PST) Date: Thu, 28 Feb 2019 10:37:13 -0800 (PST) Message-Id: <20190228.103713.745079321072396223.davem@davemloft.net> To: igor.druzhinin@citrix.com Cc: xen-devel@lists.xenproject.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, wei.liu2@citrix.com, paul.durrant@citrix.com Subject: Re: [PATCH v2] xen-netback: fix occasional leak of grant ref mappings under memory pressure From: David Miller In-Reply-To: <1551358083-14227-1-git-send-email-igor.druzhinin@citrix.com> References: <1551358083-14227-1-git-send-email-igor.druzhinin@citrix.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 28 Feb 2019 10:37:14 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Igor Druzhinin Date: Thu, 28 Feb 2019 12:48:03 +0000 > Zero-copy callback flag is not yet set on frag list skb at the moment > xenvif_handle_frag_list() returns -ENOMEM. This eventually results in > leaking grant ref mappings since xenvif_zerocopy_callback() is never > called for these fragments. Those eventually build up and cause Xen > to kill Dom0 as the slots get reused for new mappings: > > "d0v0 Attempt to implicitly unmap a granted PTE c010000329fce005" > > That behavior is observed under certain workloads where sudden spikes > of page cache writes coexist with active atomic skb allocations from > network traffic. Additionally, rework the logic to deal with frag_list > deallocation in a single place. > > Signed-off-by: Paul Durrant > Signed-off-by: Igor Druzhinin Applied and queued up for -stable, thanks.