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=-3.8 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED autolearn=ham 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 6C375C43382 for ; Thu, 27 Sep 2018 14:26:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 236422152A for ; Thu, 27 Sep 2018 14:26:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="ByGzEMvs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 236422152A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728207AbeI0Uov (ORCPT ); Thu, 27 Sep 2018 16:44:51 -0400 Received: from mail-io1-f65.google.com ([209.85.166.65]:42791 "EHLO mail-io1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727320AbeI0Uov (ORCPT ); Thu, 27 Sep 2018 16:44:51 -0400 Received: by mail-io1-f65.google.com with SMTP id n18-v6so2066886ioa.9 for ; Thu, 27 Sep 2018 07:26:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=Jx/Yw2jAwCRr+817KCbU5DlwUdU/0vB+9VGXL3ZqI9c=; b=ByGzEMvsL8rR8IpG0SeGS0I57qBvj55a4WNy+e9kObpHnka4q7NaTuaMZZTiwqIbT2 Hf5UNGWrH/Q3C5tE0ANbPr2fX5QhpL+SuX5ko0X697T99pc09oZ/hWPWozuUaP2BAUuI OvTNG+gwGdGcJvxoUamAY7atADgE7vUP1J3nINVlfT3Icota7UcEu8mBR/zJsKRcWBIv jNHlXyvDj0rnO/90Zh9DyorcRkdi5s/zpmC0/kPX9gN/K63MOxRDrqss0tP9suErCOLi SHD7mauE0M94dAxpE7hxBVMMOx3RLme0GmgP3X4bIkCJgFs3XK9bRFU4gOyXcV0twpvI tX4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Jx/Yw2jAwCRr+817KCbU5DlwUdU/0vB+9VGXL3ZqI9c=; b=Y9y01PvveYtaGX0aV8DvsePeTPgrplvWTwykmAjMM+RXjL3QiaortBbh4DlNetbjm2 LvFnzYdl5j7EP05XEzRqAzOqm59zhzqSaY7WQMJVt4Cj1R97Thmkfgu8S6UoOyXeq/1p iHJAx4NcntTFwmy/m+Qr3jhDRIXAnVb7a2ueFNmPEIPWE6MVlIa0vxo/CdZfy6aN38Xh Zex7Fe0p72Sd60BJyir6smYntbBsZhoy8JlpetzcAXwgDd1C7KUmZBsTU6rKO/lz4WGi CeEh7Y8Tmr3HZFLIEWBXs08c5u9+wKE8gKtHU8w8TRAbXiycHWdzZBxHW+wgBbWH/xEs d/cA== X-Gm-Message-State: ABuFfoiB9VO73llAfRjbEUoYuBhSAfbyWL+kvVXm7ZZ/PfNi3xAON/+k SqyTzFtD4eaJ1M2MDwcOeD/tANh9PC8= X-Google-Smtp-Source: ACcGV60t+A0GUKDyzsNcWPD2IRpVgDCnCjrJtRRaXn9kmYDWPw3UkA/9ZI2j868G19weaGJi+uWsdw== X-Received: by 2002:a6b:7c4b:: with SMTP id b11-v6mr9219811ioq.251.1538058378709; Thu, 27 Sep 2018 07:26:18 -0700 (PDT) Received: from [192.168.1.56] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id b28-v6sm1161899itd.37.2018.09.27.07.26.17 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 Sep 2018 07:26:17 -0700 (PDT) Subject: Re: [PATCH] xen/blkfront: When purging persistent grants, keep them in the buffer To: Juergen Gross , Boris Ostrovsky , konrad.wilk@oracle.com, roger.pau@citrix.com Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org References: <20180922195549.27953-1-boris.ostrovsky@oracle.com> <28aa9249-7406-21c6-f509-65411828e2d7@suse.com> From: Jens Axboe Message-ID: <5bd1a695-50c6-e79f-38dd-c980fc2138ad@kernel.dk> Date: Thu, 27 Sep 2018 08:26:16 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: <28aa9249-7406-21c6-f509-65411828e2d7@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/27/18 1:12 AM, Juergen Gross wrote: > On 22/09/18 21:55, Boris Ostrovsky wrote: >> Commit a46b53672b2c ("xen/blkfront: cleanup stale persistent grants") >> added support for purging persistent grants when they are not in use. As >> part of the purge, the grants were removed from the grant buffer, This >> eventually causes the buffer to become empty, with BUG_ON triggered in >> get_free_grant(). This can be observed even on an idle system, within >> 20-30 minutes. >> >> We should keep the grants in the buffer when purging, and only free the >> grant ref. >> >> Fixes: a46b53672b2c ("xen/blkfront: cleanup stale persistent grants") >> Signed-off-by: Boris Ostrovsky > > Reviewed-by: Juergen Gross Since Konrad is out, I'm going to queue this up for 4.19. -- Jens Axboe