From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH v3 0/5] xen/blk: persistent grant rework To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-block@vger.kernel.org, konrad.wilk@oracle.com, axboe@kernel.dk, boris.ostrovsky@oracle.com References: <20180813140114.20126-1-jgross@suse.com> <20180817155909.4cwiy6bhhgiala5m@mac> From: Juergen Gross Message-ID: <8aaf02b1-999d-81fc-2732-ed556b959a8a@suse.com> Date: Fri, 24 Aug 2018 15:52:23 +0200 MIME-Version: 1.0 In-Reply-To: <20180817155909.4cwiy6bhhgiala5m@mac> Content-Type: text/plain; charset=utf-8 List-ID: On 17/08/18 17:59, Roger Pau Monné wrote: > On Mon, Aug 13, 2018 at 04:01:09PM +0200, Juergen Gross wrote: >> Persistent grants are used in the Xen's blkfront/blkback drivers to >> avoid mapping/unmapping of I/O buffers in the backend for each I/O. >> >> While this speeds up processing quite a bit there are problems related >> to persistent grants in some configurations: domains with multiple >> block devices making use of persistent grants might suffer from a lack >> of grants if each of the block devices experienced a high I/O load at >> some time. This is due to the number of persistent grants per device >> only to be limited by a rather high maximum value, but never being >> released even in case of longer times without any I/O. >> >> This series modifies xen-blkback to unmap any domU page mapped via a >> persistent grant after a timeout (default: 60 seconds). The timeout >> is set to its default value again when a persistent grant has been >> used for an I/O. >> >> xen-blkfront is modified to scan every 10 seconds for persistent grants >> not in use by blkback any more and to remove such grants. >> >> The last 3 patches are small cleanups of blkfront and blkback drivers. >> >> V3: >> - patch 1: make timeout parameter static > > Konrad if you are OK with this series, could you please send a pull > request to Jens? Ping? Juergen