From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753763Ab1HHHb5 (ORCPT ); Mon, 8 Aug 2011 03:31:57 -0400 Received: from mail-pz0-f42.google.com ([209.85.210.42]:48265 "EHLO mail-pz0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753176Ab1HHHb4 (ORCPT ); Mon, 8 Aug 2011 03:31:56 -0400 Message-ID: <4E3F90E3.9080600@gmail.com> Date: Mon, 08 Aug 2011 15:31:47 +0800 From: Liu Yuan User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.18) Gecko/20110617 Thunderbird/3.1.11 MIME-Version: 1.0 To: Badari Pulavarty CC: Stefan Hajnoczi , "Michael S. Tsirkin" , Rusty Russell , Avi Kivity , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Khoa Huynh Subject: Re: [RFC PATCH]vhost-blk: In-kernel accelerator for virtio block device References: <1311863346-4338-1-git-send-email-namei.unix@gmail.com> <4E325F98.5090308@gmail.com> <4E32F7F2.4080607@us.ibm.com> <4E363DB9.70801@gmail.com> <1312495132.9603.4.camel@badari-desktop> <4E3BCE4D.7090809@gmail.com> <4E3C302A.3040500@us.ibm.com> <4E3F3D4E.70104@gmail.com> <4E3F6E72.1000907@us.ibm.com> In-Reply-To: <4E3F6E72.1000907@us.ibm.com> Content-Type: multipart/mixed; boundary="------------040907030002040109090908" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------040907030002040109090908 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit On 08/08/2011 01:04 PM, Badari Pulavarty wrote: > On 8/7/2011 6:35 PM, Liu Yuan wrote: >> On 08/06/2011 02:02 AM, Badari Pulavarty wrote: >>> On 8/5/2011 4:04 AM, Liu Yuan wrote: >>>> On 08/05/2011 05:58 AM, Badari Pulavarty wrote: >>>>> Hi Liu Yuan, >>>>> >>>>> I started testing your patches. I applied your kernel patch to 3.0 >>>>> and applied QEMU to latest git. >>>>> >>>>> I passed 6 blockdevices from the host to guest (4 vcpu, 4GB RAM). >>>>> I ran simple "dd" read tests from the guest on all block devices >>>>> (with various blocksizes, iflag=direct). >>>>> >>>>> Unfortunately, system doesn't stay up. I immediately get into >>>>> panic on the host. I didn't get time to debug the problem. Wondering >>>>> if you have seen this issue before and/or you have new patchset >>>>> to try ? >>>>> >>>>> Let me know. >>>>> >>>>> Thanks, >>>>> Badari >>>>> >>>> >>>> Okay, it is actually a bug pointed out by MST on the other thread, >>>> that it needs a mutex for completion thread. >>>> >>>> Now would you please this attachment?This patch only applies to >>>> kernel part, on top of v1 kernel patch. >>>> >>>> This patch mainly moves completion thread into vhost thread as a >>>> function. As a result, both requests submitting and completion >>>> signalling is in the same thread. >>>> >>>> Yuan >>> >>> Unfortunately, "dd" tests (4 out of 6) in the guest hung. I see >>> following messages >>> >>> virtio_blk virtio2: requests: id 0 is not a head ! >>> virtio_blk virtio3: requests: id 1 is not a head ! >>> virtio_blk virtio5: requests: id 1 is not a head ! >>> virtio_blk virtio1: requests: id 1 is not a head ! >>> >>> I still see host panics. I will collect the host panic and see if >>> its still same or not. >>> >>> Thanks, >>> Badari >>> >>> >> Would you please show me how to reproduce it step by step? I tried dd >> with two block device attached, but didn't get hung nor panic. >> >> Yuan > > I did 6 "dd"s on 6 block devices.. > > dd if=/dev/vdb of=/dev/null bs=1M iflag=direct & > dd if=/dev/vdc of=/dev/null bs=1M iflag=direct & > dd if=/dev/vdd of=/dev/null bs=1M iflag=direct & > dd if=/dev/vde of=/dev/null bs=1M iflag=direct & > dd if=/dev/vdf of=/dev/null bs=1M iflag=direct & > dd if=/dev/vdg of=/dev/null bs=1M iflag=direct & > > I can reproduce the problem with in 3 minutes :( > > Thanks, > Badari > > Ah...I made an embarrassing mistake that I tried to 'free()' an kmem_cache object. Would you please revert the vblk-for-kernel-2 patch and apply the new one attached in this letter? Yuan, Thanks --------------040907030002040109090908 Content-Type: text/x-patch; name="vblk-for-kernel-2.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="vblk-for-kernel-2.patch" diff --git a/drivers/vhost/blk.c b/drivers/vhost/blk.c index ecaf6fe..7a24aba 100644 --- a/drivers/vhost/blk.c +++ b/drivers/vhost/blk.c @@ -47,6 +47,7 @@ struct vhost_blk { struct eventfd_ctx *ectx; struct file *efile; struct task_struct *worker; + struct vhost_poll poll; }; struct used_info { @@ -62,6 +63,7 @@ static struct kmem_cache *used_info_cachep; static void blk_flush(struct vhost_blk *blk) { vhost_poll_flush(&blk->vq.poll); + vhost_poll_flush(&blk->poll); } static long blk_set_features(struct vhost_blk *blk, u64 features) @@ -146,11 +148,11 @@ static long blk_reset_owner(struct vhost_blk *b) blk_stop(b); blk_flush(b); ret = vhost_dev_reset_owner(&b->dev); - if (b->worker) { - b->should_stop = 1; - smp_mb(); - eventfd_signal(b->ectx, 1); - } +// if (b->worker) { +// b->should_stop = 1; +// smp_mb(); +// eventfd_signal(b->ectx, 1); +// } err: mutex_unlock(&b->dev.mutex); return ret; @@ -361,8 +363,8 @@ static long vhost_blk_ioctl(struct file *f, unsigned int ioctl, default: mutex_lock(&blk->dev.mutex); ret = vhost_dev_ioctl(&blk->dev, ioctl, arg); - if (!ret && ioctl == VHOST_SET_OWNER) - ret = blk_set_owner(blk); +// if (!ret && ioctl == VHOST_SET_OWNER) +// ret = blk_set_owner(blk); blk_flush(blk); mutex_unlock(&blk->dev.mutex); break; @@ -480,10 +482,50 @@ static void handle_guest_kick(struct vhost_work *work) handle_kick(blk); } +static void handle_completetion(struct vhost_work* work) +{ + struct vhost_blk *blk = container_of(work, struct vhost_blk, poll.work); + struct timespec ts = { 0 }; + int ret, i, nr; + u64 count; + + do { + ret = eventfd_ctx_read(blk->ectx, 1, &count); + } while (unlikely(ret == -ERESTARTSYS)); + + do { + nr = kernel_read_events(blk->ioctx, count, MAX_EVENTS, events, &ts); + } while (unlikely(nr == -EINTR)); + dprintk("%s, count %llu, nr %d\n", __func__, count, nr); + + if (unlikely(nr <= 0)) + return; + + for (i = 0; i < nr; i++) { + struct used_info *u = (struct used_info *)events[i].obj; + int len, status; + + dprintk("%s, head %d complete in %d\n", __func__, u->head, i); + len = io_event_ret(&events[i]); + //status = u->len == len ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR; + status = len > 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR; + if (copy_to_user(u->status, &status, sizeof status)) { + vq_err(&blk->vq, "%s failed to write status\n", __func__); + BUG(); /* FIXME: maybe a bit radical? */ + } + vhost_add_used(&blk->vq, u->head, u->len); + kmem_cache_free(used_info_cachep, u); + } + + vhost_signal(&blk->dev, &blk->vq); +} + static void eventfd_setup(struct vhost_blk *blk) { blk->efile = eventfd_file_create(0, 0); blk->ectx = eventfd_ctx_fileget(blk->efile); + vhost_poll_init(&blk->poll, handle_completetion, POLLIN, &blk->dev); + vhost_poll_start(&blk->poll, blk->efile); } static int vhost_blk_open(struct inode *inode, struct file *f) @@ -528,7 +570,7 @@ static int vhost_blk_release(struct inode *inode, struct file *f) vhost_dev_cleanup(&blk->dev); /* Yet another flush? See comments in vhost_net_release() */ blk_flush(blk); - completion_thread_destory(blk); +// completion_thread_destory(blk); eventfd_destroy(blk); kfree(blk); --------------040907030002040109090908--