From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: "Xia, Chenbo" <chenbo.xia@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"david.marchand@redhat.com" <david.marchand@redhat.com>
Cc: "stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-stable] [PATCH v4 4/7] vhost: fix NUMA reallocation with multiqueue
Date: Fri, 18 Jun 2021 10:01:03 +0200 [thread overview]
Message-ID: <49426b63-82c8-230e-727f-91743657a471@redhat.com> (raw)
In-Reply-To: <MN2PR11MB40636E8EDB9519FDD9736CCB9C0D9@MN2PR11MB4063.namprd11.prod.outlook.com>
On 6/18/21 6:34 AM, Xia, Chenbo wrote:
> Hi Maxime,
>
>> -----Original Message-----
>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Sent: Thursday, June 17, 2021 11:38 PM
>> To: dev@dpdk.org; david.marchand@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>
>> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; stable@dpdk.org
>> Subject: [PATCH v4 4/7] vhost: fix NUMA reallocation with multiqueue
>>
>> Since the Vhost-user device initialization has been reworked,
>> enabling the application to start using the device as soon as
>> the first queue pair is ready, NUMA reallocation no more
>> happened on queue pairs other than the first one since
>> numa_realloc() was returning early if the device was running.
>>
>> This patch fixes this issue by only preventing the device
>> metadata to be allocated if the device is running. For the
>> virtqueues, a vring state change notification is sent to
>> notify the application of its disablement. Since the callback
>> is supposed to be blocking, it is safe to reallocate it
>> afterwards.
>
> Is there a corner case? Numa_realloc may happen during vhost-user msg
> set_vring_addr/kick, set_mem_table and iotlb msg. And iotlb msg will
> not take vq access lock. It could happen when numa_realloc happens on
> iotlb msg and app accesses vq in the meantime?
I think we are safe wrt to numa_realloc(), because the app's
.vring_state_changed() callback is only returning when it is no more
processing the rings.
> Thanks,
> Chenbo
>
>>
>> Fixes: d0fcc38f5fa4 ("vhost: improve device readiness notifications")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>> lib/vhost/vhost_user.c | 11 ++++++++---
>> 1 file changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
>> index 0e9e26ebe0..6e7b327ef8 100644
>> --- a/lib/vhost/vhost_user.c
>> +++ b/lib/vhost/vhost_user.c
>> @@ -488,9 +488,6 @@ numa_realloc(struct virtio_net *dev, int index)
>> struct batch_copy_elem *new_batch_copy_elems;
>> int ret;
>>
>> - if (dev->flags & VIRTIO_DEV_RUNNING)
>> - return dev;
>> -
>> old_dev = dev;
>> vq = old_vq = dev->virtqueue[index];
>>
>> @@ -506,6 +503,11 @@ numa_realloc(struct virtio_net *dev, int index)
>> return dev;
>> }
>> if (oldnode != newnode) {
>> + if (vq->ready) {
>> + vq->ready = false;
>> + vhost_user_notify_queue_state(dev, index, 0);
>> + }
>> +
>> VHOST_LOG_CONFIG(INFO,
>> "reallocate vq from %d to %d node\n", oldnode, newnode);
>> vq = rte_malloc_socket(NULL, sizeof(*vq), 0, newnode);
>> @@ -558,6 +560,9 @@ numa_realloc(struct virtio_net *dev, int index)
>> rte_free(old_vq);
>> }
>>
>> + if (dev->flags & VIRTIO_DEV_RUNNING)
>> + goto out;
>> +
>> /* check if we need to reallocate dev */
>> ret = get_mempolicy(&oldnode, NULL, 0, old_dev,
>> MPOL_F_NODE | MPOL_F_ADDR);
>> --
>> 2.31.1
>
next prev parent reply other threads:[~2021-06-18 8:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210617153739.178011-1-maxime.coquelin@redhat.com>
2021-06-17 15:37 ` [dpdk-stable] [PATCH v4 1/7] vhost: fix missing memory table NUMA realloc Maxime Coquelin
2021-06-18 4:34 ` Xia, Chenbo
2021-06-18 7:40 ` Maxime Coquelin
2021-06-17 15:37 ` [dpdk-stable] [PATCH v4 2/7] vhost: fix missing guest pages " Maxime Coquelin
2021-06-17 15:37 ` [dpdk-stable] [PATCH v4 4/7] vhost: fix NUMA reallocation with multiqueue Maxime Coquelin
2021-06-18 4:34 ` Xia, Chenbo
2021-06-18 8:01 ` Maxime Coquelin [this message]
2021-06-18 8:21 ` Xia, Chenbo
2021-06-18 8:48 ` Maxime Coquelin
2021-06-24 10:49 ` Xia, Chenbo
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