From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: "Liu, Changpeng" <changpeng.liu@intel.com>,
Stephen Hemminger <stephen@networkplumber.org>
Cc: "dev@dpdk.org" <dev@dpdk.org>, "Xia, Chenbo" <chenbo.xia@intel.com>
Subject: Re: [PATCH] vhost: use try_lock in rte_vhost_vring_call
Date: Tue, 20 Sep 2022 09:12:51 +0200 [thread overview]
Message-ID: <8be85d76-2671-57e1-58c2-30070428a66c@redhat.com> (raw)
In-Reply-To: <PH0PR11MB5093BD8DD6FEF5506F52B897EE419@PH0PR11MB5093.namprd11.prod.outlook.com>
On 9/7/22 02:40, Liu, Changpeng wrote:
>
>
>> -----Original Message-----
>> From: Stephen Hemminger <stephen@networkplumber.org>
>> Sent: Wednesday, September 7, 2022 5:16 AM
>> To: Liu, Changpeng <changpeng.liu@intel.com>
>> Cc: dev@dpdk.org; Maxime Coquelin <maxime.coquelin@redhat.com>; Xia,
>> Chenbo <chenbo.xia@intel.com>
>> Subject: Re: [PATCH] vhost: use try_lock in rte_vhost_vring_call
>>
>> On Tue, 6 Sep 2022 10:22:25 +0800
>> Changpeng Liu <changpeng.liu@intel.com> wrote:
>>
>>> Note that this function is in data path, so the thread context
>>> may not same as socket messages processing context, by using
>>> try_lock here, users can have another try in case of VQ's access
>>> lock is held by `vhost-events` thread.
>>>
>>> Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
>>> ---
>>> lib/vhost/vhost.c | 6 +++++-
>>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
>>> index 60cb05a0ff..072d2acb7b 100644
>>> --- a/lib/vhost/vhost.c
>>> +++ b/lib/vhost/vhost.c
>>> @@ -1329,7 +1329,11 @@ rte_vhost_vring_call(int vid, uint16_t vring_idx)
>>> if (!vq)
>>> return -1;
>>>
>>> - rte_spinlock_lock(&vq->access_lock);
>>> + if (!rte_spinlock_trylock(&vq->access_lock)) {
>>> + VHOST_LOG_CONFIG(dev->ifname, DEBUG,
>>> + "failed to kick guest, virtqueue busy.\n");
>>> + return -1;
>>> + }
>>>
>>
>> If it is a race, logging a message is not a good idea; the log will fill
>> with this noise.
>>
>> Instead make it statistic that can be seen by xstats.
> It's a DEBUG log, users can't see it in practice.
>
Having an xstat would enable live debugging & post-mortem analysis.
You can have both the stats and the debug log.
Regards,
Maxime
next prev parent reply other threads:[~2022-09-20 7:12 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-06 2:22 Changpeng Liu
2022-09-06 21:15 ` Stephen Hemminger
2022-09-07 0:40 ` Liu, Changpeng
2022-09-20 7:12 ` Maxime Coquelin [this message]
2022-09-20 2:24 ` Xia, Chenbo
2022-09-20 2:34 ` Liu, Changpeng
2022-09-20 2:53 ` Xia, Chenbo
2022-09-20 3:00 ` Liu, Changpeng
2022-09-20 7:23 ` Maxime Coquelin
2022-09-20 7:30 ` Maxime Coquelin
2022-09-20 7:19 ` Maxime Coquelin
2022-09-20 7:29 ` Liu, Changpeng
2022-09-20 7:34 ` Maxime Coquelin
2022-09-20 7:45 ` Liu, Changpeng
2022-09-20 8:12 ` Maxime Coquelin
2022-09-20 8:43 ` Liu, Changpeng
2022-09-21 9:41 ` Maxime Coquelin
2022-09-21 9:52 ` Liu, Changpeng
2022-10-11 11:56 ` Maxime Coquelin
2022-10-12 6:40 ` [PATCH v2] vhost: add new `rte_vhost_vring_call_nonblock` API Changpeng Liu
2022-10-13 7:56 ` Maxime Coquelin
2022-10-17 6:46 ` Xia, Chenbo
2022-10-17 7:17 ` Liu, Changpeng
2022-10-17 7:14 ` [PATCH v3] " Changpeng Liu
2022-10-17 7:39 ` Xia, Chenbo
2022-10-17 7:50 ` Liu, Changpeng
2022-10-17 7:48 ` [PATCH v4] " Changpeng Liu
2022-10-19 5:27 ` Xia, Chenbo
2022-10-26 9:24 ` Xia, Chenbo
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