From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
To: "Tan, Jianfeng" <jianfeng.tan@intel.com>, dev@dpdk.org
Cc: thomas@monjalon.net
Subject: Re: [dpdk-dev] [PATCH v3 2/5] bus/vdev: add lock on vdev device list
Date: Fri, 20 Apr 2018 16:16:38 +0100 [thread overview]
Message-ID: <b97ab0a2-b9c6-0509-7d88-28e384feacc6@intel.com> (raw)
In-Reply-To: <0025fac5-c007-c793-c3f7-2168343a1026@intel.com>
On 20-Apr-18 3:19 PM, Tan, Jianfeng wrote:
>
>
> On 4/20/2018 4:26 PM, Burakov, Anatoly wrote:
>> On 19-Apr-18 5:50 PM, Jianfeng Tan wrote:
>>> As we could add virtual devices from different threads now, we
>>> add a spin lock to protect the vdev device list.
>>>
>>> Suggested-by: Anatoly Burakov <anatoly.burakov@intel.com>
>>> Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
>>> Reviewed-by: Qi Zhang <qi.z.zhang@intel.com>
>>> ---
>>
>> <...>
>>
>>> +/* The caller shall be responsible for thread-safe */
>>> static struct rte_vdev_device *
>>> find_vdev(const char *name)
>>> {
>>> @@ -203,10 +206,6 @@ rte_vdev_init(const char *name, const char *args)
>>> if (name == NULL)
>>> return -EINVAL;
>>> - dev = find_vdev(name);
>>> - if (dev)
>>> - return -EEXIST;
>>> -
>>> devargs = alloc_devargs(name, args);
>>> if (!devargs)
>>> return -ENOMEM;
>>> @@ -221,16 +220,28 @@ rte_vdev_init(const char *name, const char *args)
>>> dev->device.numa_node = SOCKET_ID_ANY;
>>> dev->device.name = devargs->name;
>>> + rte_spinlock_lock(&vdev_device_list_lock);
>>> + if (find_vdev(name)) {
>>> + rte_spinlock_unlock(&vdev_device_list_lock);
>>> + ret = -EEXIST;
>>> + goto fail;
>>> + }
>>> + TAILQ_INSERT_TAIL(&vdev_device_list, dev, next);
>>> + rte_spinlock_unlock(&vdev_device_list_lock);
>>> +
>>
>> I wonder if is possible to just leave the tailq locked until you
>> either insert the device into tailq, or figure out that it's not
>> possible? Seems like doing two locks here is unnecessary, unless
>> vdev_probe_all_drivers needs this tailq unlocked...
>
> My opinion is that we don't know what could be done in driver probe().
> It could possibly insert a new vdev (it does not happen now, but could
> happen in future?). So here, we call this with tailq unlocked. Or we
> keep it as simple as possible as you say?
I thought this code was responsible for inserting vdevs? I think it
would be generally bad design to insert vdev while inserting vdev :)
That said, it's a fair point, and i don't have a strong opinion on this,
so you can leave it as is if you want.
--
Thanks,
Anatoly
next prev parent reply other threads:[~2018-04-20 15:16 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-04 15:30 [dpdk-dev] [PATCH 0/4] allow procinfo and pdump on eth vdev Jianfeng Tan
2018-03-04 15:30 ` [dpdk-dev] [PATCH 1/4] eal: bring forward multi-process channel init Jianfeng Tan
2018-03-04 15:30 ` [dpdk-dev] [PATCH 2/4] bus/vdev: bus scan by multi-process channel Jianfeng Tan
2018-03-05 9:36 ` Burakov, Anatoly
2018-03-06 0:50 ` Tan, Jianfeng
2018-03-07 14:00 ` Burakov, Anatoly
2018-03-12 3:22 ` Tan, Jianfeng
2018-03-04 15:30 ` [dpdk-dev] [PATCH 3/4] drivers/net: do not allocate rte_eth_dev_data privately Jianfeng Tan
2018-03-06 6:07 ` Matan Azrad
2018-03-06 8:55 ` Tan, Jianfeng
2018-03-07 6:00 ` Matan Azrad
2018-03-07 6:10 ` Matan Azrad
2018-03-12 3:40 ` Tan, Jianfeng
2018-03-04 15:30 ` [dpdk-dev] [PATCH 4/4] drivers/net: share vdev data to secondary process Jianfeng Tan
2018-04-19 16:50 ` [dpdk-dev] [PATCH v3 0/5] allow procinfo and pdump on eth vdev Jianfeng Tan
2018-04-19 16:50 ` [dpdk-dev] [PATCH v3 1/5] eal: bring forward multi-process channel init Jianfeng Tan
2018-04-20 8:16 ` Burakov, Anatoly
2018-04-20 14:08 ` Tan, Jianfeng
2018-04-19 16:50 ` [dpdk-dev] [PATCH v3 2/5] bus/vdev: add lock on vdev device list Jianfeng Tan
2018-04-20 8:26 ` Burakov, Anatoly
2018-04-20 14:19 ` Tan, Jianfeng
2018-04-20 15:16 ` Burakov, Anatoly [this message]
2018-04-20 15:23 ` Tan, Jianfeng
2018-04-19 16:50 ` [dpdk-dev] [PATCH v3 3/5] bus/vdev: bus scan by multi-process channel Jianfeng Tan
2018-04-20 8:41 ` Burakov, Anatoly
2018-04-20 14:28 ` Tan, Jianfeng
2018-04-20 15:19 ` Burakov, Anatoly
2018-04-20 15:32 ` Tan, Jianfeng
2018-04-20 15:39 ` Burakov, Anatoly
2018-04-19 16:50 ` [dpdk-dev] [PATCH v3 4/5] drivers/net: not use private eth dev data Jianfeng Tan
2018-04-19 16:50 ` [dpdk-dev] [PATCH v3 5/5] drivers/net: share vdev data to secondary process Jianfeng Tan
2018-04-20 16:57 ` [dpdk-dev] [PATCH v4 0/5] allow procinfo and pdump on eth vdev Jianfeng Tan
2018-04-20 16:57 ` [dpdk-dev] [PATCH v4 1/5] eal: bring forward multi-process channel init Jianfeng Tan
2018-04-20 16:57 ` [dpdk-dev] [PATCH v4 2/5] bus/vdev: add lock on vdev device list Jianfeng Tan
2018-04-23 9:47 ` Burakov, Anatoly
2018-04-20 16:57 ` [dpdk-dev] [PATCH v4 3/5] bus/vdev: bus scan by multi-process channel Jianfeng Tan
2018-04-23 9:54 ` Burakov, Anatoly
2018-04-24 5:22 ` Tan, Jianfeng
2018-04-20 16:57 ` [dpdk-dev] [PATCH v4 4/5] drivers/net: not use private eth dev data Jianfeng Tan
2018-04-20 16:57 ` [dpdk-dev] [PATCH v4 5/5] drivers/net: share vdev data to secondary process Jianfeng Tan
2018-04-24 5:51 ` [dpdk-dev] [PATCH v5 0/5] allow procinfo and pdump on eth vdev Jianfeng Tan
2018-04-24 5:51 ` [dpdk-dev] [PATCH v5 1/5] eal: bring forward multi-process channel init Jianfeng Tan
2018-04-24 5:51 ` [dpdk-dev] [PATCH v5 2/5] bus/vdev: add lock on vdev device list Jianfeng Tan
2018-04-24 5:51 ` [dpdk-dev] [PATCH v5 3/5] bus/vdev: bus scan by multi-process channel Jianfeng Tan
2018-04-24 10:09 ` Thomas Monjalon
2018-04-24 5:51 ` [dpdk-dev] [PATCH v5 4/5] drivers/net: not use private eth dev data Jianfeng Tan
2018-04-24 5:51 ` [dpdk-dev] [PATCH v5 5/5] drivers/net: share vdev data to secondary process Jianfeng Tan
2018-04-24 10:32 ` [dpdk-dev] [PATCH v5 0/5] allow procinfo and pdump on eth vdev Thomas Monjalon
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