[ovs-dev] [PATCH V3 08/19] netdev-offload-dpdk: Protect UFID map by mutex

[Eli Britstein]

On 12/9/2019 9:15 AM, 贺鹏 wrote:
> Hi,
>
>
> cmap support multiple readers and one writer.
> since all write operations are performed in the offload thread,
> why need a mutex here? Maybe I miss some patches.
Collecting statistics using netdev_flow_get in patch 10/20 is another 
thread. There, it gets the rte_flow, but if not protected it might get 
destroyed by the offload thread before it uses it.
>
>
>
> Eli Britstein <elibr at mellanox.com> 于2019年12月8日周日 下午9:23写道：
>
>> Flow deletion and dumping for statistics collection are called from
>> different threads. As a pre-step towards collecting HW statistics,
>> protect the UFID map by mutex to make it thread safe.
>>
>> Signed-off-by: Eli Britstein <elibr at mellanox.com>
>> ---
>>   lib/netdev-offload-dpdk.c | 7 ++++++-
>>   1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/netdev-offload-dpdk.c b/lib/netdev-offload-dpdk.c
>> index b2ec05cec..5568400b6 100644
>> --- a/lib/netdev-offload-dpdk.c
>> +++ b/lib/netdev-offload-dpdk.c
>> @@ -51,6 +51,7 @@ static struct vlog_rate_limit error_rl = VLOG_RATE_LIMIT_INIT(100, 5);
>>    * A mapping from ufid to dpdk rte_flow.
>>    */
>>   static struct cmap ufid_to_rte_flow = CMAP_INITIALIZER;
>> +static struct ovs_mutex ufid_map_mutex = OVS_MUTEX_INITIALIZER;
>>
>>   struct ufid_to_rte_flow_data {
>>       struct cmap_node node;
>> @@ -630,8 +631,11 @@ netdev_offload_dpdk_destroy_flow(struct netdev *netdev,
>>                                    struct rte_flow *rte_flow)
>>   {
>>       struct rte_flow_error error;
>> -    int ret = netdev_dpdk_rte_flow_destroy(netdev, rte_flow, &error);
>> +    int ret;
>> +
>> +    ovs_mutex_lock(&ufid_map_mutex);
>>
>> +    ret = netdev_dpdk_rte_flow_destroy(netdev, rte_flow, &error);
>>       if (ret == 0) {
>>           ufid_to_rte_flow_disassociate(ufid);
>>           VLOG_DBG("%s: removed rte flow %p associated with ufid " UUID_FMT "\n",
>> @@ -642,6 +646,7 @@ netdev_offload_dpdk_destroy_flow(struct netdev *netdev,
>>                    netdev_get_name(netdev), error.message, error.type);
>>       }
>>
>> +    ovs_mutex_unlock(&ufid_map_mutex);
>>       return ret;
>>   }
>>
>> --
>> 2.14.5
>>
>> _______________________________________________
>> dev mailing list
>> dev at openvswitch.org
>> https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.openvswitch.org%2Fmailman%2Flistinfo%2Fovs-dev&data=02%7C01%7Celibr%40mellanox.com%7C9af2f119de544768711408d77c779a66%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0%7C0%7C637114725449215533&sdata=VyrLUh6%2BP0ne9dXUSDjME31NBj0tHTV%2FEciNZY%2Baugo%3D&reserved=0
>
>
> --
> hepeng
> ICT