Re: [PATCH v4 05/18] migration/rdma: do not need sync main for rdma

[Zheng Chuan]

On 2021/2/4 2:10, Dr. David Alan Gilbert wrote:
> This patch needs to explain why the sync isn't needed for RDMA.
> 
> Dave
> 
OK. the multifd with tcp will send pages if it has pages to send by the record 
of multifd_send_state->pages->used while
RDMA is using rdma_write_hooks.

> * Chuan Zheng (zhengchuan@huawei.com) wrote:
>> Signed-off-by: Zhimin Feng <fengzhimin1@huawei.com>
>> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
>> ---
>>  migration/multifd.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
>> diff --git a/migration/multifd.c b/migration/multifd.c
>> index 4820702..5d34950 100644
>> --- a/migration/multifd.c
>> +++ b/migration/multifd.c
>> @@ -583,6 +583,10 @@ void multifd_send_sync_main(QEMUFile *f)
>>      if (!migrate_use_multifd()) {
>>          return;
>>      }
>> +     /* Do not need sync for rdma */
>> +    if (migrate_use_rdma()) {
>> +        return;
>> +    }
>>      if (multifd_send_state->pages->used) {
>>          if (multifd_send_pages(f) < 0) {
>>              error_report("%s: multifd_send_pages fail", __func__);
>> @@ -1024,6 +1028,10 @@ void multifd_recv_sync_main(void)
>>      if (!migrate_use_multifd()) {
>>          return;
>>      }
>> +    /* Do not need sync for rdma */
>> +    if (migrate_use_rdma()) {
>> +        return;
>> +    }
>>      for (i = 0; i < migrate_multifd_channels(); i++) {
>>          MultiFDRecvParams *p = &multifd_recv_state->params[i];
>>  
>> -- 
>> 1.8.3.1
>>

-- 
Regards.
Chuan