Il 18/03/2013 21:33, Michael R. Hines ha scritto:
>>
>> +int qemu_drain(QEMUFile *f)
>> +{
>> + return f->ops->drain ? f->ops->drain(f->opaque) : 0;
>> +}
>> Hmm, this is very similar to qemu_fflush, but not quite. :/
>>
>> Why exactly is this needed?
>
> Good idea - I'll replace drain with flush once I added
> the "qemu_file_ops_are(const QEMUFile *, const QEMUFileOps *) "
> that you recommended......
If I understand correctly, the problem is that save_rdma_page is
asynchronous and you have to wait for pending operations to do the
put_buffer protocol correctly.
Would it work to just do the "drain" in the put_buffer operation, if and
only if it was preceded by a save_rdma_page operation?
>
>>> /** Flushes QEMUFile buffer
>>> *
>>> */
>>> @@ -723,6 +867,8 @@ int qemu_get_byte(QEMUFile *f)
>>> int64_t qemu_ftell(QEMUFile *f)
>>> {
>>> qemu_fflush(f);
>>> + if(migrate_use_rdma(f))
>>> + return delta_norm_mig_bytes_transferred();
>> Not needed, and another undesirable dependency (savevm.c ->
>> arch_init.c). Just update f->pos in save_rdma_page.
>
> f->pos isn't good enough because save_rdma_page does not
> go through QEMUFile directly - only non-live state goes
> through QEMUFile ....... pc.ram uses direct RDMA writes.
>
> As a result, the position pointer does not get updated
> and the accounting is missed........
Yes, I am suggesting to modify f->pos in save_rdma_page instead.
Paolo
