Re: [Qemu-devel] [PATCH 1/2] migration: implement io_set_aio_fd_handler function for RDMA QIOChannel

[858585 jemmy]

On Wed, May 9, 2018 at 1:10 AM, Dr. David Alan Gilbert
<address@hidden> wrote:
> * Juan Quintela (address@hidden) wrote:
>> Lidong Chen <address@hidden> wrote:
>> > if qio_channel_rdma_readv return QIO_CHANNEL_ERR_BLOCK, the destination 
>> > qemu
>> > crash.
>> >
>> > The backtrace is:
>> > (gdb) bt
>> >     #0  0x0000000000000000 in ?? ()
>> >     #1  0x00000000008db50e in qio_channel_set_aio_fd_handler 
>> > (ioc=0x38111e0, ctx=0x3726080,
>> >         io_read=0x8db841 <qio_channel_restart_read>, io_write=0x0, 
>> > opaque=0x38111e0) at io/channel.c:
>> >     #2  0x00000000008db952 in qio_channel_set_aio_fd_handlers 
>> > (ioc=0x38111e0) at io/channel.c:438
>> >     #3  0x00000000008dbab4 in qio_channel_yield (ioc=0x38111e0, 
>> > condition=G_IO_IN) at io/channel.c:47
>> >     #4  0x00000000007a870b in channel_get_buffer (opaque=0x38111e0, 
>> > buf=0x440c038 "", pos=0, size=327
>> >         at migration/qemu-file-channel.c:83
>> >     #5  0x00000000007a70f6 in qemu_fill_buffer (f=0x440c000) at 
>> > migration/qemu-file.c:299
>> >     #6  0x00000000007a79d0 in qemu_peek_byte (f=0x440c000, offset=0) at 
>> > migration/qemu-file.c:562
>> >     #7  0x00000000007a7a22 in qemu_get_byte (f=0x440c000) at 
>> > migration/qemu-file.c:575
>> >     #8  0x00000000007a7c78 in qemu_get_be32 (f=0x440c000) at 
>> > migration/qemu-file.c:655
>> >     #9  0x00000000007a0508 in qemu_loadvm_state (f=0x440c000) at 
>> > migration/savevm.c:2126
>> >     #10 0x0000000000794141 in process_incoming_migration_co (opaque=0x0) 
>> > at migration/migration.c:366
>> >     #11 0x000000000095c598 in coroutine_trampoline (i0=84033984, i1=0) at 
>> > util/coroutine-ucontext.c:1
>> >     #12 0x00007f9c0db56d40 in ?? () from /lib64/libc.so.6
>> >     #13 0x00007f96fe858760 in ?? ()
>> >     #14 0x0000000000000000 in ?? ()
>> >
>> > RDMA QIOChannel not implement io_set_aio_fd_handler. so
>> > qio_channel_set_aio_fd_handler will access NULL pointer.
>> >
>> > Signed-off-by: Lidong Chen <address@hidden>
>> > ---
>>
>>
>> Hi
>>
>> could you resend, it don't compile for me :-(
>
> This really sits after the other set of rdma changes.
> I doubt this path is reachable without the previous set.
>
> Dave

Hi Juan:
    I should not separate the patchset.  Sorry for this mistake. This
patch is base on another patch.
    http://patchwork.ozlabs.org/patch/909156/
    After Daniel have reviewed this patch, I will send the v4 version
which will include all patch for RDMA live migration.
    Thanks.

>>
>> /mnt/kvm/qemu/cleanup/migration/rdma.c: In function 
>> ‘qio_channel_rdma_set_aio_fd_handler’:
>> /mnt/kvm/qemu/cleanup/migration/rdma.c:2877:39: error: ‘QIOChannelRDMA’ {aka 
>> ‘struct QIOChannelRDMA’} has no member named ‘rdmain’; did you mean ‘rdma’?
>>          aio_set_fd_handler(ctx, rioc->rdmain->comp_channel->fd,
>>                                        ^~~~~~
>>                                        rdma
>> /mnt/kvm/qemu/cleanup/migration/rdma.c:2880:39: error: ‘QIOChannelRDMA’ {aka 
>> ‘struct QIOChannelRDMA’} has no member named ‘rdmaout’; did you mean ‘rdma’?
>>          aio_set_fd_handler(ctx, rioc->rdmaout->comp_channel->fd,
>>                                        ^~~~~~~
>>                                        rdma
>> make: *** [/mnt/kvm/qemu/cleanup/rules.mak:66: migration/rdma.o] Error 1
>>   CC      migration/block.o
>>   CC      ui/vnc.o
>>
>> It seems like
>>
>> > diff --git a/migration/rdma.c b/migration/rdma.c
>> > index 92e4d30..dfa4f77 100644
>> > --- a/migration/rdma.c
>> > +++ b/migration/rdma.c
>> > @@ -2963,6 +2963,21 @@ static GSource 
>> > *qio_channel_rdma_create_watch(QIOChannel *ioc,
>> >      return source;
>> >  }
>> >
>> > +static void qio_channel_rdma_set_aio_fd_handler(QIOChannel *ioc,
>> > +                                                  AioContext *ctx,
>> > +                                                  IOHandler *io_read,
>> > +                                                  IOHandler *io_write,
>> > +                                                  void *opaque)
>> > +{
>> > +    QIOChannelRDMA *rioc = QIO_CHANNEL_RDMA(ioc);
>> > +    if (io_read) {
>> > +        aio_set_fd_handler(ctx, rioc->rdmain->comp_channel->fd,
>>
>>         this should be rioc->rdam->comp_channel
>>
>> > +                           false, io_read, io_write, NULL, opaque);
>> > +    } else {
>> > +        aio_set_fd_handler(ctx, rioc->rdmaout->comp_channel->fd,
>>
>> and this rioc-rdma->comp_channel
>>
>> But will preffer if you confirm.
>>
>> Thanks.
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK