Re: [PATCH v2 COLOPre 10/13] tools/libxl: Add back channel to allow migration target send data back

[Yang Hongyang <yanghy@cn.fujitsu.com>]

On 06/12/2015 08:54 PM, Wei Liu wrote:
> On Mon, Jun 08, 2015 at 11:43:14AM +0800, Yang Hongyang wrote:
>> From: Wen Congyang <wency@cn.fujitsu.com>
>>
>> In colo mode, slave needs to send data to master, but the io_fd
>> only can be written in master, and only can be read in slave.
>> Save recv_fd in domain_suspend_state, and send_fd in
>> domain_create_state.
>>
>
> You failed to mention in commit message new structures are introduced in
> IDL.
>
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
>> ---
>>   tools/libxl/libxl.c          |  2 +-
>>   tools/libxl/libxl_create.c   | 14 ++++++++++----
>>   tools/libxl/libxl_internal.h |  2 ++
>>   tools/libxl/libxl_types.idl  |  7 +++++++
>>   tools/libxl/xl_cmdimpl.c     |  7 +++++++
>
> You also need to add LIBXL_HAVE in libxl.h.
>
>>   5 files changed, 27 insertions(+), 5 deletions(-)
>>
>> diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
>> index 5c843c2..36b97fe 100644
>> --- a/tools/libxl/libxl.c
>> +++ b/tools/libxl/libxl.c
>> @@ -832,7 +832,7 @@ int libxl_domain_remus_start(libxl_ctx *ctx, libxl_domain_remus_info *info,
>>       dss->callback = remus_failover_cb;
>>       dss->domid = domid;
>>       dss->fd = send_fd;
>> -    /* TODO do something with recv_fd */
>> +    dss->recv_fd = recv_fd;
>>       dss->type = type;
>>       dss->live = 1;
>>       dss->debug = 0;
>> diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
>> index 86384d2..bd8149c 100644
>> --- a/tools/libxl/libxl_create.c
>> +++ b/tools/libxl/libxl_create.c
>> @@ -1577,8 +1577,8 @@ static void domain_create_cb(libxl__egc *egc,
>>                                int rc, uint32_t domid);
>>
>>   static int do_domain_create(libxl_ctx *ctx, libxl_domain_config *d_config,
>> -                            uint32_t *domid,
>> -                            int restore_fd, int checkpointed_stream,
>> +                            uint32_t *domid, int restore_fd,
>> +                            int send_fd, int checkpointed_stream,
>>                               const libxl_asyncop_how *ao_how,
>>                               const libxl_asyncprogress_how *aop_console_how)
>>   {
>> @@ -1591,6 +1591,7 @@ static int do_domain_create(libxl_ctx *ctx, libxl_domain_config *d_config,
>>       libxl_domain_config_init(&cdcs->dcs.guest_config_saved);
>>       libxl_domain_config_copy(ctx, &cdcs->dcs.guest_config_saved, d_config);
>>       cdcs->dcs.restore_fd = restore_fd;
>> +    cdcs->dcs.send_fd = send_fd;
>>       cdcs->dcs.callback = domain_create_cb;
>>       cdcs->dcs.checkpointed_stream = checkpointed_stream;
>>       libxl__ao_progress_gethow(&cdcs->dcs.aop_console_how, aop_console_how);
>> @@ -1619,7 +1620,7 @@ int libxl_domain_create_new(libxl_ctx *ctx, libxl_domain_config *d_config,
>>                               const libxl_asyncop_how *ao_how,
>>                               const libxl_asyncprogress_how *aop_console_how)
>>   {
>> -    return do_domain_create(ctx, d_config, domid, -1, 0,
>> +    return do_domain_create(ctx, d_config, domid, -1, -1, 0,
>>                               ao_how, aop_console_how);
>>   }
>>
>> @@ -1629,7 +1630,12 @@ int libxl_domain_create_restore(libxl_ctx *ctx, libxl_domain_config *d_config,
>>                                   const libxl_asyncop_how *ao_how,
>>                                   const libxl_asyncprogress_how *aop_console_how)
>>   {
>> -    return do_domain_create(ctx, d_config, domid, restore_fd,
>> +    int send_fd = -1;
>> +
>> +    if (params->checkpointed_stream == LIBXL_CHECKPOINTED_STREAM_COLO)
>> +        send_fd = params->send_fd;
>> +
>> +    return do_domain_create(ctx, d_config, domid, restore_fd, send_fd,
>>                               params->checkpointed_stream, ao_how, aop_console_how);
>>   }
>>
>> diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
>> index fbbae93..6d214b5 100644
>> --- a/tools/libxl/libxl_internal.h
>> +++ b/tools/libxl/libxl_internal.h
>> @@ -2874,6 +2874,7 @@ struct libxl__domain_save_state {
>>
>>       uint32_t domid;
>>       int fd;
>> +    int recv_fd;
>>       libxl_domain_type type;
>>       int live;
>>       int debug;
>> @@ -3143,6 +3144,7 @@ struct libxl__domain_create_state {
>>       libxl_domain_config *guest_config;
>>       libxl_domain_config guest_config_saved; /* vanilla config */
>>       int restore_fd;
>> +    int send_fd;
>>       libxl__domain_create_cb *callback;
>>       libxl_asyncprogress_how aop_console_how;
>>       /* private to domain_create */
>> diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
>> index 23f27d4..8a3d7ba 100644
>> --- a/tools/libxl/libxl_types.idl
>> +++ b/tools/libxl/libxl_types.idl
>> @@ -198,6 +198,12 @@ libxl_viridian_enlightenment = Enumeration("viridian_enlightenment", [
>>       (3, "reference_tsc"),
>>       ])
>>
>> +libxl_checkpointed_stream = Enumeration("checkpointed_stream", [
>> +    (0, "NONE"),
>> +    (1, "REMUS"),
>> +    (2, "COLO"),
>> +    ], init_val = 0)
>
> The default init_val is 0 so you don't need to write it down.

Okay.

>
>> +
>>   #
>>   # Complex libxl types
>>   #
>> @@ -346,6 +352,7 @@ libxl_domain_create_info = Struct("domain_create_info",[
>>
>>   libxl_domain_restore_params = Struct("domain_restore_params", [
>>       ("checkpointed_stream", integer),
>> +    ("send_fd", integer),
>
> I'm not entirely sure if we want to bury an extra argument here.
>
> After looking at code I think you're trying to work around API
> limitation. I think we are safe to extend the API -- we've already done
> that before. See libxl.h around line 990.
>
> Ian and Ian, what do you think?
>
>>       ])
>>
>>   libxl_domain_sched_params = Struct("domain_sched_params",[
>> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
>> index c858068..adfadd1 100644
>> --- a/tools/libxl/xl_cmdimpl.c
>> +++ b/tools/libxl/xl_cmdimpl.c
>
> I would also suggest you rename the last argument of migrate_receive in
> this file from "remus" to "checkpointed_stream_type" since the semantics
> of that parameter has changed.

I've renamed it to "checkpointed".

>
> Wei.
> .
>

-- 
Thanks,
Yang.