Re: [Qemu-devel] [PATCH COLO-Frame v9 03/32] COLO: migrate colo related info to slave

[zhanghailiang]

On 2015/10/3 2:45, Dr. David Alan Gilbert wrote:
> * zhanghailiang (address@hidden) wrote:
> > We can know if VM in destination should go into COLO mode by refer to
> > the info that been migrated from PVM.
> >
> > We skip this section if colo is not enabled (i.e.
> > migrate_set_capability colo off), so that, It not break compatibility with 
> > migration
> > however the --enable-colo/disable-colo on the source/destination;
> >
> > Signed-off-by: zhanghailiang <address@hidden>
> > Signed-off-by: Yang Hongyang <address@hidden>
> > Signed-off-by: Gonglei <address@hidden>
> > ---
> >   include/migration/colo.h |  2 ++
> >   migration/Makefile.objs  |  1 +
> >   migration/colo-comm.c    | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
> >   vl.c                     |  3 ++-
> >   4 files changed, 59 insertions(+), 1 deletion(-)
> >   create mode 100644 migration/colo-comm.c
> >
> > diff --git a/include/migration/colo.h b/include/migration/colo.h
> > index c60a590..9b6662d 100644
> > --- a/include/migration/colo.h
> > +++ b/include/migration/colo.h
> > @@ -14,7 +14,9 @@
> >   #define QEMU_COLO_H
> >
> >   #include "qemu-common.h"
> > +#include "migration/migration.h"
> >
> >   bool colo_supported(void);
> > +void colo_info_mig_init(void);
> >
> >   #endif
> > diff --git a/migration/Makefile.objs b/migration/Makefile.objs
> > index 5a25d39..cb7bd30 100644
> > --- a/migration/Makefile.objs
> > +++ b/migration/Makefile.objs
> > @@ -1,5 +1,6 @@
> >   common-obj-y += migration.o tcp.o
> >   common-obj-$(CONFIG_COLO) += colo.o
> > +common-obj-y += colo-comm.o
> >   common-obj-y += vmstate.o
> >   common-obj-y += qemu-file.o qemu-file-buf.o qemu-file-unix.o qemu-file-stdio.o
> >   common-obj-y += xbzrle.o
> > diff --git a/migration/colo-comm.c b/migration/colo-comm.c
> > new file mode 100644
> > index 0000000..4330bd8
> > --- /dev/null
> > +++ b/migration/colo-comm.c
> > @@ -0,0 +1,54 @@
> > +/*
> > + * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
> > + * (a.k.a. Fault Tolerance or Continuous Replication)
> > + *
> > + * Copyright (c) 2015 HUAWEI TECHNOLOGIES CO., LTD.
> > + * Copyright (c) 2015 FUJITSU LIMITED
> > + * Copyright (c) 2015 Intel Corporation
> > + *
> > + * This work is licensed under the terms of the GNU GPL, version 2 or
> > + * later. See the COPYING file in the top-level directory.
> > + *
> > + */
> > +
> > +#include <migration/colo.h>
> > +#include "trace.h"
> > +
> > +typedef struct {
> > +     uint32_t colo_requested;
> > +} COLOInfo;
> > +
> > +static COLOInfo colo_info;
> > +
> > +static void colo_info_pre_save(void *opaque)
> > +{
> > +    COLOInfo *s = opaque;
> > +
> > +    if (migrate_enable_colo()) {
> > +        s->colo_requested = 1;
> > +    } else {
> > +        s->colo_requested = 0;
> > +    }
> > +}
> > +
> > +static bool colo_info_need(void *opaque)
> > +{
> > +   return migrate_enable_colo();
> > +}
> > +
> > +static const VMStateDescription colo_state = {
> > +     .name = "COLOState",
> > +     .version_id = 1,
> > +     .minimum_version_id = 1,
> > +     .pre_save = colo_info_pre_save,
> > +     .needed = colo_info_need,
> > +     .fields = (VMStateField[]) {
> > +         VMSTATE_UINT32(colo_requested, COLOInfo),
>
> Any reason not to do it as a bool, and use VMSTATE_BOOL?
> (That would also simplify the pre_save).

No special reason, use VMSTATE_BOOL is a good idea, will fix
in next version, thanks.

zhanghailiang
> (Oddly you don't actually need the state at all - just
> the presence of the section is enough, but I don't worry
> about that).
>
> Dave
>
> > +         VMSTATE_END_OF_LIST()
> > +        },
> > +};
> > +
> > +void colo_info_mig_init(void)
> > +{
> > +    vmstate_register(NULL, 0, &colo_state, &colo_info);
> > +}
> > diff --git a/vl.c b/vl.c
> > index aee931a..571347a 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -92,6 +92,7 @@ int main(int argc, char **argv)
> >   #include "sysemu/dma.h"
> >   #include "audio/audio.h"
> >   #include "migration/migration.h"
> > +#include "migration/colo.h"
> >   #include "sysemu/kvm.h"
> >   #include "qapi/qmp/qjson.h"
> >   #include "qemu/option.h"
> > @@ -4446,7 +4447,7 @@ int main(int argc, char **argv, char **envp)
> >
> >       blk_mig_init();
> >       ram_mig_init();
> > -
> > +    colo_info_mig_init();
> >       /* If the currently selected machine wishes to override the units-per-bus
> >        * property of its default HBA interface type, do so now. */
> >       if (machine_class->units_per_default_bus) {
> > --
> > 1.8.3.1
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK
>
> .