Re: [Qemu-devel] [RFC PATCH v4 03/28] COLO: migrate colo related info to slave

[zhanghailiang]

On 2015/5/15 19:38, 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 has been migrated from PVM.
> >
> > Signed-off-by: zhanghailiang <address@hidden>
> > Signed-off-by: Yang Hongyang <address@hidden>
> > Signed-off-by: Lai Jiangshan <address@hidden>
> > Signed-off-by: Gonglei <address@hidden>
> > ---
> >   include/migration/migration-colo.h |  2 ++
> >   migration/Makefile.objs            |  1 +
> >   migration/colo-comm.c              | 55 ++++++++++++++++++++++++++++++++++++++
> >   vl.c                               |  5 +++-
> >   4 files changed, 62 insertions(+), 1 deletion(-)
> >   create mode 100644 migration/colo-comm.c
> >
> > diff --git a/include/migration/migration-colo.h 
> > b/include/migration/migration-colo.h
> > index 6fdbb94..de68c72 100644
> > --- a/include/migration/migration-colo.h
> > +++ b/include/migration/migration-colo.h
> > @@ -14,7 +14,9 @@
> >   #define QEMU_MIGRATION_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..cab97e9
> > --- /dev/null
> > +++ b/migration/colo-comm.c
> > @@ -0,0 +1,55 @@
> > +/*
> > + * 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/migration-colo.h>
> > +
> > +#define DEBUG_COLO_COMMON 0
> > +
> > +#define DPRINTF(fmt, ...)                                  \
> > +    do {                                                   \
> > +        if (DEBUG_COLO_COMMON) {                           \
> > +            fprintf(stderr, "COLO: " fmt, ## __VA_ARGS__); \
> > +        }                                                  \
> > +    } while (0)
>
>
> I'm trying to get rid of all the DPRINTF's in migration - I've turned
> most of the existing DPRINTF into trace_ calls already;
> using the stderr trace backend it's very easy (--enable-trace-backends=stderr)
> and then you can switch them on individually, it also prints times with
> each message that's useful for performance tuning.

Yes, we should change all DPRINTF to trace_ calls. We will try to fix them in 
next version. ;)

Thanks,
zhanghailiang

> > +static bool colo_requested;
> > +
> > +/* save */
> > +static void colo_info_save(QEMUFile *f, void *opaque)
> > +{
> > +    qemu_put_byte(f, migrate_enable_colo());
> > +}
> > +
> > +/* restore */
> > +static int colo_info_load(QEMUFile *f, void *opaque, int version_id)
> > +{
> > +    int value = qemu_get_byte(f);
> > +
> > +    if (value && !colo_requested) {
> > +        DPRINTF("COLO requested!\n");
> > +    }
> > +    colo_requested = value;
> > +
> > +    return 0;
> > +}
> > +
> > +static SaveVMHandlers savevm_colo_info_handlers = {
> > +    .save_state = colo_info_save,
> > +    .load_state = colo_info_load,
> > +};
> > +
> > +void colo_info_mig_init(void)
> > +{
> > +    register_savevm_live(NULL, "colo", -1, 1,
> > +                         &savevm_colo_info_handlers, NULL);
> > +}
> > diff --git a/vl.c b/vl.c
> > index 75ec292..9724992 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -90,6 +90,7 @@ int main(int argc, char **argv)
> >   #include "sysemu/dma.h"
> >   #include "audio/audio.h"
> >   #include "migration/migration.h"
> > +#include "migration/migration-colo.h"
> >   #include "sysemu/kvm.h"
> >   #include "qapi/qmp/qjson.h"
> >   #include "qemu/option.h"
> > @@ -4149,7 +4150,9 @@ int main(int argc, char **argv, char **envp)
> >
> >       blk_mig_init();
> >       ram_mig_init();
> > -
> > +#ifdef CONFIG_COLO
> > +    colo_info_mig_init();
> > +#endif
> >       /* 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) {
> > --
> > 1.7.12.4
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK
>
> .