Re: [Xen-devel] [PATCH v5 04/14] libxc/migration: Pass checkpoint information into the save algorithm.

[Yang Hongyang <yanghy@xxxxxxxxxxxxxx>]

On 05/13/2015 11:49 PM, Ian Campbell wrote:
> On Wed, 2015-05-13 at 09:53 +0800, Yang Hongyang wrote:
> > From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> OOI how was this signalled to the old code?
The old code check the callbacks "postcopy & checkpoint",
if the callbacks exists, it will call them which I think is
unreliable, so I add this flag to explicitly indicate a
checkpointed stream in the new code. However, it is backward
compatible, the legacy migration just don't know this flag
and will ignore it.

> > Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> > CC: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
> > CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
> > CC: Wei Liu <wei.liu2@xxxxxxxxxx>
> > CC: Yang Hongyang <yanghy@xxxxxxxxxxxxxx>
> > ---
> >   tools/libxc/include/xenguest.h | 1 +
> >   tools/libxc/xc_sr_common.h     | 3 +++
> >   tools/libxc/xc_sr_save.c       | 3 +++
> >   tools/libxl/libxl_dom.c        | 1 +
> >   4 files changed, 8 insertions(+)
> >
> > diff --git a/tools/libxc/include/xenguest.h b/tools/libxc/include/xenguest.h
> > index 8e39075..7581263 100644
> > --- a/tools/libxc/include/xenguest.h
> > +++ b/tools/libxc/include/xenguest.h
> > @@ -30,6 +30,7 @@
> >   #define XCFLAGS_HVM       (1 << 2)
> >   #define XCFLAGS_STDVGA    (1 << 3)
> >   #define XCFLAGS_CHECKPOINT_COMPRESS    (1 << 4)
> > +#define XCFLAGS_CHECKPOINTED    (1 << 5)
> >
> >   #define X86_64_B_SIZE   64
> >   #define X86_32_B_SIZE   32
> > diff --git a/tools/libxc/xc_sr_common.h b/tools/libxc/xc_sr_common.h
> > index c4fe92c..c0f90d4 100644
> > --- a/tools/libxc/xc_sr_common.h
> > +++ b/tools/libxc/xc_sr_common.h
> > @@ -174,6 +174,9 @@ struct xc_sr_context
> >               /* Live migrate vs non live suspend. */
> >               bool live;
> >
> > +            /* Plain VM, or checkpoints over time. */
> > +            bool checkpointed;
> > +
> >               /* Further debugging information in the stream. */
> >               bool debug;
> >
> > diff --git a/tools/libxc/xc_sr_save.c b/tools/libxc/xc_sr_save.c
> > index 66fcd3e..caa727d 100644
> > --- a/tools/libxc/xc_sr_save.c
> > +++ b/tools/libxc/xc_sr_save.c
> > @@ -732,6 +732,7 @@ int xc_domain_save2(xc_interface *xch, int io_fd, uint32_t 
> > dom,
> >       ctx.save.callbacks = callbacks;
> >       ctx.save.live  = !!(flags & XCFLAGS_LIVE);
> >       ctx.save.debug = !!(flags & XCFLAGS_DEBUG);
> > +    ctx.save.checkpointed = !!(flags & XCFLAGS_CHECKPOINTED);
> >
> >       /*
> >        * TODO: Find some time to better tweak the live migration algorithm.
> > @@ -745,6 +746,8 @@ int xc_domain_save2(xc_interface *xch, int io_fd, uint32_t 
> > dom,
> >       /* Sanity checks for callbacks. */
> >       if ( hvm )
> >           assert(callbacks->switch_qemu_logdirty);
> > +    if ( ctx.save.checkpointed )
> > +        assert(callbacks->checkpoint && callbacks->postcopy);
> >
> >       IPRINTF("In experimental %s", __func__);
> >       DPRINTF("fd %d, dom %u, max_iters %u, max_factor %u, flags %u, hvm %d",
> > diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
> > index f408646..a0c9850 100644
> > --- a/tools/libxl/libxl_dom.c
> > +++ b/tools/libxl/libxl_dom.c
> > @@ -2003,6 +2003,7 @@ void libxl__domain_suspend(libxl__egc *egc, 
> > libxl__domain_suspend_state *dss)
> >
> >       if (r_info != NULL) {
> >           dss->interval = r_info->interval;
> > +        dss->xcflags |= XCFLAGS_CHECKPOINTED;
> >           if (libxl_defbool_val(r_info->compression))
> >               dss->xcflags |= XCFLAGS_CHECKPOINT_COMPRESS;
> >       }
>
> .
--
Thanks,
Yang.

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