On Wed, 14 Jan 2026 15:11:55 -0500 Peter Xu <[email protected]> wrote:
> On Wed, Jan 14, 2026 at 02:56:57PM -0500, Peter Xu wrote: > > COLO was broken for QEMU release 10.0/10.1 without anyone noticed. One > > reason might be that we don't have an unit test for COLO (which we > > explicitly require now for any new migration feature). The other reason > > should be that there are just no more active COLO users, at least based on > > the latest development of QEMU. > > > > I don't remember seeing anything really active in the past few years in > > COLO development. > > > > Meanwhile, COLO migration framework maintainer (Hailiang Zhang)'s last > > email to qemu-devel is in Dec 2021 where the patch proposed an email > > change (<[email protected]>). > > > > We've discussed this for a while, see latest discussions here (our thoughts > > of deprecating COLO framework might be earlier than that, but still): > > > > https://lore.kernel.org/r/[email protected]/ > > https://lore.kernel.org/r/[email protected] > > > > Let's make it partly official and put COLO into deprecation list. If > > anyone cares about COLO and is deploying it, please send an email to > > qemu-devel to discuss. > > > > Otherwise, let's try to save some energy for either maintainers or > > developers who is looking after QEMU. Let's save the work if we don't even > > know what the work is for. > > > > Cc: Lukáš Doktor <[email protected]> > > My apologize, I copied the wrong email. > > Cc: Lukas Straub <[email protected]> Nack. This code has users, as explained in my other email: https://lore.kernel.org/qemu-devel/20260115224516.7f0309ba@penguin/T/#mc99839451d6841366619c4ec0d5af5264e2f6464 Regards, Lukas Straub > > > Cc: Juan Quintela <[email protected]> > > Cc: Dr. David Alan Gilbert <[email protected]> > > Cc: Zhang Chen <[email protected]> > > Cc: [email protected] > > Cc: Li Zhijian <[email protected]> > > Cc: Jason Wang <[email protected]> > > Signed-off-by: Peter Xu <[email protected]> > > --- > > docs/about/deprecated.rst | 6 ++++++ > > qapi/migration.json | 5 ++--- > > migration/options.c | 4 ++++ > > 3 files changed, 12 insertions(+), 3 deletions(-) > > > > diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst > > index 7abb3dab59..b499b2acb0 100644 > > --- a/docs/about/deprecated.rst > > +++ b/docs/about/deprecated.rst > > @@ -580,3 +580,9 @@ command documentation for details on the ``fdset`` > > usage. > > > > The ``zero-blocks`` capability was part of the block migration which > > doesn't exist anymore since it was removed in QEMU v9.1. > > + > > +COLO migration framework (since 11.0) > > +''''''''''''''''''''''''''''''''''''' > > + > > +To be removed with no replacement, as the COLO migration framework doesn't > > +seem to have any active user for a while. > > diff --git a/qapi/migration.json b/qapi/migration.json > > index 201dedd982..3c868efe38 100644 > > --- a/qapi/migration.json > > +++ b/qapi/migration.json > > @@ -531,8 +531,7 @@ > > # > > # @unstable: Members @x-colo and @x-ignore-shared are experimental. > > # > > -# @deprecated: Member @zero-blocks is deprecated as being part of > > -# block migration which was already removed. > > +# @deprecated: Member @zero-blocks and @x-colo are deprecated. > > # > > # Since: 1.2 > > ## > > @@ -540,7 +539,7 @@ > > 'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', > > { 'name': 'zero-blocks', 'features': [ 'deprecated' ] }, > > 'events', 'postcopy-ram', > > - { 'name': 'x-colo', 'features': [ 'unstable' ] }, > > + { 'name': 'x-colo', 'features': [ 'unstable', 'deprecated' ] }, > > 'release-ram', > > 'return-path', 'pause-before-switchover', 'multifd', > > 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate', > > diff --git a/migration/options.c b/migration/options.c > > index 9a5a39c886..318850ba94 100644 > > --- a/migration/options.c > > +++ b/migration/options.c > > @@ -580,6 +580,10 @@ bool migrate_caps_check(bool *old_caps, bool > > *new_caps, Error **errp) > > warn_report("zero-blocks capability is deprecated"); > > } > > > > + if (new_caps[MIGRATION_CAPABILITY_X_COLO]) { > > + warn_report("COLO migration framework is deprecated"); > > + } > > + > > #ifndef CONFIG_REPLICATION > > if (new_caps[MIGRATION_CAPABILITY_X_COLO]) { > > error_setg(errp, "QEMU compiled without replication module" > > -- > > 2.50.1 > > >
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