docs/about/deprecated.rst | 8 ++++++++ hw/i386/pc_piix.c | 1 + 2 files changed, 9 insertions(+)
The list of machine types grows larger and larger each release ... and
it is unlikely that many people still use the very old ones for live
migration. QEMU v1.7 has been released more than 8 years ago, so most
people should have updated their machines to a newer version in those
8 years at least once. Thus let's mark the very old 1.x machine types
as deprecated now.
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
docs/about/deprecated.rst | 8 ++++++++
hw/i386/pc_piix.c | 1 +
2 files changed, 9 insertions(+)
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index e21e07478f..652a4d43b6 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -318,6 +318,14 @@ machine is hardly emulated at all (e.g. neither the LCD nor the USB part had
been implemented), so there is not much value added by this board. Use the
``ref405ep`` machine instead.
+``pc-i440fx-1.4`` up to ``pc-i440fx-1.7`` (since 7.0)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+These old machine types are quite neglected nowadays and thus might have
+various pitfalls with regards to live migration. Use a newer machine type
+instead.
+
+
Backend options
---------------
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index d9b344248d..84f3633223 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -757,6 +757,7 @@ static void pc_i440fx_1_7_machine_options(MachineClass *m)
m->hw_version = "1.7.0";
m->default_machine_opts = NULL;
m->option_rom_has_mr = true;
+ m->deprecation_reason = "old and unattended - use a newer version instead";
compat_props_add(m->compat_props, pc_compat_1_7, pc_compat_1_7_len);
pcmc->smbios_defaults = false;
pcmc->gigabyte_align = false;
--
2.27.0
On Mon, Jan 17, 2022 at 08:16:39PM +0100, Thomas Huth wrote: > The list of machine types grows larger and larger each release ... and > it is unlikely that many people still use the very old ones for live > migration. QEMU v1.7 has been released more than 8 years ago, so most > people should have updated their machines to a newer version in those > 8 years at least once. Thus let's mark the very old 1.x machine types > as deprecated now. What criteria did you use for picking v1.7 as the end point ? I'm fine with the idea of aging out machine types, but I'd like us to explain the criteria we use for this, so that we can set clear expectations for users. I'm not a fan of adhoc decisions that have different impact every time we randomly decide to apply them. A simple rule could be time based - eg we could say "we'll keep machine type versions for 5 years or 15 releases." one factor is how long our downstream consumers have been keeping machines around for. In RHEL-9 for example, the oldest machine is "pc-i440fx-rhel7.6.0" which IIUC is derived from QEMU 2.12.0. RHEL-9 is likely to rebase QEMU quite a few times over the coming years, so that 2.12.0 version sets an example baseline for how long machines might need to live for. That's 4 years this April, and could potentially be 6-7 years by the time RHEL-9 stops rebasing QEMU. > > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > docs/about/deprecated.rst | 8 ++++++++ > hw/i386/pc_piix.c | 1 + > 2 files changed, 9 insertions(+) > > diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst > index e21e07478f..652a4d43b6 100644 > --- a/docs/about/deprecated.rst > +++ b/docs/about/deprecated.rst > @@ -318,6 +318,14 @@ machine is hardly emulated at all (e.g. neither the LCD nor the USB part had > been implemented), so there is not much value added by this board. Use the > ``ref405ep`` machine instead. > > +``pc-i440fx-1.4`` up to ``pc-i440fx-1.7`` (since 7.0) > +''''''''''''''''''''''''''''''''''''''''''''''''''''' > + > +These old machine types are quite neglected nowadays and thus might have > +various pitfalls with regards to live migration. Use a newer machine type > +instead. > + > + > Backend options > --------------- > > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c > index d9b344248d..84f3633223 100644 > --- a/hw/i386/pc_piix.c > +++ b/hw/i386/pc_piix.c > @@ -757,6 +757,7 @@ static void pc_i440fx_1_7_machine_options(MachineClass *m) > m->hw_version = "1.7.0"; > m->default_machine_opts = NULL; > m->option_rom_has_mr = true; > + m->deprecation_reason = "old and unattended - use a newer version instead"; > compat_props_add(m->compat_props, pc_compat_1_7, pc_compat_1_7_len); > pcmc->smbios_defaults = false; > pcmc->gigabyte_align = false; > -- > 2.27.0 > Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
On 17/01/2022 21.12, Daniel P. Berrangé wrote: > On Mon, Jan 17, 2022 at 08:16:39PM +0100, Thomas Huth wrote: >> The list of machine types grows larger and larger each release ... and >> it is unlikely that many people still use the very old ones for live >> migration. QEMU v1.7 has been released more than 8 years ago, so most >> people should have updated their machines to a newer version in those >> 8 years at least once. Thus let's mark the very old 1.x machine types >> as deprecated now. > > What criteria did you use for picking v1.7 as the end point ? I picked everything starting with a "1." this time ;-) No, honestly, since we don't have a deprecation policy in place yet, there was no real good criteria around this time. For the machine types < 1.3 there was a bug with migration, so these machine types could not be used for reliable migration anymore anyway. But for the newer machine types, we likely have to decide by other means indeed. > I'm fine with the idea of aging out machine types, but I'd like us > to explain the criteria we use for this, so that we can set clear > expectations for users. I'm not a fan of adhoc decisions that have > different impact every time we randomly decide to apply them. > > A simple rule could be time based - eg we could say > > "we'll keep machine type versions for 5 years or 15 releases." > > one factor is how long our downstream consumers have been keeping > machines around for. > > In RHEL-9 for example, the oldest machine is "pc-i440fx-rhel7.6.0" > which IIUC is derived from QEMU 2.12.0. RHEL-9 is likely to rebase > QEMU quite a few times over the coming years, so that 2.12.0 version > sets an example baseline for how long machines might need to live for. > That's 4 years this April, and could potentially be 6-7 years by the > time RHEL-9 stops rebasing QEMU. Yeah, 5 years still seemed a little bit short to me, that's one of the reasons why I did not add more machine types in my patch here. I think with 7 or 8 years, we should be on the safe side. Any other opinions? And if we agree on an amount of years, where should we document this? At the top of docs/about/deprecated.rst? Thomas
On 17/01/2022 20.16, Thomas Huth wrote: > The list of machine types grows larger and larger each release ... and > it is unlikely that many people still use the very old ones for live > migration. QEMU v1.7 has been released more than 8 years ago, so most > people should have updated their machines to a newer version in those > 8 years at least once. Thus let's mark the very old 1.x machine types > as deprecated now. > > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > docs/about/deprecated.rst | 8 ++++++++ > hw/i386/pc_piix.c | 1 + > 2 files changed, 9 insertions(+) > > diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst > index e21e07478f..652a4d43b6 100644 > --- a/docs/about/deprecated.rst > +++ b/docs/about/deprecated.rst > @@ -318,6 +318,14 @@ machine is hardly emulated at all (e.g. neither the LCD nor the USB part had > been implemented), so there is not much value added by this board. Use the > ``ref405ep`` machine instead. > > +``pc-i440fx-1.4`` up to ``pc-i440fx-1.7`` (since 7.0) > +''''''''''''''''''''''''''''''''''''''''''''''''''''' > + > +These old machine types are quite neglected nowadays and thus might have > +various pitfalls with regards to live migration. Use a newer machine type > +instead. > + > + > Backend options > --------------- > > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c > index d9b344248d..84f3633223 100644 > --- a/hw/i386/pc_piix.c > +++ b/hw/i386/pc_piix.c > @@ -757,6 +757,7 @@ static void pc_i440fx_1_7_machine_options(MachineClass *m) > m->hw_version = "1.7.0"; > m->default_machine_opts = NULL; > m->option_rom_has_mr = true; > + m->deprecation_reason = "old and unattended - use a newer version instead"; > compat_props_add(m->compat_props, pc_compat_1_7, pc_compat_1_7_len); > pcmc->smbios_defaults = false; > pcmc->gigabyte_align = false; *ping* Seems like the discussion about marking old machine types ceased very quickly ... but since nobody has written any concerns against this patch here, could we at least agree to apply this patch to get the deprecation timer started again for some machine types in 7.0 ? Thomas
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