| Message ID | 1412358473-31398-29-git-send-email-dgilbert@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Fri, Oct 03, 2014 at 06:47:34PM +0100, Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > When postcopy calls qemu_savevm_state_complete it's not really > the end of migration, so skip: > a) Finishing postcopiable iterative devices - they'll carry on > b) The termination byte on the end of the stream. > > We then also add: > qemu_savevm_state_postcopy_complete > which is called at the end of a postcopy migration to call the > complete methods on devices skipped in the _complete call. So, we should probably rename qemu_savevm_state_complete() to reflect the fact that it's no longer actually a completion, but just the transition from pre-copy to post-copy phases. A good, brief name doesn't immediately occur to me, unfortunately. > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > --- > include/sysemu/sysemu.h | 1 + > savevm.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 52 insertions(+), 1 deletion(-) > > diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h > index e7ff3d0..46665ce 100644 > --- a/include/sysemu/sysemu.h > +++ b/include/sysemu/sysemu.h > @@ -113,6 +113,7 @@ void qemu_savevm_state_cancel(void); > void qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size, > uint64_t *res_non_postcopiable, > uint64_t *res_postcopiable); > +void qemu_savevm_state_postcopy_complete(QEMUFile *f); > void qemu_savevm_command_send(QEMUFile *f, enum qemu_vm_cmd command, > uint16_t len, uint8_t *data); > void qemu_savevm_send_reqack(QEMUFile *f, uint32_t value); > diff --git a/savevm.c b/savevm.c > index a0cb88b..7c4541d 100644 > --- a/savevm.c > +++ b/savevm.c > @@ -854,10 +854,51 @@ int qemu_savevm_state_iterate(QEMUFile *f) > return ret; > } > > +/* > + * Calls the complete routines just for those devices that are postcopiable; > + * causing the last few pages to be sent immediately and doing any associated > + * cleanup. > + * Note postcopy also calls the plain qemu_savevm_state_complete to complete > + * all the other devices, but that happens at the point we switch to postcopy. > + */ > +void qemu_savevm_state_postcopy_complete(QEMUFile *f) > +{ > + SaveStateEntry *se; > + int ret; > + > + QTAILQ_FOREACH(se, &savevm_handlers, entry) { > + if (!se->ops || !se->ops->save_live_complete || > + !se->ops->can_postcopy) { So, you check for the presence of a can_postcopy callback, but you don't ever actually invoke it. > + continue; > + } > + if (se->ops && se->ops->is_active) { > + if (!se->ops->is_active(se->opaque)) { > + continue; > + } > + } > + trace_savevm_section_start(se->idstr, se->section_id); > + /* Section type */ > + qemu_put_byte(f, QEMU_VM_SECTION_END); > + qemu_put_be32(f, se->section_id); > + > + ret = se->ops->save_live_complete(f, se->opaque); I'm wondering if it might be clearer not to overload the save_live_complete hook, but instead allow both "execution transition" (old complete) and "final complete" (postcopy complete) hooks (expecting only one to be non-NULL in most cases).
* David Gibson (david@gibson.dropbear.id.au) wrote: > On Fri, Oct 03, 2014 at 06:47:34PM +0100, Dr. David Alan Gilbert (git) wrote: > > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > > > When postcopy calls qemu_savevm_state_complete it's not really > > the end of migration, so skip: > > a) Finishing postcopiable iterative devices - they'll carry on > > b) The termination byte on the end of the stream. > > > > We then also add: > > qemu_savevm_state_postcopy_complete > > which is called at the end of a postcopy migration to call the > > complete methods on devices skipped in the _complete call. > > So, we should probably rename qemu_savevm_state_complete() to reflect > the fact that it's no longer actually a completion, but just the > transition from pre-copy to post-copy phases. A good, brief name > doesn't immediately occur to me, unfortunately. Well it's still completion in the non-postcopy case; if you do think of a good obvious name then I'd be happy to change it. (Another way would be to add aparameter to qemu_savevm_state_complete to make it do one or the other, but some of the conditions in it were already a bit hairy). > > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > > --- > > include/sysemu/sysemu.h | 1 + > > savevm.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++- > > 2 files changed, 52 insertions(+), 1 deletion(-) > > > > diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h > > index e7ff3d0..46665ce 100644 > > --- a/include/sysemu/sysemu.h > > +++ b/include/sysemu/sysemu.h > > @@ -113,6 +113,7 @@ void qemu_savevm_state_cancel(void); > > void qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size, > > uint64_t *res_non_postcopiable, > > uint64_t *res_postcopiable); > > +void qemu_savevm_state_postcopy_complete(QEMUFile *f); > > void qemu_savevm_command_send(QEMUFile *f, enum qemu_vm_cmd command, > > uint16_t len, uint8_t *data); > > void qemu_savevm_send_reqack(QEMUFile *f, uint32_t value); > > diff --git a/savevm.c b/savevm.c > > index a0cb88b..7c4541d 100644 > > --- a/savevm.c > > +++ b/savevm.c > > @@ -854,10 +854,51 @@ int qemu_savevm_state_iterate(QEMUFile *f) > > return ret; > > } > > > > +/* > > + * Calls the complete routines just for those devices that are postcopiable; > > + * causing the last few pages to be sent immediately and doing any associated > > + * cleanup. > > + * Note postcopy also calls the plain qemu_savevm_state_complete to complete > > + * all the other devices, but that happens at the point we switch to postcopy. > > + */ > > +void qemu_savevm_state_postcopy_complete(QEMUFile *f) > > +{ > > + SaveStateEntry *se; > > + int ret; > > + > > + QTAILQ_FOREACH(se, &savevm_handlers, entry) { > > + if (!se->ops || !se->ops->save_live_complete || > > + !se->ops->can_postcopy) { > > So, you check for the presence of a can_postcopy callback, but you > don't ever actually invoke it. Thanks, fixed. > > + continue; > > + } > > + if (se->ops && se->ops->is_active) { > > + if (!se->ops->is_active(se->opaque)) { > > + continue; > > + } > > + } > > + trace_savevm_section_start(se->idstr, se->section_id); > > + /* Section type */ > > + qemu_put_byte(f, QEMU_VM_SECTION_END); > > + qemu_put_be32(f, se->section_id); > > + > > + ret = se->ops->save_live_complete(f, se->opaque); > > I'm wondering if it might be clearer not to overload the > save_live_complete hook, but instead allow both "execution transition" > (old complete) and "final complete" (postcopy complete) hooks > (expecting only one to be non-NULL in most cases). Note that I only call save_live_complete once for any one device. Non-postcopied devices get done in the original loop, postcopied devices in the new ones, so from the point of view of a device it's still a complete. Dave > > -- > David Gibson | I'll have my music baroque, and my code > david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ > | _way_ _around_! > http://www.ozlabs.org/~dgibson -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h index e7ff3d0..46665ce 100644 --- a/include/sysemu/sysemu.h +++ b/include/sysemu/sysemu.h @@ -113,6 +113,7 @@ void qemu_savevm_state_cancel(void); void qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size, uint64_t *res_non_postcopiable, uint64_t *res_postcopiable); +void qemu_savevm_state_postcopy_complete(QEMUFile *f); void qemu_savevm_command_send(QEMUFile *f, enum qemu_vm_cmd command, uint16_t len, uint8_t *data); void qemu_savevm_send_reqack(QEMUFile *f, uint32_t value); diff --git a/savevm.c b/savevm.c index a0cb88b..7c4541d 100644 --- a/savevm.c +++ b/savevm.c @@ -854,10 +854,51 @@ int qemu_savevm_state_iterate(QEMUFile *f) return ret; } +/* + * Calls the complete routines just for those devices that are postcopiable; + * causing the last few pages to be sent immediately and doing any associated + * cleanup. + * Note postcopy also calls the plain qemu_savevm_state_complete to complete + * all the other devices, but that happens at the point we switch to postcopy. + */ +void qemu_savevm_state_postcopy_complete(QEMUFile *f) +{ + SaveStateEntry *se; + int ret; + + QTAILQ_FOREACH(se, &savevm_handlers, entry) { + if (!se->ops || !se->ops->save_live_complete || + !se->ops->can_postcopy) { + continue; + } + if (se->ops && se->ops->is_active) { + if (!se->ops->is_active(se->opaque)) { + continue; + } + } + trace_savevm_section_start(se->idstr, se->section_id); + /* Section type */ + qemu_put_byte(f, QEMU_VM_SECTION_END); + qemu_put_be32(f, se->section_id); + + ret = se->ops->save_live_complete(f, se->opaque); + trace_savevm_section_end(se->idstr, se->section_id); + if (ret < 0) { + qemu_file_set_error(f, ret); + return; + } + } + + qemu_savevm_send_postcopy_ram_end(f, 0 /* Good */); + qemu_put_byte(f, QEMU_VM_EOF); + qemu_fflush(f); +} + void qemu_savevm_state_complete(QEMUFile *f) { SaveStateEntry *se; int ret; + bool in_postcopy = migration_postcopy_phase(migrate_get_current()); trace_savevm_state_complete(); @@ -872,6 +913,11 @@ void qemu_savevm_state_complete(QEMUFile *f) continue; } } + if (in_postcopy && se->ops && se->ops->can_postcopy && + se->ops->can_postcopy(se->opaque)) { + DPRINTF("%s: Skipping %s in postcopy", __func__, se->idstr); + continue; + } trace_savevm_section_start(se->idstr, se->section_id); /* Section type */ qemu_put_byte(f, QEMU_VM_SECTION_END); @@ -908,7 +954,11 @@ void qemu_savevm_state_complete(QEMUFile *f) trace_savevm_section_end(se->idstr, se->section_id); } - qemu_put_byte(f, QEMU_VM_EOF); + if (!in_postcopy) { + /* Postcopy stream will still be going */ + qemu_put_byte(f, QEMU_VM_EOF); + } + qemu_fflush(f); }