Re: [Qemu-devel] [PATCH v5 14/45] Move loadvm_handlers into MigrationIncomingState

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* David Gibson (david@gibson.dropbear.id.au) wrote:
> On Wed, Feb 25, 2015 at 04:51:37PM +0000, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> > 
> > In postcopy we need the loadvm_handlers to be used in a couple
> > of different instances of the loadvm loop/routine, and thus
> > it can't be local any more.
> > 
> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > ---
> >  include/migration/migration.h |  5 +++++
> >  include/migration/vmstate.h   |  2 ++
> >  include/qemu/typedefs.h       |  1 +
> >  migration/migration.c         |  2 ++
> >  savevm.c                      | 28 ++++++++++++++++------------
> >  5 files changed, 26 insertions(+), 12 deletions(-)
> > 
> > diff --git a/include/migration/migration.h b/include/migration/migration.h
> > index 3776e86..751caa0 100644
> > --- a/include/migration/migration.h
> > +++ b/include/migration/migration.h
> > @@ -50,10 +50,15 @@ enum mig_rpcomm_cmd {
> >  
> >  typedef struct MigrationState MigrationState;
> >  
> > +typedef QLIST_HEAD(, LoadStateEntry) LoadStateEntry_Head;
> > +
> >  /* State for the incoming migration */
> >  struct MigrationIncomingState {
> >      QEMUFile *file;
> >  
> > +    /* See savevm.c */
> > +    LoadStateEntry_Head loadvm_handlers;
> > +
> >      QEMUFile *return_path;
> >      QemuMutex      rp_mutex;    /* We send replies from multiple threads */
> >  };
> > diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
> > index c20f2d1..18da207 100644
> > --- a/include/migration/vmstate.h
> > +++ b/include/migration/vmstate.h
> > @@ -797,6 +797,8 @@ extern const VMStateInfo vmstate_info_bitmap;
> >  
> >  #define SELF_ANNOUNCE_ROUNDS 5
> >  
> > +void loadvm_free_handlers(MigrationIncomingState *mis);
> > +
> >  int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
> >                         void *opaque, int version_id);
> >  void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
> > diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
> > index 74dfad3..6fdcbcd 100644
> > --- a/include/qemu/typedefs.h
> > +++ b/include/qemu/typedefs.h
> > @@ -31,6 +31,7 @@ typedef struct I2CBus I2CBus;
> >  typedef struct I2SCodec I2SCodec;
> >  typedef struct ISABus ISABus;
> >  typedef struct ISADevice ISADevice;
> > +typedef struct LoadStateEntry LoadStateEntry;
> >  typedef struct MACAddr MACAddr;
> >  typedef struct MachineClass MachineClass;
> >  typedef struct MachineState MachineState;
> > diff --git a/migration/migration.c b/migration/migration.c
> > index 34cd4fe..4592060 100644
> > --- a/migration/migration.c
> > +++ b/migration/migration.c
> > @@ -78,6 +78,7 @@ MigrationIncomingState *migration_incoming_state_new(QEMUFile* f)
> >  {
> >      mis_current = g_malloc0(sizeof(MigrationIncomingState));
> >      mis_current->file = f;
> > +    QLIST_INIT(&mis_current->loadvm_handlers);
> >      qemu_mutex_init(&mis_current->rp_mutex);
> >  
> >      return mis_current;
> > @@ -85,6 +86,7 @@ MigrationIncomingState *migration_incoming_state_new(QEMUFile* f)
> >  
> >  void migration_incoming_state_destroy(void)
> >  {
> > +    loadvm_free_handlers(mis_current);
> 
> AFAICT this is the only caler of loadvm_free_handlers(), so why not
> just open-code it here?

I was keeping this handler list as owned by savevm.c; all it's allocation
and it's use are done in savevm.c, so it would seem odd to open code
freeing the list in a separate file.

> >      g_free(mis_current);
> >      mis_current = NULL;
> >  }
> > diff --git a/savevm.c b/savevm.c
> > index 7084d07..f42713d 100644
> > --- a/savevm.c
> > +++ b/savevm.c
> > @@ -1019,18 +1019,26 @@ static int loadvm_process_command(QEMUFile *f)
> >      return 0;
> >  }
> >  
> > -typedef struct LoadStateEntry {
> > +struct LoadStateEntry {
> 
> Why remove the typedef?

Because it is now typedef'd in typedefs.h, and older gcc (RHEL6)
object to two typedefs even if they're of the same thing.

Dave

> >      QLIST_ENTRY(LoadStateEntry) entry;
> >      SaveStateEntry *se;
> >      int section_id;
> >      int version_id;
> > -} LoadStateEntry;
> > +};
> >  
> > -int qemu_loadvm_state(QEMUFile *f)
> > +void loadvm_free_handlers(MigrationIncomingState *mis)
> >  {
> > -    QLIST_HEAD(, LoadStateEntry) loadvm_handlers =
> > -        QLIST_HEAD_INITIALIZER(loadvm_handlers);
> >      LoadStateEntry *le, *new_le;
> > +
> > +    QLIST_FOREACH_SAFE(le, &mis->loadvm_handlers, entry, new_le) {
> > +        QLIST_REMOVE(le, entry);
> > +        g_free(le);
> > +    }
> > +}
> > +
> > +int qemu_loadvm_state(QEMUFile *f)
> > +{
> > +    MigrationIncomingState *mis = migration_incoming_get_current();
> >      Error *local_err = NULL;
> >      uint8_t section_type;
> >      unsigned int v;
> > @@ -1061,6 +1069,7 @@ int qemu_loadvm_state(QEMUFile *f)
> >      while ((section_type = qemu_get_byte(f)) != QEMU_VM_EOF) {
> >          uint32_t instance_id, version_id, section_id;
> >          SaveStateEntry *se;
> > +        LoadStateEntry *le;
> >          char idstr[256];
> >  
> >          trace_qemu_loadvm_state_section(section_type);
> > @@ -1102,7 +1111,7 @@ int qemu_loadvm_state(QEMUFile *f)
> >              le->se = se;
> >              le->section_id = section_id;
> >              le->version_id = version_id;
> > -            QLIST_INSERT_HEAD(&loadvm_handlers, le, entry);
> > +            QLIST_INSERT_HEAD(&mis->loadvm_handlers, le, entry);
> >  
> >              ret = vmstate_load(f, le->se, le->version_id);
> >              if (ret < 0) {
> > @@ -1116,7 +1125,7 @@ int qemu_loadvm_state(QEMUFile *f)
> >              section_id = qemu_get_be32(f);
> >  
> >              trace_qemu_loadvm_state_section_partend(section_id);
> > -            QLIST_FOREACH(le, &loadvm_handlers, entry) {
> > +            QLIST_FOREACH(le, &mis->loadvm_handlers, entry) {
> >                  if (le->section_id == section_id) {
> >                      break;
> >                  }
> > @@ -1152,11 +1161,6 @@ int qemu_loadvm_state(QEMUFile *f)
> >      ret = 0;
> >  
> >  out:
> > -    QLIST_FOREACH_SAFE(le, &loadvm_handlers, entry, new_le) {
> > -        QLIST_REMOVE(le, entry);
> > -        g_free(le);
> > -    }
> > -
> >      if (ret == 0) {
> >          ret = qemu_file_get_error(f);
> >      }
> 
> -- 
> 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