[Qemu-devel] Re: [PATCH 15/19] savevm: introduce qemu_savevm_trans_{begin, commit}.

[Paolo Bonzini <pbonzini@redhat.com>]

On 01/28/2011 08:21 AM, Yoshiaki Tamura wrote:
> +int qemu_savevm_trans_begin(Monitor *mon, QEMUFile *f, int init)
> +{
> +    SaveStateEntry *se;
> +    int skipped = 0;
> +
> +    QTAILQ_FOREACH(se,&savevm_handlers, entry) {
> +        int len, stage, ret;
> +
> +        if (se->save_live_state == NULL) {
> +            continue;
> +        }
> +
> +        /* Section type */
> +        qemu_put_byte(f, QEMU_VM_SECTION_START);
> +        qemu_put_be32(f, se->section_id);
> +
> +        /* ID string */
> +        len = strlen(se->idstr);
> +        qemu_put_byte(f, len);
> +        qemu_put_buffer(f, (uint8_t *)se->idstr, len);
> +
> +        qemu_put_be32(f, se->instance_id);
> +        qemu_put_be32(f, se->version_id);
> +
> +        stage = init ? QEMU_VM_SECTION_START : QEMU_VM_SECTION_PART;
> +        ret = se->save_live_state(mon, f, stage, se->opaque);
> +        if (!ret) {
> +            skipped++;
> +        }
> +    }
> +
> +    if (qemu_file_has_error(f)) {
> +        return -EIO;
> +    }
> +
> +    return skipped;
> +}
> +

Right now, this is very similar to qemu_savevm_state_begin and _iterate, 
but not quite.  Perhaps you could abstract it to a single function that 
could be used everywhere live handlers are used.  For example,

/* section says which header to write; incremental == true forces to
    pass SECTION_PART instead of SECTION_START. In code:

if (section == QEMU_VM_SECTION_START) {
     stage = incremental ? QEMU_VM_SECTION_PART : QEMU_VM_SECTION_START;
} else {
     assert(incremental);
     stage = section;
}

    */
int qemu_savevm_state_live(Monitor *mon, QEMUFile *f, int section,
			   int incremental)

Likewise,

> +    QTAILQ_FOREACH(se, &savevm_handlers, entry) {
> +        int len;
> +
> +        if (se->save_state == NULL && se->vmsd == NULL) {
> +            continue;
> +        }
> +
> +        /* Section type */
> +        qemu_put_byte(f, QEMU_VM_SECTION_FULL);
> +        qemu_put_be32(f, se->section_id);
> +
> +        /* ID string */
> +        len = strlen(se->idstr);
> +        qemu_put_byte(f, len);
> +        qemu_put_buffer(f, (uint8_t *)se->idstr, len);
> +
> +        qemu_put_be32(f, se->instance_id);
> +        qemu_put_be32(f, se->version_id);
> +
> +        vmstate_save(f, se);
> +    }

this code is straight from qemu_savevm_state_complete and should be 
moved into its own function.

Paolo