Re: [Qemu-devel] [PATCH 2/2] savevm: Add new helpers to process the different stages of loadvm/savevm

[Hailiang Zhang <zhang.zhanghailiang@huawei.com>]

On 2017/1/31 18:05, Dr. David Alan Gilbert wrote:
> * zhanghailiang (zhang.zhanghailiang@huawei.com) wrote:
>> There are several stages during loadvm/savevm process. In different stage,
>> migration incoming processes different types of sections.
>> We want to control these stages more accuracy, it will benefit COLO
>> performance, we don't have to save type of QEMU_VM_SECTION_START
>> sections everytime while do checkpoint, besides, we want to separate
>> the process of saving/loading memory and devices state.
>>
>> So we add three new helper functions: qemu_loadvm_state_begin(),
>> qemu_load_device_state() and qemu_savevm_live_state() to achieve
>> different process during migration.
>>
>> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
>> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>
> I don't think this one can go in without the patch that follows which
> uses these functions; we don't normally add functions
> without the patch that uses them.
>

Yes, this series is prerequisite for the later COLO optimization,
that will be a bigger series, that's why i picked these two patches,
but since it is irrational, I'll post these series with the later one
where we use this functions. Thanks. :)

> Dave
>
>> ---
>>   include/sysemu/sysemu.h |  4 ++++
>>   migration/savevm.c      | 41 +++++++++++++++++++++++++++++++++++++++++
>>   2 files changed, 45 insertions(+)
>>
>> diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
>> index ff8ffb5..d9214bf 100644
>> --- a/include/sysemu/sysemu.h
>> +++ b/include/sysemu/sysemu.h
>> @@ -126,7 +126,11 @@ void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name,
>>                                              uint64_t *start_list,
>>                                              uint64_t *length_list);
>>
>> +void qemu_savevm_live_state(QEMUFile *f);
>> +
>>   int qemu_loadvm_state(QEMUFile *f);
>> +int qemu_loadvm_state_begin(QEMUFile *f);
>> +int qemu_load_device_state(QEMUFile *f);
>>
>>   extern int autostart;
>>
>> diff --git a/migration/savevm.c b/migration/savevm.c
>> index 92b3d6c..04dee4f 100644
>> --- a/migration/savevm.c
>> +++ b/migration/savevm.c
>> @@ -1264,6 +1264,13 @@ done:
>>       return ret;
>>   }
>>
>> +void qemu_savevm_live_state(QEMUFile *f)
>> +{
>> +    /* save QEMU_VM_SECTION_END section */
>> +    qemu_savevm_state_complete_precopy(f, true);
>> +    qemu_put_byte(f, QEMU_VM_EOF);
>> +}
>> +
>>   static int qemu_save_device_state(QEMUFile *f)
>>   {
>>       SaveStateEntry *se;
>> @@ -2064,6 +2071,40 @@ int qemu_loadvm_state(QEMUFile *f)
>>       return ret;
>>   }
>>
>> +int qemu_loadvm_state_begin(QEMUFile *f)
>> +{
>> +    MigrationIncomingState *mis = migration_incoming_get_current();
>> +    Error *local_err = NULL;
>> +    int ret;
>> +
>> +    if (qemu_savevm_state_blocked(&local_err)) {
>> +        error_report_err(local_err);
>> +        return -EINVAL;
>> +    }
>> +    /* Load QEMU_VM_SECTION_START section */
>> +    ret = qemu_loadvm_state_main(f, mis);
>> +    if (ret < 0) {
>> +        error_report("Failed to loadvm begin work: %d", ret);
>> +    }
>> +    return ret;
>> +}
>> +
>> +int qemu_load_device_state(QEMUFile *f)
>> +{
>> +    MigrationIncomingState *mis = migration_incoming_get_current();
>> +    int ret;
>> +
>> +    /* Load QEMU_VM_SECTION_FULL section */
>> +    ret = qemu_loadvm_state_main(f, mis);
>> +    if (ret < 0) {
>> +        error_report("Failed to load device state: %d", ret);
>> +        return ret;
>> +    }
>> +
>> +    cpu_synchronize_all_post_init();
>> +    return 0;
>> +}
>> +
>>   void hmp_savevm(Monitor *mon, const QDict *qdict)
>>   {
>>       BlockDriverState *bs, *bs1;
>> --
>> 1.8.3.1
>>
>>
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>
> .
>