Re: [PATCH v4 22/23] migration: Use multifd before we check for the zero page
"Dr. David Alan Gilbert" wrote:
> * Juan Quintela (quint...@redhat.com) wrote:
>> So we use multifd to transmit zero pages.
>>
>> Signed-off-by: Juan Quintela
>> ---
>> migration/ram.c | 32 +++-
>> 1 file changed, 31 insertions(+), 1 deletion(-)
>>
>> diff --git a/migration/ram.c b/migration/ram.c
>> index 3536778e19..bdc7cec4cd 100644
>> --- a/migration/ram.c
>> +++ b/migration/ram.c
>> @@ -2168,6 +2168,32 @@ static int ram_save_target_page_legacy(RAMState *rs,
>> PageSearchStatus *pss)
>> return ram_save_page(rs, pss);
>> }
>>
>> +/**
>> + * ram_save_target_page_multifd: save one target page
>> + *
>> + * Returns the number of pages written
>> + *
>> + * @rs: current RAM state
>> + * @pss: data about the page we want to send
>> + */
>> +static int ram_save_target_page_multifd(RAMState *rs, PageSearchStatus *pss)
>> +{
>> +RAMBlock *block = pss->block;
>> +ram_addr_t offset = ((ram_addr_t)pss->page) << TARGET_PAGE_BITS;
>> +int res;
>> +
>> +if (!migration_in_postcopy()) {
>> +return ram_save_multifd_page(rs, block, offset);
>> +}
>> +
>> +res = save_zero_page(rs, block, offset);
>
> I'm confused; I think I was expecting to see in this patch, the one that
> would check the parameter you added and do something different - where
> did that go?
>
> Note I think this is quite subtle that the difference here is really
> just the ordering rather than adding a zero page test.
Hi dave
you are right. Too much rebasing.
>> +if (res > 0) {
>> +return res;
>> +}
>> +
>> +return ram_save_page(rs, pss);
>> +}
>> +
>> /**
>> * ram_save_host_page: save a whole host page
>> *
>> @@ -3011,7 +3037,11 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
>> ram_control_before_iterate(f, RAM_CONTROL_SETUP);
>> ram_control_after_iterate(f, RAM_CONTROL_SETUP);
>>
>> -(*rsp)->ram_save_target_page = ram_save_target_page_legacy;
>> +if (migrate_use_multifd()) {
>> +(*rsp)->ram_save_target_page = ram_save_target_page_multifd;
>> +} else {
>> +(*rsp)->ram_save_target_page = ram_save_target_page_legacy;
>> +}
I need to add the check here.
Good catch, Juan.
>> multifd_send_sync_main(f);
>> qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
>> qemu_fflush(f);
>> --
>> 2.34.1
>>
Re: [PATCH v4 22/23] migration: Use multifd before we check for the zero page
* Juan Quintela (quint...@redhat.com) wrote:
> So we use multifd to transmit zero pages.
>
> Signed-off-by: Juan Quintela
> ---
> migration/ram.c | 32 +++-
> 1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index 3536778e19..bdc7cec4cd 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2168,6 +2168,32 @@ static int ram_save_target_page_legacy(RAMState *rs,
> PageSearchStatus *pss)
> return ram_save_page(rs, pss);
> }
>
> +/**
> + * ram_save_target_page_multifd: save one target page
> + *
> + * Returns the number of pages written
> + *
> + * @rs: current RAM state
> + * @pss: data about the page we want to send
> + */
> +static int ram_save_target_page_multifd(RAMState *rs, PageSearchStatus *pss)
> +{
> +RAMBlock *block = pss->block;
> +ram_addr_t offset = ((ram_addr_t)pss->page) << TARGET_PAGE_BITS;
> +int res;
> +
> +if (!migration_in_postcopy()) {
> +return ram_save_multifd_page(rs, block, offset);
> +}
> +
> +res = save_zero_page(rs, block, offset);
I'm confused; I think I was expecting to see in this patch, the one that
would check the parameter you added and do something different - where
did that go?
Note I think this is quite subtle that the difference here is really
just the ordering rather than adding a zero page test.
Dave
> +if (res > 0) {
> +return res;
> +}
> +
> +return ram_save_page(rs, pss);
> +}
> +
> /**
> * ram_save_host_page: save a whole host page
> *
> @@ -3011,7 +3037,11 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
> ram_control_before_iterate(f, RAM_CONTROL_SETUP);
> ram_control_after_iterate(f, RAM_CONTROL_SETUP);
>
> -(*rsp)->ram_save_target_page = ram_save_target_page_legacy;
> +if (migrate_use_multifd()) {
> +(*rsp)->ram_save_target_page = ram_save_target_page_multifd;
> +} else {
> +(*rsp)->ram_save_target_page = ram_save_target_page_legacy;
> +}
> multifd_send_sync_main(f);
> qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
> qemu_fflush(f);
> --
> 2.34.1
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
