[RFC][PATCH v1 0/7] *** Add Multifd support for TLS migration ***

[Chuan Zheng <zhengchuan@huawei.com>]

TLS migration could easily reach bottleneck of cpu because of encryption
and decryption in migration thread.
In our test, the tls migration could only reach 300MB/s under bandwidth
of 500MB/s.

Inspired by multifd, we add multifd support for tls migration to make fully
use of given net bandwidth at the cost of multi-cpus and could reduce
at most of 100% migration time with 4U16G test vm.

Evaluate migration time of migration vm.
The VM specifications for migration are as follows:
- VM use 4-K page;
- the number of VCPU is 4;
- the total memory is 16Gigabit;
- use 'mempress' tool to pressurize VM(mempress 4096 100);
- migration flag is 73755 (8219 + 65536 (TLS)) vs 204827 (8219 + 65536 (TLS) + 131072(Multifd))

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
|                      |         TLS           |      MultiFD + TLS (2 channel)    |
--------------------------------------------------------t---------------------------
| mempress 1024 120    |       25.035s         |           15.067s                 |
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
| mempress 1024 200    |       48.798s         |           25.334s                 |
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
| mempress 1024 300    |   Migration Failed    |           25.617s                 |
------------------------------------------------------------------------------------

Chuan Zheng (7):
  migration/tls: save hostname into MigrationState
  migration/tls: extract migration_tls_client_create for common-use
  migration/tls: add MigrationState into MultiFDSendParams
  migration/tls: extract cleanup function for common-use
  migration/tls: add support for tls check
  migration/tls: add support for multifd tls-handshake
  migration/tls: add trace points for multifd-tls

 migration/channel.c    |   5 ++
 migration/migration.c  |   1 +
 migration/migration.h  |   5 ++
 migration/multifd.c    | 121 +++++++++++++++++++++++++++++++++++++++++++------
 migration/multifd.h    |   2 +
 migration/tls.c        |  26 +++++++----
 migration/tls.h        |   6 +++
 migration/trace-events |   5 ++
 8 files changed, 149 insertions(+), 22 deletions(-)

-- 
1.8.3.1