Based-on: <20200213132030.57757-1-quintela@redhat.com>

[v6]
- rebase to latest pull request
- move functions that read parameters to the parameters patechs (dave)
- require zstd on travis/docker/... (please review)
- rename multifd_method to multifd_compression
- improve documentation

Please review

[v5]
- rebased on top of latest pull request
- check zlib/zstd return codes in loops (denis suggestions)
- check that we do the right thing in error cases (I corrupted the
  stream, make buffers too small, etc by hand)

[v4]
- create new parameters: multifd-zlib-level & multifd-zstd-level
- use proper "conditionals" for qapi (thanks markus)
- more than half of the patches moved to the migration PULL request
  that this series are based on
- method type has moved to one int from a set of flags
- fixed all reviews comments

Please review.

[v3]
- rebased on top of upstream + previous multifd cancel series
- split multifd code into its own file (multifd.[ch])
- split zstd/zlib compression methods (multifd-zstd/zlib.c)
- use qemu module feauture to avoid ifdefs
  (my understanding is that zlib needs to be present, but
  we setup zstd only if it is not there or is disabled)
- multifd-method: none|zlib|zstd

  As far as I can see, there is no easy way to convince qapi that zstd
  option could/couldn't be there depending on compliation flags. I
  ended just checking in migrate_parameters_check() if it is enabled
  and giving an error message otherwise.

Questions:
- I am "reusing" the compress-level parameter for both zstd and zlib,
  but it poses a problem:
  * zlib values: 1-9 (default: 6?)
  * zstd values: 1-19 (default: 3)
So, what should I do:
  * create multifd-zstd-level and multifd-zlib-level (easier)
  * reuse compress-level, and change its maximum values depending on
    multifd-method
  * any other good option?

Please, review.

[v2] - rebase on top of previous arguments posted to the list -
introduces zlib compression - introduces zstd compression

Please help if you know anything about zstd/zlib compression.

This puts compression on top of multifd. Advantages about current
compression:

- We copy all pages in a single packet and then compress the whole
  thing.

- We reuse the compression stream for all the packets sent through the
  same channel.

- We can select nocomp/zlib/zstd levels of compression.

Please, review.

Juan Quintela (8):
  multifd: Add multifd-compression parameter
  migration: Add support for modules
  multifd: Make no compression operations into its own structure
  multifd: Add multifd-zlib-level parameter
  multifd: Add zlib compression multifd support
  configure: Enable test and libs for zstd
  multifd: Add multifd-zstd-level parameter
  multifd: Add zstd compression multifd support

 .gitlab-ci.yml                                |   1 +
 .travis.yml                                   |   1 +
 configure                                     |  30 ++
 hw/core/qdev-properties.c                     |  13 +
 include/hw/qdev-properties.h                  |   4 +
 include/qemu/module.h                         |   2 +
 migration/Makefile.objs                       |   2 +
 migration/migration.c                         |  70 ++++
 migration/migration.h                         |   3 +
 migration/multifd-zlib.c                      | 325 +++++++++++++++++
 migration/multifd-zstd.c                      | 339 ++++++++++++++++++
 migration/multifd.c                           | 191 +++++++++-
 migration/multifd.h                           |  31 ++
 migration/ram.c                               |   2 +-
 monitor/hmp-cmds.c                            |  21 ++
 qapi/migration.json                           |  80 ++++-
 tests/docker/dockerfiles/centos7.docker       |   3 +-
 .../dockerfiles/fedora-i386-cross.docker      |   3 +-
 tests/docker/dockerfiles/fedora.docker        |   3 +-
 tests/docker/dockerfiles/ubuntu.docker        |   1 +
 tests/docker/dockerfiles/ubuntu1804.docker    |   1 +
 tests/qtest/migration-test.c                  |  30 +-
 tests/vm/fedora                               |   5 +-
 tests/vm/freebsd                              |   3 +
 tests/vm/netbsd                               |   3 +
 tests/vm/openbsd                              |   3 +
 vl.c                                          |   1 +
 27 files changed, 1151 insertions(+), 20 deletions(-)
 create mode 100644 migration/multifd-zlib.c
 create mode 100644 migration/multifd-zstd.c

-- 
2.24.1