[libvirt RFCv9 00/31] multifd save restore prototype

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This is v9 of the multifd save prototype, which splits things up
more in order to hopefully offer more upstreamable code,

and adds DIRECT I/O APIs and changes to the save/restore format
to be more block friendly, potentially removing the need of an
iohelper completely.

This is demonstrated in this case using the multifd streams supplied by
the multifd helper, but could also work with block-aware QEMU streams
if ever available in the future.

KNOWN ISSUES:

a) still applies only to save/restore (no managed save etc)
b) multifd: saves to multiple files instead of just one file

---

changes from v8:

* rebased on master

* reordered patches to add more upstreamable content at the start

* split introduction of virQEMUSaveFd, so the first part is multifd-free

* new virQEMUSaveDataRead as a mirror of virQEMUSaveDataWrite

* introduced virFileDirect API, using it in virFileDisk operations and
  for virQEMUSaveRead and virQEMUSaveWrite

---

changes from v7:

* [ base params API and iohelper refactoring upstreamed ]

* extended the QEMU save image format more, to record the nr
  of multifd channels on save. Made the data header struct packed.

* removed --parallel-connections from the restore command, as now
  it is useless due to QEMU save image format extension.

* separate out patches to expose migration_params APIs to saveimage,
  including qemuMigrationParamsSetString, SetCap, SetInt.

* fixed bugs in the ImageOpen patch (missing saveFd init), removed
  some whitespace, and fixed some convoluted code paths for return
  value -3.

---

changes from v6:

* improved error path handling, with error messages and especially
  cancellation of qemu process on error during restore.

* split patches more and reordered them to keep general refactoring
  at the beginning before the --parallel stuff is introduced.

* improved multifd compression support, including adding an enum
  and extending the QEMU save image format to record the compression
  used on save, and pick it up automatically on restore.

---

changes from v4:

* runIO renamed to virFileDiskCopy and rethought arguments

* renamed new APIs from ...ParametersFlags to ...Params

* introduce the new virDomainSaveParams and virDomainRestoreParams
  without any additional parameters, so they can be upstreamed first.

* solved the issue in the gendispatch.pl script generating code that
  was missing the conn parameter.

---

changes from v3:

* reordered series to have all helper-related change at the start

* solved all reported issues from ninja test, including documentation

* fixed most broken migration capabilities code (still imperfect likely)

* added G_GNUC_UNUSED as needed

* after multifd restore, added what I think were the missing operations:

  qemuProcessRefreshState(),
  qemuProcessStartCPUs() - most importantly,
  virDomainObjSave()

  The domain now starts running after restore without further encouragement

* removed the sleep(10) from the multifd-helper

---

changes from v2:

* added ability to restore the VM from disk using multifd

* fixed the multifd-helper to work in both directions,
  assuming the need to listen for save, and connect for restore.

* fixed a large number of bugs, and probably introduced some :-)

---

Claudio Fontana (31):
  virfile: introduce virFileDirect APIs
  virfile: use virFileDirect API in runIOCopy
  qemu: saveimage: rework save format and read/write to be O_DIRECT
    friendly
  virfile: virFileDiskCopy: prepare for O_DIRECT files without wrapper
  qemu: saveimage: introduce virQEMUSaveFd
  qemu: saveimage: convert qemuSaveImageCreate to use virQEMUSaveFd
  qemu: saveimage: convert qemuSaveImageOpen to use virQEMUSaveFd
  tools: prepare doSave to use parameters
  tools: prepare cmdRestore to use parameters
  libvirt: add new VIR_DOMAIN_SAVE_PARALLEL flag and parameter
  qemu: add stub support for VIR_DOMAIN_SAVE_PARALLEL in save
  qemu: add stub support for VIR_DOMAIN_SAVE_PARALLEL in restore
  multifd-helper: new helper for parallel save/restore
  qemu: saveimage: add virQEMUSaveFd APIs for multifd
  qemu: saveimage: wire up saveimage code with the multifd helper
  qemu: capabilities: add multifd to the probed migration capabilities
  qemu: saveimage: add multifd related fields to save format
  qemu: migration_params: add APIs to set Int and Cap
  qemu: migration: implement qemuMigrationSrcToFilesMultiFd for save
  qemu: add parameter to qemuMigrationDstRun to skip waiting
  qemu: implement qemuSaveImageLoadMultiFd for restore
  tools: add parallel parameter to virsh save command
  tools: add parallel parameter to virsh restore command
  qemu: add migration parameter multifd-compression
  libvirt: add new VIR_DOMAIN_SAVE_PARAM_PARALLEL_COMPRESSION
  qemu: saveimage: add parallel compression argument to ImageCreate
  qemu: saveimage: add stub support for multifd compression parameter
  qemu: migration: expose qemuMigrationParamsSetString
  qemu: saveimage: implement multifd-compression in parallel save
  qemu: saveimage: restore compressed parallel images
  tools: add parallel-compression parameter to virsh save command

 docs/manpages/virsh.rst                       |  39 +-
 include/libvirt/libvirt-domain.h              |  29 +
 po/POTFILES.in                                |   1 +
 src/libvirt_private.syms                      |   7 +
 src/qemu/qemu_capabilities.c                  |   4 +
 src/qemu/qemu_capabilities.h                  |   2 +
 src/qemu/qemu_driver.c                        | 146 ++--
 src/qemu/qemu_migration.c                     | 160 ++--
 src/qemu/qemu_migration.h                     |  16 +-
 src/qemu/qemu_migration_params.c              |  71 +-
 src/qemu/qemu_migration_params.h              |  15 +
 src/qemu/qemu_process.c                       |   3 +-
 src/qemu/qemu_process.h                       |   5 +-
 src/qemu/qemu_saveimage.c                     | 753 +++++++++++++-----
 src/qemu/qemu_saveimage.h                     |  73 +-
 src/qemu/qemu_snapshot.c                      |   6 +-
 src/util/meson.build                          |  16 +
 src/util/multifd-helper.c                     | 247 ++++++
 src/util/virfile.c                            | 316 +++++++-
 src/util/virfile.h                            |  10 +
 src/util/virthread.c                          |   5 +
 src/util/virthread.h                          |   1 +
 .../caps_4.0.0.aarch64.xml                    |   1 +
 .../qemucapabilitiesdata/caps_4.0.0.ppc64.xml |   1 +
 .../caps_4.0.0.riscv32.xml                    |   1 +
 .../caps_4.0.0.riscv64.xml                    |   1 +
 .../qemucapabilitiesdata/caps_4.0.0.s390x.xml |   1 +
 .../caps_4.0.0.x86_64.xml                     |   1 +
 .../caps_4.1.0.x86_64.xml                     |   1 +
 .../caps_4.2.0.aarch64.xml                    |   1 +
 .../qemucapabilitiesdata/caps_4.2.0.ppc64.xml |   1 +
 .../qemucapabilitiesdata/caps_4.2.0.s390x.xml |   1 +
 .../caps_4.2.0.x86_64.xml                     |   1 +
 .../caps_5.0.0.aarch64.xml                    |   2 +
 .../qemucapabilitiesdata/caps_5.0.0.ppc64.xml |   2 +
 .../caps_5.0.0.riscv64.xml                    |   2 +
 .../caps_5.0.0.x86_64.xml                     |   2 +
 .../qemucapabilitiesdata/caps_5.1.0.sparc.xml |   2 +
 .../caps_5.1.0.x86_64.xml                     |   2 +
 .../caps_5.2.0.aarch64.xml                    |   2 +
 .../qemucapabilitiesdata/caps_5.2.0.ppc64.xml |   2 +
 .../caps_5.2.0.riscv64.xml                    |   2 +
 .../qemucapabilitiesdata/caps_5.2.0.s390x.xml |   2 +
 .../caps_5.2.0.x86_64.xml                     |   2 +
 .../caps_6.0.0.aarch64.xml                    |   2 +
 .../qemucapabilitiesdata/caps_6.0.0.s390x.xml |   2 +
 .../caps_6.0.0.x86_64.xml                     |   2 +
 .../caps_6.1.0.x86_64.xml                     |   2 +
 .../caps_6.2.0.aarch64.xml                    |   2 +
 .../qemucapabilitiesdata/caps_6.2.0.ppc64.xml |   2 +
 .../caps_6.2.0.x86_64.xml                     |   2 +
 .../caps_7.0.0.aarch64.xml                    |   2 +
 .../qemucapabilitiesdata/caps_7.0.0.ppc64.xml |   2 +
 .../caps_7.0.0.x86_64.xml                     |   2 +
 .../caps_7.1.0.x86_64.xml                     |   2 +
 tools/virsh-domain.c                          | 101 ++-
 56 files changed, 1675 insertions(+), 406 deletions(-)
 create mode 100644 src/util/multifd-helper.c

-- 
2.35.3





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