5:19 p.m.
This is v11 of the multifd save prototype, which focuses on saving
to a single file instead of requiring multiple separate files for
multifd channels.
This series demonstrates a way to save and restore from a single file
by using interleaved channels of a size equal to the transfer buffer
size (1MB), and relying on UNIX holes to avoid wasting physical disk
space due to channels of different size.
KNOWN ISSUES:
a) still applies only to save/restore (no managed save etc)
b) this is not not done in QEMU, where it could be possible to teach
QEMU to migrate directly to a file or block device in a
block-aligned way by altering the migration stream code and the
state migration code of all devices.
changes from v10:
* virfile: add new API virFileDiskCopyChannel, which extends the
existing virFileDiskCopy to work with parallel channels in the file.
* drop use of virthread API, use GLIB for threads.
* pass only a single FD to the multifd-helper, which will then open
additional FDs as required for the multithreaded I/O.
* simplify virQEMUSaveFd API, separating the initialization from the
addition of extra channels.
* adapt all documentation to mention a single file instead of multiple.
* remove the "Lim" versions of virFileDirectRead and Write, they are
not needed.
---
changes from v9:
* exposed virFileDirectAlign
* separated the >= 2 QEMU_SAVE_VERSION change in own patch
* reworked the write code to add the alignment padding to the
data_len, making the on disk format compatible when loaded
from an older libvirt.
* reworked the read code to use direct I/O APIs only for actual
direct I/O file descriptors, so as to make old images work
with newer libvirt.
---
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 (33):
virfile: introduce virFileDirect APIs
virfile: use virFileDirect API in runIOCopy
qemu: saveimage: rework image read/write to be O_DIRECT friendly
qemu: saveimage: assume future formats will also support compression
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
virfile: add new API virFileDiskCopyChannel
multifd-helper: new helper for parallel save/restore
qemu: saveimage: update virQEMUSaveFd struct for parallel save
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 | 26 +-
include/libvirt/libvirt-domain.h | 24 +
po/POTFILES | 1 +
src/libvirt_private.syms | 6 +
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 | 703 +++++++++++++-----
src/qemu/qemu_saveimage.h | 69 +-
src/qemu/qemu_snapshot.c | 6 +-
src/util/iohelper.c | 3 +
src/util/meson.build | 16 +
src/util/multifd-helper.c | 359 +++++++++
src/util/virfile.c | 391 +++++++---
src/util/virfile.h | 11 +
.../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 ++-
55 files changed, 1748 insertions(+), 445 deletions(-)
create mode 100644 src/util/multifd-helper.c
--
2.26.2