This is v10 of the multifd save prototype, which improves the DIRECT I/O APIs and makes changes to the on disk format backward and forward compatible, avoiding the need to alter the QEMU_SAVE_VERSION.
This series demonstrates the DIRECT I/O friendly read/write code working by using the block-friently 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 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 (32): 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 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 | 9 + 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 | 793 ++++++++++++++---- src/qemu/qemu_saveimage.h | 71 +- 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 | 11 + 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, 1718 insertions(+), 404 deletions(-) create mode 100644 src/util/multifd-helper.c -- 2.35.3
