> On 16 Oct 2026, at 6:37 PM, Jiri Denemark <[email protected]> wrote: > > !-------------------------------------------------------------------| > CAUTION: External Email > > |-------------------------------------------------------------------! > > On Thu, Sep 17, 2026 at 06:20:29 +0000, Tejus GK wrote: >> QEMU supports a migration parameter to determine whether zero-page >> checking should be performed and if yes, where it should be performed >> (i.e., in the main migration thread or multifd threads). Add support for >> this parameter in libvirt. >> >> Signed-off-by: Tejus GK <[email protected]> >> --- >> include/libvirt/libvirt-domain.h | 11 +++++++++++ >> src/qemu/qemu_migration.c | 1 + >> src/qemu/qemu_migration_params.c | 8 ++++++++ >> src/qemu/qemu_migration_params.h | 1 + >> tools/virsh-domain.c | 13 +++++++++++++ >> 5 files changed, 34 insertions(+) >> >> diff --git a/include/libvirt/libvirt-domain.h >> b/include/libvirt/libvirt-domain.h >> index 99208137c3..5a4875770b 100644 >> --- a/include/libvirt/libvirt-domain.h >> +++ b/include/libvirt/libvirt-domain.h >> @@ -1468,6 +1468,17 @@ typedef enum { >> */ >> # define VIR_MIGRATE_PARAM_TLS_DESTINATION "tls.destination" >> >> +/** >> + * VIR_MIGRATE_PARAM_ZERO_PAGE_DETECTION: >> + * >> + * virDomainMigrate* params field: zero page detection method as >> + * VIR_TYPED_PARAM_STRING. Supported values are 'none', 'legacy', and >> + * 'multifd'. >> + * >> + * Since: 12.8.0 >> + */ >> +# define VIR_MIGRATE_PARAM_ZERO_PAGE_DETECTION "zero_page_detection" >> + > > Historically zero page detection has always been performed and it was > done in the main thread. Which is what is happening when this parameter > is not set as QEMU defaults to "legacy". Given that the "multifd" value > fallbacks to "legacy" if multifd migration is not enabled and that I > can't think of a reason to disable the detection completely, I think > should just always set this parameter to "multifd" when QEMU is new > enough to support it. > > That said, if for some reason we'd want to allow users to > disable zero page detection, we should do it via a boolean parameter > that would select between "none" and "multifd" as there's no reason for > exposing "legacy" > > Jirka
Hi Jiri, thank you for the review! I’ll respin this patch by changing the param to a boolean one instead, and send a V2 shortly. regards, tejus
