diff options
Diffstat (limited to 'migration/options.c')
| -rw-r--r-- | migration/options.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/migration/options.c b/migration/options.c index 5ab5b6d85d..645f55003d 100644 --- a/migration/options.c +++ b/migration/options.c @@ -702,6 +702,25 @@ bool migrate_cpu_throttle_tailslow(void) return s->parameters.cpu_throttle_tailslow; } +bool migrate_direct_io(void) +{ + MigrationState *s = migrate_get_current(); + + /* + * O_DIRECT is only supported with mapped-ram and multifd. + * + * mapped-ram is needed because filesystems impose restrictions on + * O_DIRECT IO alignment (see MAPPED_RAM_FILE_OFFSET_ALIGNMENT). + * + * multifd is needed to keep the unaligned portion of the stream + * isolated to the main migration thread while multifd channels + * process the aligned data with O_DIRECT enabled. + */ + return s->parameters.direct_io && + s->capabilities[MIGRATION_CAPABILITY_MAPPED_RAM] && + s->capabilities[MIGRATION_CAPABILITY_MULTIFD]; +} + uint64_t migrate_downtime_limit(void) { MigrationState *s = migrate_get_current(); @@ -905,6 +924,8 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp) params->mode = s->parameters.mode; params->has_zero_page_detection = true; params->zero_page_detection = s->parameters.zero_page_detection; + params->has_direct_io = true; + params->direct_io = s->parameters.direct_io; return params; } @@ -937,6 +958,7 @@ void migrate_params_init(MigrationParameters *params) params->has_vcpu_dirty_limit = true; params->has_mode = true; params->has_zero_page_detection = true; + params->has_direct_io = true; } /* @@ -1110,6 +1132,11 @@ bool migrate_params_check(MigrationParameters *params, Error **errp) return false; } + if (params->has_direct_io && params->direct_io && !qemu_has_direct_io()) { + error_setg(errp, "No build-time support for direct-io"); + return false; + } + return true; } @@ -1216,6 +1243,10 @@ static void migrate_params_test_apply(MigrateSetParameters *params, if (params->has_zero_page_detection) { dest->zero_page_detection = params->zero_page_detection; } + + if (params->has_direct_io) { + dest->direct_io = params->direct_io; + } } static void migrate_params_apply(MigrateSetParameters *params, Error **errp) @@ -1341,6 +1372,10 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp) if (params->has_zero_page_detection) { s->parameters.zero_page_detection = params->zero_page_detection; } + + if (params->has_direct_io) { + s->parameters.direct_io = params->direct_io; + } } void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp) |