motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-02 07:13:54 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

migration: Add direct-io parameter

Browse source 
Add the direct-io migration parameter that tells the migration code to
use O_DIRECT when opening the migration stream file whenever possible.

This is currently only used with the mapped-ram migration that has a
clear window guaranteed to perform aligned writes.

Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
This commit is contained in:
Fabiano Rosas 2024-06-17 15:57:26 -03:00
parent 46cec74c1b
commit b43b61d5be
6 changed files with 76 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

35
migration/options.c
View file

@ -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)