From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53550) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4o5n-0006WU-5W for qemu-devel@nongnu.org; Tue, 16 Jun 2015 06:27:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z4o5l-0000zv-W1 for qemu-devel@nongnu.org; Tue, 16 Jun 2015 06:27:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34059) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4o5l-0000zp-PT for qemu-devel@nongnu.org; Tue, 16 Jun 2015 06:27:41 -0400 From: "Dr. David Alan Gilbert (git)" Date: Tue, 16 Jun 2015 11:26:30 +0100 Message-Id: <1434450415-11339-18-git-send-email-dgilbert@redhat.com> In-Reply-To: <1434450415-11339-1-git-send-email-dgilbert@redhat.com> References: <1434450415-11339-1-git-send-email-dgilbert@redhat.com> Subject: [Qemu-devel] [PATCH v7 17/42] Add migration-capability boolean for postcopy-ram. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: aarcange@redhat.com, yamahata@private.email.ne.jp, quintela@redhat.com, liang.z.li@intel.com, luis@cs.umu.se, amit.shah@redhat.com, pbonzini@redhat.com, david@gibson.dropbear.id.au From: "Dr. David Alan Gilbert" The 'postcopy ram' capability allows postcopy migration of RAM; note that the migration starts off in precopy mode until postcopy mode is triggered (see the migrate_start_postcopy patch later in the series). Signed-off-by: Dr. David Alan Gilbert --- include/migration/migration.h | 1 + migration/migration.c | 23 +++++++++++++++++++++++ qapi-schema.json | 6 +++++- 3 files changed, 29 insertions(+), 1 deletion(-) diff --git a/include/migration/migration.h b/include/migration/migration.h index 1bf78f6..da4b72f 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -183,6 +183,7 @@ void migrate_add_blocker(Error *reason); */ void migrate_del_blocker(Error *reason); +bool migrate_postcopy_ram(void); bool migrate_zero_blocks(void); bool migrate_auto_converge(void); diff --git a/migration/migration.c b/migration/migration.c index a743018..cd89a9b 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -408,6 +408,20 @@ void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params, for (cap = params; cap; cap = cap->next) { s->enabled_capabilities[cap->value->capability] = cap->value->state; } + + if (migrate_postcopy_ram()) { + if (migrate_use_compression()) { + /* The decompression threads asynchronously write into RAM + * rather than use the atomic copies needed to avoid + * userfaulting. It should be possible to fix the decompression + * threads for compatibility in future. + */ + error_report("Postcopy is not currently compatible with " + "compression"); + s->enabled_capabilities[MIGRATION_CAPABILITY_X_POSTCOPY_RAM] = + false; + } + } } void qmp_migrate_set_parameters(bool has_compress_level, @@ -770,6 +784,15 @@ void qmp_migrate_set_downtime(double value, Error **errp) max_downtime = (uint64_t)value; } +bool migrate_postcopy_ram(void) +{ + MigrationState *s; + + s = migrate_get_current(); + + return s->enabled_capabilities[MIGRATION_CAPABILITY_X_POSTCOPY_RAM]; +} + bool migrate_auto_converge(void) { MigrationState *s; diff --git a/qapi-schema.json b/qapi-schema.json index 6e17a5c..0b6fe54 100644 --- a/qapi-schema.json +++ b/qapi-schema.json @@ -526,11 +526,15 @@ # @auto-converge: If enabled, QEMU will automatically throttle down the guest # to speed up convergence of RAM migration. (since 1.6) # +# @x-postcopy-ram: Start executing on the migration target before all of RAM has +# been migrated, pulling the remaining pages along as needed. NOTE: If +# the migration fails during postcopy the VM will fail. (since 2.4) +# # Since: 1.2 ## { 'enum': 'MigrationCapability', 'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks', - 'compress'] } + 'compress', 'x-postcopy-ram'] } ## # @MigrationCapabilityStatus -- 2.4.3