From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41760) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dY2UK-0006eK-D8 for qemu-devel@nongnu.org; Wed, 19 Jul 2017 23:50:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dY2UH-0003Y3-Aj for qemu-devel@nongnu.org; Wed, 19 Jul 2017 23:50:56 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:4471) by eggs.gnu.org with esmtps (TLS1.0:RSA_ARCFOUR_SHA1:16) (Exim 4.71) (envelope-from ) id 1dY2UG-0003Uq-N7 for qemu-devel@nongnu.org; Wed, 19 Jul 2017 23:50:53 -0400 From: Jay Zhou Date: Thu, 20 Jul 2017 11:49:29 +0800 Message-ID: <1500522569-10760-1-git-send-email-jianjay.zhou@huawei.com> MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH] migration: optimize the downtime List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: quintela@redhat.com, dgilbert@redhat.com, armbru@redhat.com, arei.gonglei@huawei.com, zhang.zhanghailiang@huawei.com, wangxinxin.wang@huawei.com, weidong.huang@huawei.com, Jay Zhou Qemu_savevm_state_cleanup() takes about 300ms in my ram migration tests with a 8U24G vm(20G is really occupied), the main cost comes from KVM_SET_USER_MEMORY_REGION ioctl when mem.memory_size = 0 in kvm_set_user_memory_region(). In kmod, the main cost is kvm_zap_obsolete_pages(), which traverses the active_mmu_pages list to zap the unsync sptes. I think it can be optimized: (1) source vm will be destroyed if the migration is successfully done, so the resources will be cleanuped automatically by the system (2) delay the cleanup if the migration failed Signed-off-by: Jay Zhou --- migration/migration.c | 16 +++++++++------- qmp.c | 10 ++++++++++ 2 files changed, 19 insertions(+), 7 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index a0db40d..72832be 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1877,6 +1877,15 @@ static void *migration_thread(void *opaque) if (qemu_file_get_error(s->to_dst_file)) { migrate_set_state(&s->state, current_active_state, MIGRATION_STATUS_FAILED); + /* + * The resource has been allocated by migration will be reused in + * COLO process, so don't release them. + */ + if (!enable_colo) { + qemu_mutex_lock_iothread(); + qemu_savevm_state_cleanup(); + qemu_mutex_unlock_iothread(); + } trace_migration_thread_file_err(); break; } @@ -1916,13 +1925,6 @@ static void *migration_thread(void *opaque) end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); qemu_mutex_lock_iothread(); - /* - * The resource has been allocated by migration will be reused in COLO - * process, so don't release them. - */ - if (!enable_colo) { - qemu_savevm_state_cleanup(); - } if (s->state == MIGRATION_STATUS_COMPLETED) { uint64_t transferred_bytes = qemu_ftell(s->to_dst_file); s->total_time = end_time - s->total_time; diff --git a/qmp.c b/qmp.c index b86201e..0e68eaa 100644 --- a/qmp.c +++ b/qmp.c @@ -37,6 +37,8 @@ #include "qom/object_interfaces.h" #include "hw/mem/pc-dimm.h" #include "hw/acpi/acpi_dev_interface.h" +#include "migration/migration.h" +#include "migration/savevm.h" NameInfo *qmp_query_name(Error **errp) { @@ -200,6 +202,14 @@ void qmp_cont(Error **errp) if (runstate_check(RUN_STATE_INMIGRATE)) { autostart = 1; } else { + /* + * Delay the cleanup to reduce the downtime of migration. + * The resource has been allocated by migration will be reused + * in COLO process, so don't release them. + */ + if (runstate_check(RUN_STATE_POSTMIGRATE) && !migrate_colo_enabled()) { + qemu_savevm_state_cleanup(); + } vm_start(); } } -- 1.8.3.1