| Message ID | 20230714124823.25142-1-wei.w.wang@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v1] migration: refactor migration_completion | expand |
On Fri, Jul 14, 2023 at 08:48:23PM +0800, Wei Wang <wei.w.wang@intel.com> wrote: > Current migration_completion function is a bit long. Refactor the long > implementation into different subfunctions: > - migration_completion_precopy: completion code related to precopy > - migration_completion_postcopy: completion code related to postcopy > - close_return_path_on_source: rp thread related cleanup on migration > completion. It is named to match with open_return_path_on_source. > > This improves readability and is easier for future updates (e.g. add new > subfunctions when completion code related to new features are needed). No > functional changes intended. > > Signed-off-by: Wei Wang <wei.w.wang@intel.com> > --- > migration/migration.c | 181 +++++++++++++++++++++++++----------------- > 1 file changed, 106 insertions(+), 75 deletions(-) > > diff --git a/migration/migration.c b/migration/migration.c > index 91bba630a8..83f1c74f99 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -2058,6 +2058,21 @@ static int await_return_path_close_on_source(MigrationState *ms) > return ms->rp_state.error; > } > > +static int close_return_path_on_source(MigrationState *ms) > +{ > + int ret; > + > + if (!ms->rp_state.rp_thread_created) { > + return 0; > + } > + > + trace_migration_return_path_end_before(); > + ret = await_return_path_close_on_source(ms); > + trace_migration_return_path_end_after(ret); > + > + return ret; > +} > + There is only one caller, migration_completion(). We can consolidate two functions, await_return_path_close_on_source() and close_return_path_on_source(), into single function. > static inline void > migration_wait_main_channel(MigrationState *ms) > { > @@ -2288,66 +2303,107 @@ static int migration_maybe_pause(MigrationState *s, > return s->state == new_state ? 0 : -EINVAL; > } > > -/** > - * migration_completion: Used by migration_thread when there's not much left. > - * The caller 'breaks' the loop when this returns. > - * > - * @s: Current migration state > - */ > -static void migration_completion(MigrationState *s) > +static int migration_completion_precopy(MigrationState *s, > + int *current_active_state) > { > int ret; > - int current_active_state = s->state; > > - if (s->state == MIGRATION_STATUS_ACTIVE) { > - qemu_mutex_lock_iothread(); > - s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); > - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL); > + qemu_mutex_lock_iothread(); > + s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); > + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL); > > - s->vm_old_state = runstate_get(); > - global_state_store(); > + s->vm_old_state = runstate_get(); > + global_state_store(); > > - ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); > - trace_migration_completion_vm_stop(ret); > - if (ret >= 0) { > - ret = migration_maybe_pause(s, ¤t_active_state, > - MIGRATION_STATUS_DEVICE); > - } > - if (ret >= 0) { > - /* > - * Inactivate disks except in COLO, and track that we > - * have done so in order to remember to reactivate > - * them if migration fails or is cancelled. > - */ > - s->block_inactive = !migrate_colo(); > - migration_rate_set(RATE_LIMIT_DISABLED); > - ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false, > - s->block_inactive); > - } > + ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); > + trace_migration_completion_vm_stop(ret); > + if (ret < 0) { > + goto out_unlock; > + } > > - qemu_mutex_unlock_iothread(); > + ret = migration_maybe_pause(s, current_active_state, > + MIGRATION_STATUS_DEVICE); > + if (ret < 0) { > + goto out_unlock; > + } > > - if (ret < 0) { > - goto fail; > - } > - } else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { > - trace_migration_completion_postcopy_end(); > + /* > + * Inactivate disks except in COLO, and track that we have done so in order > + * to remember to reactivate them if migration fails or is cancelled. > + */ > + s->block_inactive = !migrate_colo(); > + migration_rate_set(RATE_LIMIT_DISABLED); > + ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false, > + s->block_inactive); > +out_unlock: > + qemu_mutex_unlock_iothread(); > + return ret; > +} > > - qemu_mutex_lock_iothread(); > - qemu_savevm_state_complete_postcopy(s->to_dst_file); > - qemu_mutex_unlock_iothread(); > +static int migration_completion_postcopy(MigrationState *s) > +{ > + trace_migration_completion_postcopy_end(); > + > + qemu_mutex_lock_iothread(); > + qemu_savevm_state_complete_postcopy(s->to_dst_file); > + qemu_mutex_unlock_iothread(); > + > + /* > + * Shutdown the postcopy fast path thread. This is only needed when dest > + * QEMU binary is old (7.1/7.2). QEMU 8.0+ doesn't need this. > + */ > + if (migrate_postcopy_preempt() && s->preempt_pre_7_2) { > + postcopy_preempt_shutdown_file(s); > + } > + > + trace_migration_completion_postcopy_end_after_complete(); > + > + return 0; Always return 0? Make it void. > +} > > +static void migration_completion_failed(MigrationState *s, > + int current_active_state) > +{ > + if (s->block_inactive && (s->state == MIGRATION_STATUS_ACTIVE || > + s->state == MIGRATION_STATUS_DEVICE)) { > /* > - * Shutdown the postcopy fast path thread. This is only needed > - * when dest QEMU binary is old (7.1/7.2). QEMU 8.0+ doesn't need > - * this. > + * If not doing postcopy, vm_start() will be called: let's > + * regain control on images. > */ > - if (migrate_postcopy_preempt() && s->preempt_pre_7_2) { > - postcopy_preempt_shutdown_file(s); > + Error *local_err = NULL; > + > + qemu_mutex_lock_iothread(); > + bdrv_activate_all(&local_err); > + if (local_err) { > + error_report_err(local_err); > + } else { > + s->block_inactive = false; > } > + qemu_mutex_unlock_iothread(); > + } > > - trace_migration_completion_postcopy_end_after_complete(); > - } else { > + migrate_set_state(&s->state, current_active_state, > + MIGRATION_STATUS_FAILED); > +} > + > +/** > + * migration_completion: Used by migration_thread when there's not much left. > + * The caller 'breaks' the loop when this returns. > + * > + * @s: Current migration state > + */ > +static void migration_completion(MigrationState *s) > +{ > + int ret = -1; > + int current_active_state = s->state; > + > + if (s->state == MIGRATION_STATUS_ACTIVE) { > + ret = migration_completion_precopy(s, ¤t_active_state); > + } else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { > + ret = migration_completion_postcopy(s); Here we can set ret = 0. > + } > + > + if (ret < 0) { > goto fail; > } > > @@ -2357,14 +2413,8 @@ static void migration_completion(MigrationState *s) > * it will wait for the destination to send it's status in > * a SHUT command). > */ > - if (s->rp_state.rp_thread_created) { > - int rp_error; > - trace_migration_return_path_end_before(); > - rp_error = await_return_path_close_on_source(s); > - trace_migration_return_path_end_after(rp_error); > - if (rp_error) { > - goto fail; > - } > + if (close_return_path_on_source(s) < 0) { > + goto fail; > } > > if (qemu_file_get_error(s->to_dst_file)) { > @@ -2384,26 +2434,7 @@ static void migration_completion(MigrationState *s) > return; > > fail: > - if (s->block_inactive && (s->state == MIGRATION_STATUS_ACTIVE || > - s->state == MIGRATION_STATUS_DEVICE)) { > - /* > - * If not doing postcopy, vm_start() will be called: let's > - * regain control on images. > - */ > - Error *local_err = NULL; > - > - qemu_mutex_lock_iothread(); > - bdrv_activate_all(&local_err); > - if (local_err) { > - error_report_err(local_err); > - } else { > - s->block_inactive = false; > - } > - qemu_mutex_unlock_iothread(); > - } > - > - migrate_set_state(&s->state, current_active_state, > - MIGRATION_STATUS_FAILED); > + migration_completion_failed(s, current_active_state); > } > > /** > -- > 2.27.0 > >
On Tuesday, July 18, 2023 1:44 PM, Isaku Yamahata wrote: > > --- a/migration/migration.c > > +++ b/migration/migration.c > > @@ -2058,6 +2058,21 @@ static int > await_return_path_close_on_source(MigrationState *ms) > > return ms->rp_state.error; > > } > > > > +static int close_return_path_on_source(MigrationState *ms) { > > + int ret; > > + > > + if (!ms->rp_state.rp_thread_created) { > > + return 0; > > + } > > + > > + trace_migration_return_path_end_before(); > > + ret = await_return_path_close_on_source(ms); > > + trace_migration_return_path_end_after(ret); > > + > > + return ret; > > +} > > + > > There is only one caller, migration_completion(). We can consolidate two > functions, await_return_path_close_on_source() and > close_return_path_on_source(), into single function. Sounds good, thanks. > > +static int migration_completion_postcopy(MigrationState *s) { > > + trace_migration_completion_postcopy_end(); > > + > > + qemu_mutex_lock_iothread(); > > + qemu_savevm_state_complete_postcopy(s->to_dst_file); > > + qemu_mutex_unlock_iothread(); > > + > > + /* > > + * Shutdown the postcopy fast path thread. This is only needed when > dest > > + * QEMU binary is old (7.1/7.2). QEMU 8.0+ doesn't need this. > > + */ > > + if (migrate_postcopy_preempt() && s->preempt_pre_7_2) { > > + postcopy_preempt_shutdown_file(s); > > + } > > + > > + trace_migration_completion_postcopy_end_after_complete(); > > + > > + return 0; > > Always return 0? Make it void. OK. > > +static void migration_completion(MigrationState *s) { > > + int ret = -1; > > + int current_active_state = s->state; > > + > > + if (s->state == MIGRATION_STATUS_ACTIVE) { > > + ret = migration_completion_precopy(s, ¤t_active_state); > > + } else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { > > + ret = migration_completion_postcopy(s); > > Here we can set ret = 0. Yes, after migration_completion_postcopy is made "void".
On Tue, Jul 18, 2023 at 01:25:12PM +0000, Wang, Wei W wrote: > On Tuesday, July 18, 2023 1:44 PM, Isaku Yamahata wrote: > > > --- a/migration/migration.c > > > +++ b/migration/migration.c > > > @@ -2058,6 +2058,21 @@ static int > > await_return_path_close_on_source(MigrationState *ms) > > > return ms->rp_state.error; > > > } > > > > > > +static int close_return_path_on_source(MigrationState *ms) { > > > + int ret; > > > + > > > + if (!ms->rp_state.rp_thread_created) { > > > + return 0; > > > + } > > > + > > > + trace_migration_return_path_end_before(); > > > + ret = await_return_path_close_on_source(ms); > > > + trace_migration_return_path_end_after(ret); > > > + > > > + return ret; > > > +} > > > + > > > > There is only one caller, migration_completion(). We can consolidate two > > functions, await_return_path_close_on_source() and > > close_return_path_on_source(), into single function. > > Sounds good, thanks. > > > > +static int migration_completion_postcopy(MigrationState *s) { > > > + trace_migration_completion_postcopy_end(); > > > + > > > + qemu_mutex_lock_iothread(); > > > + qemu_savevm_state_complete_postcopy(s->to_dst_file); > > > + qemu_mutex_unlock_iothread(); > > > + > > > + /* > > > + * Shutdown the postcopy fast path thread. This is only needed when > > dest > > > + * QEMU binary is old (7.1/7.2). QEMU 8.0+ doesn't need this. > > > + */ > > > + if (migrate_postcopy_preempt() && s->preempt_pre_7_2) { > > > + postcopy_preempt_shutdown_file(s); > > > + } > > > + > > > + trace_migration_completion_postcopy_end_after_complete(); > > > + > > > + return 0; > > > > Always return 0? Make it void. > > OK. > > > > +static void migration_completion(MigrationState *s) { > > > + int ret = -1; > > > + int current_active_state = s->state; > > > + > > > + if (s->state == MIGRATION_STATUS_ACTIVE) { > > > + ret = migration_completion_precopy(s, ¤t_active_state); > > > + } else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { > > > + ret = migration_completion_postcopy(s); > > > > Here we can set ret = 0. > > Yes, after migration_completion_postcopy is made "void". Looks good to me, after addressing Isaku's comments. The current_active_state is very unfortunate, along with most of the calls to migrate_set_state() - I bet most of the code will definitely go wrong if that cmpxchg didn't succeed inside of migrate_set_state(), IOW in most cases we simply always want: migrate_set_state(&s->state, s->state, XXX); Not sure whether one pre-requisite patch is good to have so we can rename migrate_set_state() to something like __migrate_set_state(), then: migrate_set_state(s, XXX) { __migrate_set_state(&s->state, s->state, XXX); } I don't even know whether there's any call site that will need __migrate_set_state() for real.. Thanks,
On Friday, July 21, 2023 4:38 AM, Peter Xu wrote: > Looks good to me, after addressing Isaku's comments. > > The current_active_state is very unfortunate, along with most of the calls to > migrate_set_state() - I bet most of the code will definitely go wrong if that > cmpxchg didn't succeed inside of migrate_set_state(), IOW in most cases we > simply always want: Can you share examples where it could be wrong? (If it has bugs, we need to fix) > > migrate_set_state(&s->state, s->state, XXX); > > Not sure whether one pre-requisite patch is good to have so we can rename > migrate_set_state() to something like __migrate_set_state(), then: > > migrate_set_state(s, XXX) { > __migrate_set_state(&s->state, s->state, XXX); > } > > I don't even know whether there's any call site that will need > __migrate_set_state() for real.. > Seems this would break the use of "MIGRATION_STATUS_CANCELLING". For example, - In migration_maybe_pause: migrate_set_state(&s->state, MIGRATION_STATUS_PRE_SWITCHOVER, new_state); If the current s->state isn't MIGRATION_STATUS_PRE_SWITCHOVER (could be MIGRATION_STATUS_CANCELLING), then s->state won’t be updated to new_state. - Then, in migration_completion, the following update to s->state won't succeed: migrate_set_state(&s->state, current_active_state, MIGRATION_STATUS_COMPLETED); - Finally, when reaching migration_iteration_finish(), s->state is MIGRATION_STATUS_CANCELLING, instead of MIGRATION_STATUS_COMPLETED.
On Fri, Jul 21, 2023 at 11:14:55AM +0000, Wang, Wei W wrote: > On Friday, July 21, 2023 4:38 AM, Peter Xu wrote: > > Looks good to me, after addressing Isaku's comments. > > > > The current_active_state is very unfortunate, along with most of the calls to > > migrate_set_state() - I bet most of the code will definitely go wrong if that > > cmpxchg didn't succeed inside of migrate_set_state(), IOW in most cases we > > simply always want: > > Can you share examples where it could be wrong? > (If it has bugs, we need to fix) Nop. What I meant is most of the cases we want to set the state without caring much about the old state, so at least we can have a helper like below and simply call migrate_set_state(s, STATE) where we don't care old state. > > > > > migrate_set_state(&s->state, s->state, XXX); > > > > Not sure whether one pre-requisite patch is good to have so we can rename > > migrate_set_state() to something like __migrate_set_state(), then: > > > > migrate_set_state(s, XXX) { > > __migrate_set_state(&s->state, s->state, XXX); > > } > > > > I don't even know whether there's any call site that will need > > __migrate_set_state() for real.. > > > > Seems this would break the use of "MIGRATION_STATUS_CANCELLING". > For example, > - In migration_maybe_pause: > migrate_set_state(&s->state, MIGRATION_STATUS_PRE_SWITCHOVER, > new_state); > If the current s->state isn't MIGRATION_STATUS_PRE_SWITCHOVER (could > be MIGRATION_STATUS_CANCELLING), then s->state won’t be updated to > new_state. > - Then, in migration_completion, the following update to s->state won't succeed: > migrate_set_state(&s->state, current_active_state, > MIGRATION_STATUS_COMPLETED); > > - Finally, when reaching migration_iteration_finish(), s->state is > MIGRATION_STATUS_CANCELLING, instead of MIGRATION_STATUS_COMPLETED. The whole state changes are just flaky to me in general, even with the help of old_state cmpxchg. E.g., I'm wondering whether below race can happen, assuming we're starting with ACTIVE state and just about to complete migration: main thread migration thread ----------- ---------------- migration_maybe_pause(current_active_state==ACTIVE) if (s->state != MIGRATION_STATUS_CANCELLING) --> true, keep setting state qemu_mutex_unlock_iothread(); qemu_mutex_lock_iothread(); migrate_fd_cancel() if (old_state == MIGRATION_STATUS_PRE_SWITCHOVER) --> false, not posting to pause_sem set state to MIGRATION_STATUS_CANCELLING migrate_set_state(&s->state, *current_active_state, MIGRATION_STATUS_PRE_SWITCHOVER); --> false, cmpxchg fail qemu_sem_wait(&s->pause_sem); --> hang death? Thanks,
On Thursday, July 27, 2023 1:10 AM, Peter Xu wrote: > On Fri, Jul 21, 2023 at 11:14:55AM +0000, Wang, Wei W wrote: > > On Friday, July 21, 2023 4:38 AM, Peter Xu wrote: > > > Looks good to me, after addressing Isaku's comments. > > > > > > The current_active_state is very unfortunate, along with most of the > > > calls to > > > migrate_set_state() - I bet most of the code will definitely go > > > wrong if that cmpxchg didn't succeed inside of migrate_set_state(), > > > IOW in most cases we simply always want: > > > > Can you share examples where it could be wrong? > > (If it has bugs, we need to fix) > > Nop. What I meant is most of the cases we want to set the state without > caring much about the old state, so at least we can have a helper like below > and simply call migrate_set_state(s, STATE) where we don't care old state. > > > > > > > > > migrate_set_state(&s->state, s->state, XXX); > > > > > > Not sure whether one pre-requisite patch is good to have so we can > > > rename > > > migrate_set_state() to something like __migrate_set_state(), then: > > > > > > migrate_set_state(s, XXX) { > > > __migrate_set_state(&s->state, s->state, XXX); > > > } > > > > > > I don't even know whether there's any call site that will need > > > __migrate_set_state() for real.. > > > > > > > Seems this would break the use of "MIGRATION_STATUS_CANCELLING". > > For example, > > - In migration_maybe_pause: > > migrate_set_state(&s->state, MIGRATION_STATUS_PRE_SWITCHOVER, > > new_state); If the current > > s->state isn't MIGRATION_STATUS_PRE_SWITCHOVER (could be > > MIGRATION_STATUS_CANCELLING), then s->state won’t be updated to > > new_state. > > - Then, in migration_completion, the following update to s->state won't > succeed: > > migrate_set_state(&s->state, current_active_state, > > MIGRATION_STATUS_COMPLETED); > > > > - Finally, when reaching migration_iteration_finish(), s->state is > > MIGRATION_STATUS_CANCELLING, instead of > MIGRATION_STATUS_COMPLETED. > > The whole state changes are just flaky to me in general, even with the help of > old_state cmpxchg. Yes, the design/implementation of the migration state transition can be improved (it looks fragile to me). I think this should be done in a separate patchset, though. For this patch, we could keep it no functional change. > > E.g., I'm wondering whether below race can happen, assuming we're starting > with ACTIVE state and just about to complete migration: > > main thread migration thread > ----------- ---------------- > > migration_maybe_pause(current_active_state==ACTIVE) > if (s->state != MIGRATION_STATUS_CANCELLING) > --> true, keep setting state > qemu_mutex_unlock_iothread(); > qemu_mutex_lock_iothread(); > migrate_fd_cancel() > if (old_state == MIGRATION_STATUS_PRE_SWITCHOVER) > --> false, not posting to pause_sem > set state to MIGRATION_STATUS_CANCELLING > migrate_set_state(&s->state, *current_active_state, > MIGRATION_STATUS_PRE_SWITCHOVER); > --> false, cmpxchg fail > qemu_sem_wait(&s->pause_sem); > --> hang death? Still need "migrate continue" to unblock the migration thread. Probably we should document that PAUSE_BEFORE_SWITCHOVER always requires an explicit "migrate continue" to be issued from user (even after migration is cancelled).
diff --git a/migration/migration.c b/migration/migration.c index 91bba630a8..83f1c74f99 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -2058,6 +2058,21 @@ static int await_return_path_close_on_source(MigrationState *ms) return ms->rp_state.error; } +static int close_return_path_on_source(MigrationState *ms) +{ + int ret; + + if (!ms->rp_state.rp_thread_created) { + return 0; + } + + trace_migration_return_path_end_before(); + ret = await_return_path_close_on_source(ms); + trace_migration_return_path_end_after(ret); + + return ret; +} + static inline void migration_wait_main_channel(MigrationState *ms) { @@ -2288,66 +2303,107 @@ static int migration_maybe_pause(MigrationState *s, return s->state == new_state ? 0 : -EINVAL; } -/** - * migration_completion: Used by migration_thread when there's not much left. - * The caller 'breaks' the loop when this returns. - * - * @s: Current migration state - */ -static void migration_completion(MigrationState *s) +static int migration_completion_precopy(MigrationState *s, + int *current_active_state) { int ret; - int current_active_state = s->state; - if (s->state == MIGRATION_STATUS_ACTIVE) { - qemu_mutex_lock_iothread(); - s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL); + qemu_mutex_lock_iothread(); + s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL); - s->vm_old_state = runstate_get(); - global_state_store(); + s->vm_old_state = runstate_get(); + global_state_store(); - ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); - trace_migration_completion_vm_stop(ret); - if (ret >= 0) { - ret = migration_maybe_pause(s, ¤t_active_state, - MIGRATION_STATUS_DEVICE); - } - if (ret >= 0) { - /* - * Inactivate disks except in COLO, and track that we - * have done so in order to remember to reactivate - * them if migration fails or is cancelled. - */ - s->block_inactive = !migrate_colo(); - migration_rate_set(RATE_LIMIT_DISABLED); - ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false, - s->block_inactive); - } + ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); + trace_migration_completion_vm_stop(ret); + if (ret < 0) { + goto out_unlock; + } - qemu_mutex_unlock_iothread(); + ret = migration_maybe_pause(s, current_active_state, + MIGRATION_STATUS_DEVICE); + if (ret < 0) { + goto out_unlock; + } - if (ret < 0) { - goto fail; - } - } else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { - trace_migration_completion_postcopy_end(); + /* + * Inactivate disks except in COLO, and track that we have done so in order + * to remember to reactivate them if migration fails or is cancelled. + */ + s->block_inactive = !migrate_colo(); + migration_rate_set(RATE_LIMIT_DISABLED); + ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false, + s->block_inactive); +out_unlock: + qemu_mutex_unlock_iothread(); + return ret; +} - qemu_mutex_lock_iothread(); - qemu_savevm_state_complete_postcopy(s->to_dst_file); - qemu_mutex_unlock_iothread(); +static int migration_completion_postcopy(MigrationState *s) +{ + trace_migration_completion_postcopy_end(); + + qemu_mutex_lock_iothread(); + qemu_savevm_state_complete_postcopy(s->to_dst_file); + qemu_mutex_unlock_iothread(); + + /* + * Shutdown the postcopy fast path thread. This is only needed when dest + * QEMU binary is old (7.1/7.2). QEMU 8.0+ doesn't need this. + */ + if (migrate_postcopy_preempt() && s->preempt_pre_7_2) { + postcopy_preempt_shutdown_file(s); + } + + trace_migration_completion_postcopy_end_after_complete(); + + return 0; +} +static void migration_completion_failed(MigrationState *s, + int current_active_state) +{ + if (s->block_inactive && (s->state == MIGRATION_STATUS_ACTIVE || + s->state == MIGRATION_STATUS_DEVICE)) { /* - * Shutdown the postcopy fast path thread. This is only needed - * when dest QEMU binary is old (7.1/7.2). QEMU 8.0+ doesn't need - * this. + * If not doing postcopy, vm_start() will be called: let's + * regain control on images. */ - if (migrate_postcopy_preempt() && s->preempt_pre_7_2) { - postcopy_preempt_shutdown_file(s); + Error *local_err = NULL; + + qemu_mutex_lock_iothread(); + bdrv_activate_all(&local_err); + if (local_err) { + error_report_err(local_err); + } else { + s->block_inactive = false; } + qemu_mutex_unlock_iothread(); + } - trace_migration_completion_postcopy_end_after_complete(); - } else { + migrate_set_state(&s->state, current_active_state, + MIGRATION_STATUS_FAILED); +} + +/** + * migration_completion: Used by migration_thread when there's not much left. + * The caller 'breaks' the loop when this returns. + * + * @s: Current migration state + */ +static void migration_completion(MigrationState *s) +{ + int ret = -1; + int current_active_state = s->state; + + if (s->state == MIGRATION_STATUS_ACTIVE) { + ret = migration_completion_precopy(s, ¤t_active_state); + } else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { + ret = migration_completion_postcopy(s); + } + + if (ret < 0) { goto fail; } @@ -2357,14 +2413,8 @@ static void migration_completion(MigrationState *s) * it will wait for the destination to send it's status in * a SHUT command). */ - if (s->rp_state.rp_thread_created) { - int rp_error; - trace_migration_return_path_end_before(); - rp_error = await_return_path_close_on_source(s); - trace_migration_return_path_end_after(rp_error); - if (rp_error) { - goto fail; - } + if (close_return_path_on_source(s) < 0) { + goto fail; } if (qemu_file_get_error(s->to_dst_file)) { @@ -2384,26 +2434,7 @@ static void migration_completion(MigrationState *s) return; fail: - if (s->block_inactive && (s->state == MIGRATION_STATUS_ACTIVE || - s->state == MIGRATION_STATUS_DEVICE)) { - /* - * If not doing postcopy, vm_start() will be called: let's - * regain control on images. - */ - Error *local_err = NULL; - - qemu_mutex_lock_iothread(); - bdrv_activate_all(&local_err); - if (local_err) { - error_report_err(local_err); - } else { - s->block_inactive = false; - } - qemu_mutex_unlock_iothread(); - } - - migrate_set_state(&s->state, current_active_state, - MIGRATION_STATUS_FAILED); + migration_completion_failed(s, current_active_state); } /**
Current migration_completion function is a bit long. Refactor the long implementation into different subfunctions: - migration_completion_precopy: completion code related to precopy - migration_completion_postcopy: completion code related to postcopy - close_return_path_on_source: rp thread related cleanup on migration completion. It is named to match with open_return_path_on_source. This improves readability and is easier for future updates (e.g. add new subfunctions when completion code related to new features are needed). No functional changes intended. Signed-off-by: Wei Wang <wei.w.wang@intel.com> --- migration/migration.c | 181 +++++++++++++++++++++++++----------------- 1 file changed, 106 insertions(+), 75 deletions(-)