| Message ID | 20180103054043.25719-3-peterx@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Peter Xu <peterx@redhat.com> wrote: > Moving existing callers all into migrate_fd_cleanup(). It simplifies > migration_thread() a bit. > > Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> I am trying to see if we can call migrate_fd_cleanup() twice. As far as I can see, we are not doing it. But, and it is a big but, we are not checking that we are not calling qemu_savevm_state_cleanup() twice. If that happens, we can get double frees and similar. I put the reviewed-by anyways, because I *think* that we are doing it right now, and otherwise, we should make sure that we are not calling it twice, not papering over it. Once here, I have notice that we call block_cleanup_parameters() in *three* places. We call notifier_list_notify() on two of this places (I can't see any good reason *why* we don't call the notifier for migrate_fd_cancel). So, still more review/cleanups to do on this arera. Later, Juan. > --- > migration/migration.c | 10 ++-------- > 1 file changed, 2 insertions(+), 8 deletions(-) > > diff --git a/migration/migration.c b/migration/migration.c > index 0ee4b4c27c..edbda43246 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -1077,6 +1077,8 @@ static void migrate_fd_cleanup(void *opaque) > qemu_bh_delete(s->cleanup_bh); > s->cleanup_bh = NULL; > > + qemu_savevm_state_cleanup(); > + > if (s->to_dst_file) { > Error *local_err = NULL; > > @@ -2290,13 +2292,6 @@ 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; > @@ -2312,7 +2307,6 @@ static void *migration_thread(void *opaque) > if (s->state == MIGRATION_STATUS_ACTIVE) { > assert(enable_colo); > migrate_start_colo_process(s); > - qemu_savevm_state_cleanup(); > /* > * Fixme: we will run VM in COLO no matter its old running state. > * After exited COLO, we will keep running.
On Wed, Jan 03, 2018 at 10:15:41AM +0100, Juan Quintela wrote: > Peter Xu <peterx@redhat.com> wrote: > > Moving existing callers all into migrate_fd_cleanup(). It simplifies > > migration_thread() a bit. > > > > Signed-off-by: Peter Xu <peterx@redhat.com> > > Reviewed-by: Juan Quintela <quintela@redhat.com> Thanks. > > I am trying to see if we can call migrate_fd_cleanup() twice. As far as > I can see, we are not doing it. But, and it is a big but, we are not > checking that we are not calling qemu_savevm_state_cleanup() twice. If > that happens, we can get double frees and similar. > > I put the reviewed-by anyways, because I *think* that we are doing it > right now, and otherwise, we should make sure that we are not calling it > twice, not papering over it. > > Once here, I have notice that we call block_cleanup_parameters() in > *three* places. We call notifier_list_notify() on two of this places (I > can't see any good reason *why* we don't call the notifier for > migrate_fd_cancel). Indeed. IMHO we can remove two calls of block_cleanup_parameters(), only keep the one in migrate_fd_cleanup(), and remove on notifier_list_notify() in migrate_fd_error() (these can be two more patches). What do you think?
Peter Xu <peterx@redhat.com> wrote: > On Wed, Jan 03, 2018 at 10:15:41AM +0100, Juan Quintela wrote: >> Peter Xu <peterx@redhat.com> wrote: >> > Moving existing callers all into migrate_fd_cleanup(). It simplifies >> > migration_thread() a bit. >> > >> > Signed-off-by: Peter Xu <peterx@redhat.com> >> >> Reviewed-by: Juan Quintela <quintela@redhat.com> > > Thanks. > >> >> I am trying to see if we can call migrate_fd_cleanup() twice. As far as >> I can see, we are not doing it. But, and it is a big but, we are not >> checking that we are not calling qemu_savevm_state_cleanup() twice. If >> that happens, we can get double frees and similar. >> >> I put the reviewed-by anyways, because I *think* that we are doing it >> right now, and otherwise, we should make sure that we are not calling it >> twice, not papering over it. >> >> Once here, I have notice that we call block_cleanup_parameters() in >> *three* places. We call notifier_list_notify() on two of this places (I >> can't see any good reason *why* we don't call the notifier for >> migrate_fd_cancel). > > Indeed. > > IMHO we can remove two calls of block_cleanup_parameters(), only keep > the one in migrate_fd_cleanup(), and remove on notifier_list_notify() > in migrate_fd_error() (these can be two more patches). What do you > think? I think we need to make sure that we have a function that we always call at the end. I think that we have that on migration_fd_cleanup(), so put everything there should be ok, no? Later, Juan.
On Wed, Jan 03, 2018 at 11:21:31AM +0100, Juan Quintela wrote: > Peter Xu <peterx@redhat.com> wrote: > > On Wed, Jan 03, 2018 at 10:15:41AM +0100, Juan Quintela wrote: > >> Peter Xu <peterx@redhat.com> wrote: > >> > Moving existing callers all into migrate_fd_cleanup(). It simplifies > >> > migration_thread() a bit. > >> > > >> > Signed-off-by: Peter Xu <peterx@redhat.com> > >> > >> Reviewed-by: Juan Quintela <quintela@redhat.com> > > > > Thanks. > > > >> > >> I am trying to see if we can call migrate_fd_cleanup() twice. As far as > >> I can see, we are not doing it. But, and it is a big but, we are not > >> checking that we are not calling qemu_savevm_state_cleanup() twice. If > >> that happens, we can get double frees and similar. > >> > >> I put the reviewed-by anyways, because I *think* that we are doing it > >> right now, and otherwise, we should make sure that we are not calling it > >> twice, not papering over it. > >> > >> Once here, I have notice that we call block_cleanup_parameters() in > >> *three* places. We call notifier_list_notify() on two of this places (I > >> can't see any good reason *why* we don't call the notifier for > >> migrate_fd_cancel). > > > > Indeed. > > > > IMHO we can remove two calls of block_cleanup_parameters(), only keep > > the one in migrate_fd_cleanup(), and remove on notifier_list_notify() > > in migrate_fd_error() (these can be two more patches). What do you > > think? > > I think we need to make sure that we have a function that we always > call at the end. I think that we have that on migration_fd_cleanup(), > so put everything there should be ok, no? IMHO that's exactly what I mean, no? :) For notifier_list_notify(), it's different - I just remove the extra one in migrate_fd_error() because it'll be called in migrate_fd_cleanup() as well, which is a duplicate.
Peter Xu <peterx@redhat.com> wrote: > On Wed, Jan 03, 2018 at 11:21:31AM +0100, Juan Quintela wrote: >> Peter Xu <peterx@redhat.com> wrote: >> > On Wed, Jan 03, 2018 at 10:15:41AM +0100, Juan Quintela wrote: >> >> Peter Xu <peterx@redhat.com> wrote: >> >> > Moving existing callers all into migrate_fd_cleanup(). It simplifies >> >> > migration_thread() a bit. >> >> > >> >> > Signed-off-by: Peter Xu <peterx@redhat.com> >> >> >> >> Reviewed-by: Juan Quintela <quintela@redhat.com> >> > >> > Thanks. >> > >> >> >> >> I am trying to see if we can call migrate_fd_cleanup() twice. As far as >> >> I can see, we are not doing it. But, and it is a big but, we are not >> >> checking that we are not calling qemu_savevm_state_cleanup() twice. If >> >> that happens, we can get double frees and similar. >> >> >> >> I put the reviewed-by anyways, because I *think* that we are doing it >> >> right now, and otherwise, we should make sure that we are not calling it >> >> twice, not papering over it. >> >> >> >> Once here, I have notice that we call block_cleanup_parameters() in >> >> *three* places. We call notifier_list_notify() on two of this places (I >> >> can't see any good reason *why* we don't call the notifier for >> >> migrate_fd_cancel). >> > >> > Indeed. >> > >> > IMHO we can remove two calls of block_cleanup_parameters(), only keep >> > the one in migrate_fd_cleanup(), and remove on notifier_list_notify() >> > in migrate_fd_error() (these can be two more patches). What do you >> > think? >> >> I think we need to make sure that we have a function that we always >> call at the end. I think that we have that on migration_fd_cleanup(), >> so put everything there should be ok, no? > > IMHO that's exactly what I mean, no? :) > > For notifier_list_notify(), it's different - I just remove the extra > one in migrate_fd_error() because it'll be called in > migrate_fd_cleanup() as well, which is a duplicate. then what call the one when we do a cancel? the one in cleanup also? Thanks, Juan.
On Wed, Jan 03, 2018 at 12:18:54PM +0100, Juan Quintela wrote: > Peter Xu <peterx@redhat.com> wrote: > > On Wed, Jan 03, 2018 at 11:21:31AM +0100, Juan Quintela wrote: > >> Peter Xu <peterx@redhat.com> wrote: > >> > On Wed, Jan 03, 2018 at 10:15:41AM +0100, Juan Quintela wrote: > >> >> Peter Xu <peterx@redhat.com> wrote: > >> >> > Moving existing callers all into migrate_fd_cleanup(). It simplifies > >> >> > migration_thread() a bit. > >> >> > > >> >> > Signed-off-by: Peter Xu <peterx@redhat.com> > >> >> > >> >> Reviewed-by: Juan Quintela <quintela@redhat.com> > >> > > >> > Thanks. > >> > > >> >> > >> >> I am trying to see if we can call migrate_fd_cleanup() twice. As far as > >> >> I can see, we are not doing it. But, and it is a big but, we are not > >> >> checking that we are not calling qemu_savevm_state_cleanup() twice. If > >> >> that happens, we can get double frees and similar. > >> >> > >> >> I put the reviewed-by anyways, because I *think* that we are doing it > >> >> right now, and otherwise, we should make sure that we are not calling it > >> >> twice, not papering over it. > >> >> > >> >> Once here, I have notice that we call block_cleanup_parameters() in > >> >> *three* places. We call notifier_list_notify() on two of this places (I > >> >> can't see any good reason *why* we don't call the notifier for > >> >> migrate_fd_cancel). > >> > > >> > Indeed. > >> > > >> > IMHO we can remove two calls of block_cleanup_parameters(), only keep > >> > the one in migrate_fd_cleanup(), and remove on notifier_list_notify() > >> > in migrate_fd_error() (these can be two more patches). What do you > >> > think? > >> > >> I think we need to make sure that we have a function that we always > >> call at the end. I think that we have that on migration_fd_cleanup(), > >> so put everything there should be ok, no? > > > > IMHO that's exactly what I mean, no? :) > > > > For notifier_list_notify(), it's different - I just remove the extra > > one in migrate_fd_error() because it'll be called in > > migrate_fd_cleanup() as well, which is a duplicate. > > then what call the one when we do a cancel? the one in cleanup also? Yes, IIUC migrate_fd_cancel() tells the thread to cancel, then the migrate_fd_cleanup() is called there (finally in the bottom half of main loop, of course).
diff --git a/migration/migration.c b/migration/migration.c index 0ee4b4c27c..edbda43246 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1077,6 +1077,8 @@ static void migrate_fd_cleanup(void *opaque) qemu_bh_delete(s->cleanup_bh); s->cleanup_bh = NULL; + qemu_savevm_state_cleanup(); + if (s->to_dst_file) { Error *local_err = NULL; @@ -2290,13 +2292,6 @@ 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; @@ -2312,7 +2307,6 @@ static void *migration_thread(void *opaque) if (s->state == MIGRATION_STATUS_ACTIVE) { assert(enable_colo); migrate_start_colo_process(s); - qemu_savevm_state_cleanup(); /* * Fixme: we will run VM in COLO no matter its old running state. * After exited COLO, we will keep running.
Moving existing callers all into migrate_fd_cleanup(). It simplifies migration_thread() a bit. Signed-off-by: Peter Xu <peterx@redhat.com> --- migration/migration.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-)