diff options
author | Peter Xu <peterx@redhat.com> | 2021-07-22 13:58:41 -0400 |
---|---|---|
committer | Dr. David Alan Gilbert <dgilbert@redhat.com> | 2021-07-26 12:45:03 +0100 |
commit | 39675ffffb3394d44b880d083a214c5e44786170 (patch) | |
tree | ac3be89aab3c71d61ad772e6c28f7fe523f43ff7 | |
parent | c6ad5be7ae5b8c6bbbd0c592bbf18d4a78540516 (diff) | |
download | qemu-39675ffffb3394d44b880d083a214c5e44786170.zip qemu-39675ffffb3394d44b880d083a214c5e44786170.tar.gz qemu-39675ffffb3394d44b880d083a214c5e44786170.tar.bz2 |
migration: Move the yank unregister of channel_close out
It's efficient, but hackish to call yank unregister calls in channel_close(),
especially it'll be hard to debug when qemu crashed with some yank function
leaked.
Remove that hack, but instead explicitly unregister yank functions at the
places where needed, they are:
(on src)
- migrate_fd_cleanup
- postcopy_pause
(on dst)
- migration_incoming_state_destroy
- postcopy_pause_incoming
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20210722175841.938739-6-peterx@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
-rw-r--r-- | migration/migration.c | 14 | ||||
-rw-r--r-- | migration/qemu-file-channel.c | 3 | ||||
-rw-r--r-- | migration/savevm.c | 7 | ||||
-rw-r--r-- | migration/yank_functions.c | 14 | ||||
-rw-r--r-- | migration/yank_functions.h | 1 |
5 files changed, 35 insertions, 4 deletions
diff --git a/migration/migration.c b/migration/migration.c index 62dbcb7..041b845 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -59,6 +59,7 @@ #include "multifd.h" #include "qemu/yank.h" #include "sysemu/cpus.h" +#include "yank_functions.h" #define MAX_THROTTLE (128 << 20) /* Migration transfer speed throttling */ @@ -273,6 +274,7 @@ void migration_incoming_state_destroy(void) } if (mis->from_src_file) { + migration_ioc_unregister_yank_from_file(mis->from_src_file); qemu_fclose(mis->from_src_file); mis->from_src_file = NULL; } @@ -1811,6 +1813,7 @@ static void migrate_fd_cleanup(MigrationState *s) * Close the file handle without the lock to make sure the * critical section won't block for long. */ + migration_ioc_unregister_yank_from_file(tmp); qemu_fclose(tmp); } @@ -3351,8 +3354,17 @@ static MigThrError postcopy_pause(MigrationState *s) while (true) { QEMUFile *file; - /* Current channel is possibly broken. Release it. */ + /* + * Current channel is possibly broken. Release it. Note that this is + * guaranteed even without lock because to_dst_file should only be + * modified by the migration thread. That also guarantees that the + * unregister of yank is safe too without the lock. It should be safe + * even to be within the qemu_file_lock, but we didn't do that to avoid + * taking more mutex (yank_lock) within qemu_file_lock. TL;DR: we make + * the qemu_file_lock critical section as small as possible. + */ assert(s->to_dst_file); + migration_ioc_unregister_yank_from_file(s->to_dst_file); qemu_mutex_lock(&s->qemu_file_lock); file = s->to_dst_file; s->to_dst_file = NULL; diff --git a/migration/qemu-file-channel.c b/migration/qemu-file-channel.c index 2f8b1fc..bb5a575 100644 --- a/migration/qemu-file-channel.c +++ b/migration/qemu-file-channel.c @@ -107,9 +107,6 @@ static int channel_close(void *opaque, Error **errp) int ret; QIOChannel *ioc = QIO_CHANNEL(opaque); ret = qio_channel_close(ioc, errp); - if (OBJECT(ioc)->ref == 1) { - migration_ioc_unregister_yank(ioc); - } object_unref(OBJECT(ioc)); return ret; } diff --git a/migration/savevm.c b/migration/savevm.c index 96b5e5d..7b7b64b 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -65,6 +65,7 @@ #include "qemu/bitmap.h" #include "net/announce.h" #include "qemu/yank.h" +#include "yank_functions.h" const unsigned int postcopy_ram_discard_version; @@ -2568,6 +2569,12 @@ static bool postcopy_pause_incoming(MigrationIncomingState *mis) /* Clear the triggered bit to allow one recovery */ mis->postcopy_recover_triggered = false; + /* + * Unregister yank with either from/to src would work, since ioc behind it + * is the same + */ + migration_ioc_unregister_yank_from_file(mis->from_src_file); + assert(mis->from_src_file); qemu_file_shutdown(mis->from_src_file); qemu_fclose(mis->from_src_file); diff --git a/migration/yank_functions.c b/migration/yank_functions.c index 2369717..8c08aef 100644 --- a/migration/yank_functions.c +++ b/migration/yank_functions.c @@ -14,6 +14,7 @@ #include "qemu/yank.h" #include "io/channel-socket.h" #include "io/channel-tls.h" +#include "qemu-file.h" void migration_yank_iochannel(void *opaque) { @@ -46,3 +47,16 @@ void migration_ioc_unregister_yank(QIOChannel *ioc) QIO_CHANNEL(ioc)); } } + +void migration_ioc_unregister_yank_from_file(QEMUFile *file) +{ + QIOChannel *ioc = qemu_file_get_ioc(file); + + if (ioc) { + /* + * For migration qemufiles, we'll always reach here. Though we'll skip + * calls from e.g. savevm/loadvm as they don't use yank. + */ + migration_ioc_unregister_yank(ioc); + } +} diff --git a/migration/yank_functions.h b/migration/yank_functions.h index 74c7f18..a757795 100644 --- a/migration/yank_functions.h +++ b/migration/yank_functions.h @@ -17,3 +17,4 @@ void migration_yank_iochannel(void *opaque); void migration_ioc_register_yank(QIOChannel *ioc); void migration_ioc_unregister_yank(QIOChannel *ioc); +void migration_ioc_unregister_yank_from_file(QEMUFile *file); |