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[PATCH v2 08/11] migration: Add migration_rp_wait|kick()
From: |
Peter Xu |
Subject: |
[PATCH v2 08/11] migration: Add migration_rp_wait|kick() |
Date: |
Tue, 12 Sep 2023 18:21:42 -0400 |
It's just a simple wrapper for rp_sem on either wait() or kick(), make it
even clearer on how it is used. Prepared to be used even for other things.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
migration/migration.h | 15 +++++++++++++++
migration/migration.c | 4 ++--
migration/ram.c | 16 +++++++---------
3 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/migration/migration.h b/migration/migration.h
index 48322e909e..311334c701 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -304,6 +304,12 @@ struct MigrationState {
* be cleared in the rp_thread!
*/
bool rp_thread_created;
+ /*
+ * Used to synchronize between migration main thread and return
+ * path thread. The migration thread can wait() on this sem, while
+ * other threads (e.g., return path thread) can kick it using a
+ * post().
+ */
QemuSemaphore rp_sem;
/*
* We post to this when we got one PONG from dest. So far it's an
@@ -516,4 +522,13 @@ void migration_populate_vfio_info(MigrationInfo *info);
void migration_reset_vfio_bytes_transferred(void);
void postcopy_temp_page_reset(PostcopyTmpPage *tmp_page);
+/* Migration thread waiting for return path thread. */
+void migration_rp_wait(MigrationState *s);
+/*
+ * Kick the migration thread waiting for return path messages. NOTE: the
+ * name can be slightly confusing (when read as "kick the rp thread"), just
+ * to remember the target is always the migration thread.
+ */
+void migration_rp_kick(MigrationState *s);
+
#endif
diff --git a/migration/migration.c b/migration/migration.c
index 216d0e871f..b958ac8743 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1846,7 +1846,7 @@ static int migrate_handle_rp_resume_ack(MigrationState *s,
MIGRATION_STATUS_POSTCOPY_ACTIVE);
/* Notify send thread that time to continue send pages */
- qemu_sem_post(&s->rp_state.rp_sem);
+ migration_rp_kick(s);
return 0;
}
@@ -2514,7 +2514,7 @@ static int postcopy_resume_handshake(MigrationState *s)
qemu_savevm_send_postcopy_resume(s->to_dst_file);
while (s->state == MIGRATION_STATUS_POSTCOPY_RECOVER) {
- qemu_sem_wait(&s->rp_state.rp_sem);
+ migration_rp_wait(s);
}
if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
diff --git a/migration/ram.c b/migration/ram.c
index a9541c60b4..b5f6d65d84 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -4157,7 +4157,7 @@ static int ram_dirty_bitmap_sync_all(MigrationState *s,
RAMState *rs)
/* Wait until all the ramblocks' dirty bitmap synced */
while (qatomic_read(&rs->postcopy_bmap_sync_requested)) {
- qemu_sem_wait(&s->rp_state.rp_sem);
+ migration_rp_wait(s);
}
trace_ram_dirty_bitmap_sync_complete();
@@ -4165,11 +4165,6 @@ static int ram_dirty_bitmap_sync_all(MigrationState *s,
RAMState *rs)
return 0;
}
-static void ram_dirty_bitmap_reload_notify(MigrationState *s)
-{
- qemu_sem_post(&s->rp_state.rp_sem);
-}
-
/*
* Read the received bitmap, revert it as the initial dirty bitmap.
* This is only used when the postcopy migration is paused but wants
@@ -4252,10 +4247,13 @@ int ram_dirty_bitmap_reload(MigrationState *s, RAMBlock
*block, Error **errp)
qatomic_dec(&rs->postcopy_bmap_sync_requested);
/*
- * We succeeded to sync bitmap for current ramblock. If this is
- * the last one to sync, we need to notify the main send thread.
+ * We succeeded to sync bitmap for current ramblock. Always kick the
+ * migration thread to check whether all requested bitmaps are
+ * reloaded. NOTE: it's racy to only kick when requested==0, because
+ * we don't know whether the migration thread may still be increasing
+ * it.
*/
- ram_dirty_bitmap_reload_notify(s);
+ migration_rp_kick(s);
ret = 0;
out:
--
2.41.0
- [PATCH v2 00/11] migration: Better error handling in rp thread, allow failures in recover, Peter Xu, 2023/09/12
- [PATCH v2 01/11] migration: Display error in query-migrate irrelevant of status, Peter Xu, 2023/09/12
- [PATCH v2 02/11] migration: Let migrate_set_error() take ownership, Peter Xu, 2023/09/12
- [PATCH v2 05/11] migration: Deliver return path file error to migrate state too, Peter Xu, 2023/09/12
- [PATCH v2 04/11] migration: Refactor error handling in source return path, Peter Xu, 2023/09/12
- [PATCH v2 08/11] migration: Add migration_rp_wait|kick(),
Peter Xu <=
- [PATCH v2 03/11] migration: Introduce migrate_has_error(), Peter Xu, 2023/09/12
- [PATCH v2 06/11] qemufile: Always return a verbose error, Peter Xu, 2023/09/12
- [PATCH v2 07/11] migration: Remember num of ramblocks to sync during recovery, Peter Xu, 2023/09/12
- [PATCH v2 09/11] migration: Allow network to fail even during recovery, Peter Xu, 2023/09/12
- [PATCH v2 11/11] tests/migration-test: Add a test for postcopy hangs during RECOVER, Peter Xu, 2023/09/12
- [PATCH v2 10/11] migration: Allow RECOVER->PAUSED convertion for dest qemu, Peter Xu, 2023/09/12