On Wed, Jun 14, 2023 at 10:04 AM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote: > > Hi, > > 在 2023/06/14 9:48, Yu Kuai 写道: > > > >> > >> In the patch, sync_seq is added in md_reap_sync_thread. In > >> idle_sync_thread, if sync_seq isn't equal > >> > >> mddev->sync_seq, it should mean there is someone that stops the sync > >> thread already, right? Why do > >> > >> you say 'new started sync thread' here? > > If someone stops the sync thread, and new sync thread is not started, > then this sync_seq won't make a difference, above wait_event() will not > wait because !test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) will pass. > So 'sync_seq' is only used when the old sync thread stops and new sync > thread starts, add 'sync_seq' will bypass this case. Hi If a new sync thread starts, why can sync_seq be different? sync_seq is only added in md_reap_sync_thread. And when a new sync request starts, it can't stop the sync request again? Af first, the sync_seq is 0 admin1 echo idle > sync_action idle_sync_thread(sync_seq is 1) echo resync > sync_action (new sync) Then admin2 echos idle > sync_action, sync_seq is still 1 Regards Xiao > > Thanks, > Kuai >
