Attaching the patch to remove the deadcode MDEV-20638-10.2-e40ed0e881690ed072c28c0f4080a3cfb83e5d73v1.patch

This looks good to me, but I think that we can remove even more code:

• Remove srv_wake_master_thread() and invoke srv_inc_activity_count() instead.
• Simplify srv_master_thread further. Because srv_shutdown_state cannot change back to SRV_SHUTDOWN_NONE while the thread exists, the switch can be removed.
• Make parameter of srv_check_activity() in/out, removing the need of most calls to srv_get_activity_count().
• Do we need SRV_MASTER_SLOT and SRV_MASTER at all? What is the srv_reserve_slot(SRV_MASTER) good for?

Idea for srv_master_thread simplification:

	while (srv_shutdown_state == SRV_SHUTDOWN_NONE) {

		…

	}

	ut_ad(srv_shutdown_state == SRV_SHUTDOWN_EXIT_THREADS || srv_shutdown_state == SRV_SHUTDOWN_CLEANUP);

	…

	os_thread_exit();

}

Fixed all the review comments and patch is in bb-10.2-thiru. We need SRV_MASTER_SLOT, SRV_MASTER & srv_reserve_slot(SRV_MASTER) to make sure
that master thread exits before assigning SRV_SHUTDOWN_FLUSH_PHASE

Thank you for the update. I sent some comments. I think that any potentially functional changes must be documented in the commit message.

This looks OK, but you forgot to remove INNOBASE_WAKE_INTERVAL from extra/mariabackup/xtrabackup.cc and storage/innobase/handler/ha_innodb.cc. I can also spot some inadvertent changes to white space. The commit message should mention that srv_master_thread() does not need to call srv_resume_thread() and therefore there is no need to wake up the thread.