Code review comment for lp:~laurynas-biveinis/percona-server/xtradb-thread-priority-flag

Yes, UNIV_LINUX makes more sense than __GNUC__.

Re. isolation. The whole set of changes would be as follows, in the smallest parts:
- This MP.
- Priority mutex implementation.
- Specific buffer pool free list mutex conversion to priority.
- Non-specific mutex conversion to priority: dict_sys, LRU list, rseg, log.
- Priority rwlatch implementation.
- Non-specific rwlatch conversion to priority: fsp, page_hash, AHI, index, purge.

How this should be distributed among MPs? One big one with everything? Are separate commits OK or one big commit too?

Thanks.