MPS issue job003944

TitleArena allocation policy may allocate in blacklisted zone
Assigned userNick Barnes
DescriptionWhen trying to allocate a tract in an arena, we attempt a series of methods (see design/strategy#.policy.alloc.impl): Plan A looks in non-blacklisted preferred zones. Plan B looks in preferred zones plus non-blacklisted free zones. Plan C attempts to grow the arena and, if that succeeds, retries plan A and plan B. Plan D looks in all non-blacklisted zones. Plan E looks in all zones. However: (a) if plan C fails to grow the arena, the allocation attempt fails: plans D and E are not attempted. (b) plan B may allocate in a blacklisted zone (if it is included in the preferred zones); this is probably a mistake and blacklisted zones should be put off until the bitter end in plan E. (c) How many of these plans to attempt should probably be controlled somehow - for instance so it can interact with the reserve pool.
Analysis(a) and (b) are pretty easy to fix. (c) is much harder and open-ended and probably deserves its own job.
(a) is covered by job003898, which is fixed.
(c) now split into job003954.
This job is now just (b), which is unlikely to occur.
How foundinspection
Created byNick Barnes
Created on2015-09-09 15:17:55
Last modified byRichard Brooksby
Last modified on2016-02-27 00:22:24
History2015-09-09 NB Created.
2015-02-27 RB Splitting job and removing duplicate. Downgrading to optional.