ceph/ceph — pull request #2940 by xinxinsh (2014-11-17 06:40:34+00:00)
Title: Wip shard mapheaderlock

for every 4k random write , it will update pg epoch and pg info on OSDService::infos_oid , we find this transaction will be serialized on the infos_oid , which maybe not friendly to 4k random write performance, this patch will serialized the this transaction on an per-pg object , which will release the lock contention