This patch introduces: - multithreading of syncop processors permitting synctasks to be executed concurrently if the runqueue has many tasks. - Auto scaling of syncop processors based on runqueue length. - Execute a synctask (synctask_new) in a blocking way if callback function is set NULL. The return value of the syncfn will be the return value of synctask_new() Change-Id: Iff369709af9adfd07be3386842876a24e1a5a9b5 BUG: 763820 Reviewed-on: http://review.gluster.com/443 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Anand Avati <avati@redhat.com>