* Optimizations:
- Track mapping of missing object to dependent tasks to avoid iterating over task queue
- Perform all fetch requests for missing objects using the same timer
* Fix bug and add regression test
* Record task dependencies and active fetch requests in the same hash table
* fix typo
* Fix memory leak and add test cases for scheduling when dependencies are evicted
* Fix python3 test case
* Minor details.
* Split local scheduler task queue into waiting and dispatch queue
* Fix memory leak
* Add a new task scheduling status for when a task has been queued locally
* Fix global scheduler test case and add task status doc
* Documentation
* Address Philipp's comments
* Move tasks back to the waiting queue if their dependencies become unavailable
* Update existing task table entries instead of overwriting
* Object notification test for Photon, and turn on valgrind for Photon C tests
* Test object notification handler in the plasma manager
* Fix hanging test case
* Object reconstruction in Photon and C test cases for Photon
* Fix hanging test case on mac
* Remove unnecessary event from photon tests
* make photon_disconnect not leak file descriptors
* fix some of the memory errors
* Fix valgrind
* lint
* Address Robert's comments and add test case for object reconstruction suppression
* Remove OWNER
* Consolidate wait implementations.
* Consolidate fetch implementations.
* Share callback between wait and fetch to address issue in which only one callback can be run for a given subscribe channel.
* Reactivate manager tests.
* Remove more code.
* Add some documentation.
* Fetch missing dependencies from local scheduler.
* Factor out global scheduler policy state.
* Use object_table_subscribe instead of object_table_lookup.
* Fix bug in which timer was being created twice for a single fetch request.
* Free old manager vector.
* Use sizeof(field) instead of sizeof(type) and other fixes.
* Fix formatting.
* Bug fix.
* Zero-initialize structs. There are many more instances of these that I haven't changed yet.
* Bug fix.
* Revert from atexit to signaling to fix valgrind tests.
* Address Philipp's comments.
* Initial scheduler commit
* global scheduler
* add global scheduler
* Implement global scheduler skeleton.
* Formatting.
* Allow local scheduler to be started without a connection to redis so that we can test it without a global scheduler.
* Fail if there are no local schedulers when the global scheduler receives a task.
* Initialize uninitialized value and formatting fix.
* Generalize local scheduler table to db client table.
* Remove code duplication in local scheduler and add flag for whether a task came from the global scheduler or not.
* Queue task specs in the local scheduler instead of tasks.
* Simple global scheduler tests, including valgrind.
* Factor out functions for starting processes.
* Fixes.
* Set logging levels in Makefile using -DRAY_COMMON_LOG_LEVEL=level
* Lower level of some LOG_ERROR messages, log the name of the table operation on failure
* Address rest of Robert's comments
* Fix spurious log message
* Merge task table and task log
* Fix test in db tests
* Address Robert's comments and some better error checking
* Add a LOG_FATAL that exits the program
* Put infrastructure in place to compute task IDs and object IDs.
* Fix version number for common library.
* Compute task IDs and object IDs deterministically.
* Address Stephanie's comments.
* Update task documentation.
* Fix formatting.
* Add more tests and checks.
* Fix formatting.
* Enable DCHECKs and change CHECKs to DCHECKs.
* Update worker code and services code to use plasma and the local scheduler.
* Cleanups.
* Fix bug in which threads were started before the worker mode was set. This caused remote functions to be defined on workers before the worker knew it was in WORKER_MODE.
* Fix bug in install-dependencies.sh.
* Lengthen timeout in failure_test.py.
* Cleanups.
* Cleanup services.start_ray_local.
* Clean up random name generation.
* Cleanups.
* Ion and Philipp's table retries
* Refactor the retry struct:
- Rename it from retry_struct to retry_info
- Retry information contains the failure callback, not the retry callback
- All functions take in retry information as an arg instead of its expanded fields
* Rename cb -> callback
* Remove prints
* Fix compiler warnings
* Change some CHECKs to greatest ASSERTs
* Key outstanding callbacks hash table with timer ID instead of callback data pointer
* Use the new retry API for table commands
* Memory cleanup in plasma unit tests
* fix Robert's comments
* add valgrind for common
