GitLab

- modules now receive a memory buffer after successfully
registering with darshan-core. modules can request a specific
memory amount, but may not be honored depending on the configured
darshan memory limit
- split the previous register_record function into 2 parts:
    * lookup() -> lookup darshan_record_id corresp. to path name
    * register() -> register record_id & name with darshan-core
- register_record now returns true if the record added; false
otherwise (if module was out of memory or darshan is out of memory
for storing id->name mappings)

Now, as the app executes, darshan-core persists the id->name
mapping data to the tmp log file. This is done by serializing the
id->name mapping to the mmap log file region when new records are
registered.

user can now give a config option or use a runtime environment
variable to control darshan's per module memory requirements.

use --with-max-records at configure time to change from default
of 2048 records

-darshan-core:
    - initializes darshan job data structures
    - creates log file
    - writes job info header
    - reduces which modules were used locally/globally
    - shut down and write out individual modules one by one

-darshan-posix:
    - register w/ darshan-core and allocate allowed memory
    - track open counter and timestamp for opened files
    - provide file record buffer at shutdown

Major TODOs:
    - shared file reductions (prefer reusable across modules)
    - register handles with darshan file_ids (prefer reusable)
    - generic compression of module buffers (zlib/bzip2)
    - write out map of filenames to darshan ids
    - modify darshan-util and add darshan-posix parser to read logs

-also, darshan core uses utlist to keep track of modules

New darshan-core source files which intercept MPI init/finalize,
initialize darshan job information, and first attempt at a POSIX
module.