Document and log cases where max jobs per user or partition is
  equal or greater than the max jobs test. In that case, a single
  user can easily stop all backfill scheduling.

Fix for job "--contiguous" option that could cause job allocation/launch
    failure or slurmctld crash.
bug 2573

This reverts commit f559a55c.

constraints mattered in a job.

Details include:
A job doesn't request memory but the system is running
with CR_*MEMORY with no default memory limit and the job requests nodes
with features of different sizes.  Previously the order of constraints
mattered where the smaller memory node would need to be requested first
or the job would fail.

Bug 2608

Previous logic would get an account and/or QOS time limit and use
  that value to overwrite the incoming RPC's NO_VAL value, which
  would change a job's time limit when changing an unrelated
  field (e.g. priority, QOS, etc.).
bug 2610

Prevent use of NULL pointer and SEGV when changing a job's QOS when
  the slurmdbd is not configured.

Fix backfill scheduler race condition that could cause invalid pointer in
    select/cons_res plugin. Bug introduced in 15.08.9, commit:
    efd9d35e

The scenario is as follows
1. Backfill scheduler is running, then releases locks
2. Main scheduling loop starts a job "A"
3. Backfill scheduler resumes, finds job "A" in its queue and
   resets it's partition pointer.
4. Job "A" completes and tries to remove resource allocation record
   from select/cons_res data structure, but fails to find it because
   it is looking in the table for the wrong partition.
5. Job "A" record gets purged from slurmctld
6. Select/cons_res plugin attempts to operate on resource allocation
   data structure, finds pointer into the now purged data structure
   of job "A" and aborts or gets SEGV
Bug 2603

misleading.

canceled while launching.

Power/cray: Don't specify NID list to Cray APIs. If any of those nodes are
    not in a ready state, the API returned an error for ALL nodes rather than
    valid data for nodes in ready state.
bug 2332

and retries are done making the error message a little misleading.

rollup would effectively never run again.

bug 2575

and sort of bug 2596

There was a subtle bug in how tasks were bound to CPUs which could result
in an "infinite loop" error. The problem was various socket/core/threasd
calculations were based upon the resources allocated to a step rather than
all resources on the node and rounding errors could occur. Consider for
example a node with 2 sockets, 6 cores per socket and 2 threads per core.
On the idle node, a job requesting 14 CPUs is submitted. That job would
be allocted 4 cores on the first socket and 3 cores on the second socket.
The old logic would get the number of sockets for the job at 2 and the
number of cores at 7, then calculate the number of cores per socket at
7/2 or 3 (rounding down to an integer). The logic layouting out tasks
would bind the first 3 cores on each socket to the job then not find any
remaining cores, report the "infinite loop" error to the user, and run
the job without one of the expected cores. The problem gets even worse
when there are some allocated cores on a node. In a more extreme case,
a job might be allocated 6 cores on one socket and 1 core on a second
socket. In that case, 3 of that job's cores would be unused.
bug 2502

This is a revision to commit 1ed38f26
The root problem is that a pthread is passed an argument which is
a pointer to a variable on the stack. If that variable is over-written,
the signal number recieved will be garbage, and that bad signal
number will be interpretted by srun to possible abort the request.

The previous commit obviously fixed a problem, but introduced a different
set of problems. This will be pursued later, perhaps in version 16.05.

With some configurations and systems, errors of the following sort were
occuring:
task/cgroup: task[1] infinite loop broken while trying to provision compute elements using block
task/cgroup: task[1] unable to set taskset '0x0'

burst_buffer/cray - If the pre-run operation fails then don't issue
    duplicate job cancel/requeue unless the job is still in run state. Prevents
    jobs hung in COMPLETING state.
bug 2587

Running "scontrol reconfig" releases resources for jobs waiting for
  the completion of Node Health Check so that other jobs can run.
  Cray says to always wait for NHC to complete, but in extreme
  cases that can be 2 hours, during which the entire resource
  allocation for a job may be unusable. Per advice from NERSC,
  the logic to release resources is unchanged, but logging is
  added here.

isn't kept up to date in the cache.

as will.

Fix gang scheduling resource selection bug which could prevent multiple jobs
    from being allocated the same resources. Bug was introduced in 15.08.6,
    commit 44f491b8

Here's how to reproduce on smd-server with 2 sockets, 6 cores per
socket and 2 threads per core, just run the following command line
3 times in quick succession (all active at the same time):
srun --cpus-per-task=4 -m block sleep 30
What was happening is the first job would be allocated cores 0+1
The second job would be allocated cores 2+3
The thrid job would test use of cores 0-3 then exit because the
 job only needs 4 CPUs. The resulting core binding would include
 NO CPUs. The new logic tests that the core being considered for
 use actually has some resources available to the job before
 updating the counter which is being tested against the needed
 CPU counter.

Specifically add the HWLOC_TOPOLOGY_FLAG_WHOLE_SYSTEM flag when
loading configuration from HWLOC library. Previous logic in
task/cgroup did not do this, which was different behaviour from
how slurmd gets configuration information. Here's the HWLOC
documentation:
HWLOC_TOPOLOGY_FLAG_WHOLE_SYSTEM
Detect the whole system, ignore reservations and offline settings.
Gather all resources, even if some were disabled by the administrator.
For instance, ignore Linux Cpusets and gather all processors and memory
nodes, and ignore the fact that some resources may be offline.

Without this flag, I was rarely observing a bad core count, which
resulted in the logic layout out tasks wrong and generating an error:
task/cgroup: task[0] infinite loop broken while trying to provision compute elements using cyclic

bug 2502