Add step_unconfigure_hardware() to GRES plugin API
Update test39.18 regarding links.
Update GRES docs.
Update docs related to links.
Document GPU frequency resetting behavior.
Specify what the default is for GpuFreqDef.
Move NVML init and shutdown to configure() and unconfigure().
Get rid of superfluous `!= 0`-style statements.
Print note when GPU index != minor number.
Clean up various formatting and other errors.

bug 5520

No functional change.

Due to upcoming changes in the X11 forwarding subsystem, support
for older-style X11 tunnels will be removed. Older client commands
cannot support the newer style. Rather than have the tunnel fail,
request the job allocation request up front.

Bug 3647.

Also tweak the one info() message here to match these others.

New X11 forwarding code will only support forwarding back to
salloc or an allocating srun command.

Using this option within sbatch was always hit-or-miss. If the
user submitting was disconnected from the alloc host for any
reason their xauth credentials would likely fail even if they
managed to get assigned the same local TCP port for forwarding.

Bug 3647.

< PAM_MAX_MSG_SIZE (which as of this date is 512)

In some systems there can be multiple user accounts for uid 0, therefore
the check for literal user name "root" might be insufficient.

Bug 6184

Using memcpy, an amount of undefined data from the stack will be copied
into the target buffer. While pam_conv probably doesn't evalute the
extra data it still unclean to do that. It could lead up to an
information leak somewhen.

This pam module is tailored towards running in the context of remote ssh
logins. When running in a different context like a local sudo call then
the module could be influenced by e.g. passing environment variables
like SLURM_CONF.

By limiting the module to only perform its actions when running in the
sshd context by default this situation can be avoided. An additional pam
module argument service=<service> allows an Administrator to control
this behavior, if different behavior is explicitly desired.

Bug 6184

Modify the functions in gres/mps to match changes implemented
in commit 5d40d5dc863446ff6

Add step_configure_hardware() to GRES plugin API.
Call step_configure_hardware() from stepd and make sure it's root.
Sort frequencies returned by NVML.
Update GRES-related docs.
Document step_configure_hardware() and get_devices().
Test the bubble sort algorithm.
Update test 39.9 to work with new code.
Remove vestigial references to volts in the docs.

Only print a warning for 18.08. If a user has SLURM_MEM_PER_CPU or
SLURM_MEM_PER_NODE environment variables set for some reason this
situation could be happening by accident, and we don't want to prevent
the srun command from launching steps at this point.

Bug 6058.

Bug 5648.

Remove restriction on port count previously added in 620f92f7.

gres_plugin_job_state_validate() modified in commit a44297e5
to add tres_freq field. This changes the test to match.

Disable request for both gres/mps and gres/gpu in a single request.
Also disable request for gres/mps and --gpu-freq,
disable mps-per-job with more than 1 node,
disable mps-per-socket with more than 1 socket, and
disable mps-per-task with more than 1 node.
Note these mps-per-* options are not currently available,
but data structures do exist to implement them.

The Linux kernel default hard limit of 4096 for the number of file
descriptors is quite small. Debian/Ubuntu have for a long time
overridden this, increasing it to 1M. Recently systemd also bumped the
default to 512k.

https://github.com/systemd/systemd/blob/master/NEWS

https://github.com/systemd/systemd/pull/10244

https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/ZN5TK3D6L7SE46KGXICUKLKPX2LQISVX/

https://github.com/systemd/systemd/commit/09dad04c49cae3ad2b319c9b4e7773fedd34309a

Here the limits are increased as follows:

- slurmd: 128k; some workloads like Hadoop/Spark need a lot of fd's,
  and recommend that the limit is increased to at least 64k.

- slurmctld: 64k; per the Slurm high throughput and big system guides
  which recommend a file-max of at least 32k.

- slurmdbd: 64k, matching slurmctld, though slurmdbd shouldn't need
  that many fd's, bumping the limit shouldn't hurt either.

Bug 6171

This makes it easier to pass string literals to slurm_perror(3).  For
example, a recent GCC emits the following when a string literal is passed
in C++:

   ISO C++ forbids converting a string constant to 'char*'

Bug 6082

Bug 5248

Bug 6055

Add the following slurmctld return codes to the lua plugin:

  ESLURM_ACCESS_DENIED
  ESLURM_ACCOUNTING_POLICY
  ESLURM_INVALID_NODE_COUNT
  ESLURM_JOB_MISSING_SIZE_SPECIFICATION
  ESLURM_MISSING_TIME_LIMIT

Bug 6055

Rework one timer error message while here.

Bug 5861.

Bug 6013

The GRES node information in slurmctld is now as we want it to be.
No job/step scheduling logic implemented yet.

Previous logic was printing a uint64_t as %lld and the test was
looking for a negative number. This corrects the test.

Test was sometimes failing due to delay in getting job accounting
data to database.

Use __func__, collapse message format to a single line as well.