The parjob plan generator split only maxTasks, so a job submitted with a
task range (minTasks < maxTasks) pended until all maxTasks tasks fit,
even when minTasks did (a tasks 2..5 job pended on a host with 2 free
slots).
The runner now handles a task range in sched_alloc_range_(): it probes
minTasks first and pends after that one search when it does not fit;
otherwise it places maxTasks when that fits, or binary-searches for the
largest count that fits and places it. Fitting is monotone in the count
for balanced plans, so the search is exact for today's plan shapes.
ctx->ntasks carries the count; parjob's job-level pass scales per-task
shared wants and global limits to it, and the generator gets the request
with its task count fixed to it. Fixed counts keep the old path.
The decision trace shows each count tried (task count N (minimum) /
(maximum), placing N tasks) and releases a fitting probe's hosts.
Test fixtures that used minTasks = 1 as filler for an N-task job are now
fixed-count.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
