Inside a container, sysconf(_SC_NPROCESSORS_ONLN) and sysinfo() report
the host's CPU count and RAM, not the cgroup's effective quota — so
cbm_default_worker_count over-provisions workers and the mmap budget can
exceed the cgroup memory cap, driving OOMKills (#363).
detect_system_linux now reads the cgroup limits:
- cbm_detect_cgroup_cpus: cgroup v2 cpu.max, then v1 cpu.cfs_quota_us /
cpu.cfs_period_us → ceil(quota/period); -1 when unlimited.
- cbm_detect_cgroup_mem: cgroup v2 memory.max, then v1
memory.limit_in_bytes; 0 when unlimited or the v1 near-ULLONG_MAX
sentinel.
- Effective value is min(cgroup, host), guarding against mis-mounted
cgroups that report more than the host.
Helpers read via a bounded read_small_file (fopen "re", capped fread)
and are exposed through system_info_internal.h for unit tests that drive
them against a fake cgroup tree. The test teardown uses opendir/unlink/
rmdir (no shell spawn).
Distilled from #365 onto current main (unioned the test additions with
the CBM_WORKERS tests from #364, and replaced the test-cleanup
system("rm -rf") with a shell-free recursive remove). Closes#363
together with #364.
Sam Li
a5a3d1d60a