Providers

A memory provider returns current memory usage as a fraction in the inclusive range [0.0, 1.0].

The default provider selection is:

1. Linux cgroup-v2 accounting when the current process is in a cgroup-v2 hierarchy.
2. Linux /proc/meminfo.
3. sysinfo on non-Linux targets when the sysinfo feature is enabled.

Custom providers can implement MemoryProvider for other memory sources such as NUMA-specific accounting, container runtimes, or test fixtures.