Module memory 

How much memory this process uses, and giving freed memory back to the system.

process_memory reads the numbers the OS’s own tools show: on macOS the footprint (Activity Monitor’s “Memory” column, footprint <pid>: dirty private memory including compressed and GPU memory the process owns) and the resident size; on Linux the private resident plus swapped memory and the resident size (/proc/self/status); on Windows the private commit and the working set. Where the OS keeps it, it also gives the highest footprint since the process started, so a short spike between two readings still counts. thread_count says how many threads the process runs.

release_free_memory asks the allocator to return pages it holds free. Where that works (glibc’s malloc_trim) it shrinks the process at once. On macOS it does nothing: the system call for it (malloc_zone_pressure_relief) releases next to nothing (measured: 0–49 KB after freeing gigabytes): the default allocator keeps freed small and medium regions dirty for reuse and the kernel takes them back by itself over the next 30–60 s. A process started with MallocSpaceEfficient=1 in its environment hands freed regions back at once (a bundled app sets it through LSEnvironment in its Info.plist); space_efficient_malloc says whether this one was. Call it after dropping caches, not per frame.

	macOS	Linux	Windows	Web
process_memory	proc_pid_rusage	/proc/self/status	GetProcessMemoryInfo	None
peak	lifetime max footprint	– (None)	PeakPagefileUsage	None
thread_count	proc_pidinfo	/proc/self/status	toolhelp snapshot	None
release_free_memory	no-op (see above)	malloc_trim (glibc)	no-op	no-op

Structs

ProcessMemory

Memory of this process, in bytes.

Functions

process_memory

This process’s memory, or None where the platform has no way to ask (the web) or the call failed.

release_free_memory

Return the allocator’s free pages to the system where the allocator can (glibc’s malloc_trim). Returns the bytes released where the allocator says; 0 everywhere today (macOS has nothing that works, see the module docs; glibc does not say).

space_efficient_malloc

Whether macOS’s allocator runs in its space-efficient mode (MallocSpaceEfficient=1 in the environment the process started with), which returns freed memory to the system at once. Always false elsewhere.

thread_count

How many threads this process runs, or None where the platform has no way to ask (the web) or the call failed.