Table 1. mallopt() Parameters Mapped to Environment
mallopt() option
Env var
Default value
Notes
M_TRIM_THRESHOLD
MALLOC_TRIM_THRESHOLD_
128KB
-1U disables
M_TOP_PAD
MALLOC_TOP_PAD_
0
M_MMAP_THRESHOLD
MALLOC_MMAP_THRESHOLD_
128KB
0 disables
M_MMAP_MAX
MALLOC_MMAP_MAX_
64
0 disables