When the APCU extension is installed and PHP FPM is started, an error is reported: Note: PHP message: PHP fatal error: PHP startup: APC_ mmap: mmap failed: in Unknown on line 0

The reason is shm_size setting is too large.

Solution: Just set shm_size to make the size configuration smaller

As follows:
apc.shm_size=1024M

apc.shm_size=1024M