increase default shm_size

[staabm]

would it make sense to increase default shm_size?

apcu/php_apc.c

Line 142 in 33b40e0

STD_PHP_INI_ENTRY("apc.shm_size", "32M", PHP_INI_SYSTEM, OnUpdateShmSize, shm_size, zend_apcu_globals, apcu_globals)

it seems this value is way to less for a decent system nowadays.

[TysonAndre]

https://stackoverflow.com/questions/2782628/any-way-to-reserve-but-not-commit-memory-in-linux

Also, the memory will be reserved but not committed (virtual memory) on startup, at least on Linux with mmap, though I hadn't checked other platforms. So the impact on actual free memory is small until those parts of shared memory start getting used