3 ms·
Processes don't share mutable data, not without explicitly using IPC. In nearly all Unixes, both processes share their entire address spaces after the fork(),
by blasdel 17y ago
Processes don't share mutable data, not without explicitly using IPC.
In nearly all Unixes, both processes share their entire address spaces after the fork(), just immutably -- pages are only copied when they're written to by one of the processes, otherwise they are shared till exit. Copy-on-write is what makes fork() tractable performance-wise.
- easp 17y agoCopy-on-write is also why people overestimate Apache memory consumption so dramatically and then get into the hassle of running php apps under fcgi to save a trivial amount of memory.