Allowing small allocations to fail

Posted Mar 12, 2015 7:55 UTC (Thu) by dlang (guest, #313)
In reply to: Allowing small allocations to fail by epa
Parent article: Allowing small allocations to fail

many servers don't have any local storage (I forgot to add the hypervisor layer in my example to top things off)

Personally, I operate servers with minimal or no swap, but the people who are screaming about how evil overcommit and copy-on-write are need to have a LOT of swap so that they can pretend that it's real memory when a program forks.

Oh, by the way, they are still betting that it's never going to be needed, because if it actually was needed, the system would be unusable. I'd rather have a system fail, even if it triggers the OOM killer (which does log what it's doing, so my central log system can detect failures, including the failure of the log forwarder), rather than slow to a crawl but still appear to be working.

Allowing small allocations to fail

Posted Mar 13, 2015 7:03 UTC (Fri) by epa (subscriber, #39769) [Link] (2 responses)

...and so we come back to fork() being the wrong tool for the job 90% of the time (since most fork() is just a precursor to exec()) and how userspace should use posix_spawn() instead where possible, except that sometimes you need to do extra manipulations in the child process before exec(), but even then a whole copy of the parent's address space is not usually needed...

Allowing small allocations to fail

Posted Mar 17, 2015 18:54 UTC (Tue) by nix (subscriber, #2304) [Link] (1 responses)

posix_spawn() is insanely complex, hard to use, very *rarely* used and has as a result had serious bugs in the past. It's best avoided unless you expect your program to be useful on a box without an MMU.

Allowing small allocations to fail

Posted Mar 18, 2015 9:58 UTC (Wed) by cesarb (subscriber, #6266) [Link]

> It's best avoided unless you expect your program to be useful on a box without an MMU.

Isn't it also useful if you expect your program to be ported to operating systems without fork()/exec() (Windows) or operating systems where the GUI libraries don't like fork() (from what I've heard, this is the case on Mac)?