(4/4/12 10:49 AM), Ulrich Drepper wrote:
On Wed, Apr 4, 2012 at 13:07, KOSAKI Motohiro<kosaki.motohiro@xxxxxxxxx> wrote:
Umm... I'm sorry. I haven't catch why OOM is related topic. Could you please
elaborate more?
With fork you always have some copy-on-write (and worse for
overcommit) just to then execute exec. With a real spawn
implementation you wouldn't have that. A big problem if you, for
instance, have to spawn a small helper from a gigantic process.
Ah, ok. I agree posix_spawn() has a chance to aim more momemory efficiency
than fork-exec. But in this purpose, vfork may be enough useful and be widely
accepted from userland folks.
Example, some daemon has a following patten,
1. fork
2. change /proc/<pid>/oom_adj
3. exec
That's said, when adding linux specific knob, we need to add new posix_spawn flags
if we really need (or want) to replaces all userland. this seems very hard and doubtful
worth to me.
Ahh, note. I'm not against to implement posix_spawn() into the kernel. I only argue spawn()
can solve closefrom issue.
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