Messages in this thread | | | From | Colin Walters <> | Subject | Re: [RFC] EPOLL_KILLME: New flag to epoll_wait() that subscribes process to death row (new syscall) | Date | Wed, 01 Nov 2017 11:16:37 -0400 |
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On Wed, Nov 1, 2017, at 01:32 AM, Shawn Landden wrote: > It is common for services to be stateless around their main event loop. > If a process passes the EPOLL_KILLME flag to epoll_wait5() then it > signals to the kernel that epoll_wait5() may not complete, and the kernel > may send SIGKILL if resources get tight. >
I've thought about something like this in the past too and would love to see it land. Bigger picture, this also comes up in (server) container environments, see e.g.:
https://docs.openshift.com/container-platform/3.3/admin_guide/idling_applications.html
There's going to be a long slog getting apps to actually make use of this, but I suspect if it gets wrapped up nicely in some "framework" libraries for C/C++, and be bound in the language ecosystems like golang we could see a fair amount of adoption on the order of a year or two.
However, while I understand why it feels natural to tie this to epoll, as the maintainer of glib2 which is used by a *lot* of things; I'm not sure we're going to port to epoll anytime soon.
Why not just make this a prctl()? It's not like it's really any less racy to do:
prctl(PR_SET_IDLE) epoll()
and this also allows:
prctl(PR_SET_IDLE) poll()
And as this is most often just going to be an optional hint it's easier to e.g. just ignore EINVAL from the prctl().
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