I want some of them callbacks!
Posted Nov 2, 2002 21:15 UTC (Sat) by
bronson (subscriber, #4806)
In reply to:
I want some of them callbacks! by zooko
Parent article:
sys_epoll - making poll fast
Maybe IkeTo gave too comprehensive an answer...
Is it too tricky to have the kernel change to user context and invoke a function pointer that I have given it?
Yes.
Whenever the kernel calls user code directly, non-obvious and non-trivial race conditions result. It's a very difficult problem. Much easier to just have the system call return, and then the user can deal with the callbacks however she/he wants.
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