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| -rw-r--r-- | microkernel/mach/continuation.mdwn | 24 | ||||
| -rw-r--r-- | open_issues/multithreading.mdwn | 3 |
2 files changed, 27 insertions, 0 deletions
diff --git a/microkernel/mach/continuation.mdwn b/microkernel/mach/continuation.mdwn new file mode 100644 index 00000000..7a3267f3 --- /dev/null +++ b/microkernel/mach/continuation.mdwn @@ -0,0 +1,24 @@ +[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] + +[[Mach]] internally uses *continuation*s for kernel [[thread]] management. + +The advantage is that not a full kernel thread stack has to be preserved in +case that a thread is about to enter a blocking state. This saves space. It +is not clear this is still worthwhile given today's RAM offerings. (How many +kernel threads are there, typically?) + +And, this would no longer be possible in case Mach were be made a +[[preemptive|preemtion]] kernel. In the latter case, the kernel itself, that +is, kernel threads can be preempted, and then their full state needs to be +preserved. + +[[!tag open_issue_documentation]] <!-- Not linked to from any Mach page. Move +to GNU Mach pages, as this is only an implementation detail? --> diff --git a/open_issues/multithreading.mdwn b/open_issues/multithreading.mdwn index 170734fd..39203333 100644 --- a/open_issues/multithreading.mdwn +++ b/open_issues/multithreading.mdwn @@ -22,6 +22,9 @@ Alternative approaches: * Continuation-passing style + * [[microkernel/Mach]] internally [[uses + continuations|microkernel/mach/continuation]], too. + * [[Erlang-style_parallelism]] * [libtcr - Threaded Coroutine Library](http://oss.linbit.com/libtcr/) |