libports is not (at least, not for now) a generalization / abstraction of Mach ports to the functionality the Hurd needs, that is, it is not meant to provide an interface independently of the underlying microkernel.
When a message is recieved, the thread acting as receiver checks if any other thread is also waiting for requests. If there is none, a new thread is spawned. Thus, the current thread continues processing the message while the newly created thread starts listening for new ones. (open issue hurd: multithreading.)
Also, there are configurable timeouts for translators who want to go away
when they are not used. (open issue hurd: there used to be bugs
in this area,
id:"firstname.lastname@example.org", but it may be
fixed as of
hurd/hurd.git commit 9b5429e834cde56f73b8ff605e36afc7d9bb6e1b.)
Several on the Open Issues page
IRC, freenode, #hurd, 2013-11-14
<teythoon> # portinfo $(pgrep mach-defpager) | tail -n 1 <teythoon> 16819001: receive <teythoon> is that normal ? <braunr> it can be, yes <braunr> port names can be renamed <braunr> there are a few occurrences in the code <braunr> see http://www.gnu.org/software/hurd/gnumach-doc/Port-Names.html#Port-Names <teythoon> I know <braunr> mach-defpager/default_pager.c: kr = mach_port_rename( default_pager_self, <teythoon> heh, it is a pointer <teythoon> I thought that'd make stuff inefficient in gnumach? <braunr> it does <braunr> such rights are moved from a regular fast-access table to a splay tree <braunr> but when i looked into it, there were never more than a few dozen rights in these trees <braunr> (which is why i didn't merge my radix tree in gnumach) <teythoon> I've been contemplating to replace the libihash usage in libports with a simple array <braunr> consider a radix tree too then :) <teythoon> well, I did <braunr> ok <teythoon> but I'm not convinced that it would do better than a simple array (or the current ihash implementation) <braunr> really ? <teythoon> what do you hope to gain? <braunr> i'm practically certain it would do better than the current ihash code <braunr> uh, speed <braunr> the problem with an array or a hash table is resizing <braunr> a well tuned radix tree (say 64 ot 512 items per node) can reduce to a simple array for the common case <teythoon> right <teythoon> but consider the use case <braunr> and scale very well for massive users such as file systems which can reach several hundred thousand rights <teythoon> hm <braunr> an array could be very efficient as well <braunr> i'm just concerned about resizing <teythoon> but this is a problem with the current implementation as well <braunr> sure <braunr> we're not considering keeping it anyway <braunr> this discussion is about array vs radix tree <braunr> the radix tree also has the advantage to efficiently deal with sparsely populated port name spaces <braunr> to some degree <braunr> which is probably what you're currently concerned with about this weird port name in defpager :) <teythoon> http://paste.debian.net/65780/ <teythoon> yes, but mach-defpager does not use libports <braunr> ok
See also discussion on deficiencies, X15, IRC, freenode, #hurd, 2013-11-14.