idea to enhance get_pid()
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Quoted 3 lines · Dan Aloni
The last time I checked, the only thing that stops the move back to 32-bit pids is a bug in the bash shell, and just a few workable IPC interfaces and libc breakages.
I'd like to know more about that bash bug; do you have a URL for it? (Is there even a bug tracking system for bash?)
I looked a bit on gnu.bash.bugs, and found two possibly related patches; do these have anything to do with the bug?
http://groups.google.com/groups?selm=200104130734.AAA12931%40shade.twinsun.com
http://groups.google.com/groups?selm=200104130854.BAA18368%40shade.twinsun.com
Thanks,
Dan
32-bit process ids (was: Re: idea to enhance get_pid())
Quoted 6 lines · Dan Kegel
I'd like to know more about that bash bug; do you have a URL for it? (Is there even a bug tracking system for bash?)
I looked a bit on gnu.bash.bugs, and found two possibly related patches; do these have anything to do with the bug?
http://groups.google.com/groups?selm=200104130734.AAA12931%40shade.twinsun.com
http://groups.google.com/groups?selm=200104130854.BAA18368%40shade.twinsun.com
In a post by Linus from 2 years ago, concerning the bash bug ( http://lwn.net/2000/0120/a/lt-pid.html ), he also writes about what holds from switching to 32 bit pids. and it's mainly because it's unclear about the way pids should be handled in a clustering environment.
According to the kernel patch made by the people at Cluster Infrastructure ( http://ci-linux.sourceforge.net/ ), today it is clear that the upper 16 bits of the pid are used for the node number.
Linus should consider applying Andries Brouwer's patch from October:
( http://marc.theaimsgroup.com/?l=linux-kernel&m=100274734125520&w=2 ) This is really 2.5 material, but it slipped away for no apparent reason.
Re: 32-bit process ids (was: Re: idea to enhance get_pid())
Quoted 4 lines
According to the kernel patch made by the people at Cluster Infrastructure ( http://ci-linux.sourceforge.net/ ), today it is clear that the upper 16 bits of the pid are used for the node number.
This is the one thing I let through back in 1984. Nixdorff wanted to use parts of the processID for processorID. Now I don't have my authors' copy of XPG/1 CAE anymore, but I still have a lasting sense of chagrin that as trivially exhausted resource as a pid had bits shaved off for mid-80s SMP machines. Granted, our pid_t of the time was 16 bits, and an Intel HyperCube made a big dent in the remaining bits-for-pid'ing, and current pid_t's on 32-bit boxen is is 32 bits, and MPP boxes are few and far between -- but really large clusters are possible.
$.02
Eric