Messages in this thread | | | From | (H. Peter Anvin) | Subject | Re: Killing clones | Date | 14 Aug 1997 19:10:17 GMT |
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Followup to: <Pine.LNX.3.95.970814090203.21030C-100000@vuser.vu.union.edu> By author: Rob Hagopian <hagopiar@vuser.vu.union.edu> In newsgroup: linux.dev.kernel > > > About a year ago a least was a a discussion about fixing up the > > CLONE_PID flag so that thread id's would be encoded in the upper bits of > > the pid. One could have ps list only the proc info for the initial > > thread (or other thread if the initial has exited), and be able to see > > what initial process all the threads are associated with. > > So if 32-bit [real] PIDs come around (there was talk of them appearing in > 2.1.x, and it's something I think a few people would like to see) then > we'd have 48 or 64 bit PIDs with thread info? > -Rob H. >
Note: there is actually no need for tid's to be allocated from a larger pool than pid's, although that may possibly allow some optimizations (I am not 100% convinced, since I think the kernel would have to validate all assumptions explicitly.)
You could very well allocate them out of the same number pool; if you do *not* specify CLONE_PID then you allocate both a pid and a tid, if you do, then you allocate a tid only. That would mean that tid's wouldn't "look" any different than pid's, but the kernel would still know.
For example: process - 47 threads - 48, 57, 122 process - 90 threads - 91, 94, 102, 107, 121 process - 92 threads - 93
(The last process being single-threaded.)
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