Messages in this thread | | | From | Pedro Alves <> | Subject | Re: [rfc 2/3] fs, proc: Introduce the Children: line in /proc/<pid>/status | Date | Fri, 2 Dec 2011 13:40:11 +0000 |
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On Friday 02 December 2011 13:10:59, Pedro Alves wrote: > On Friday 02 December 2011 12:45:51, Cyrill Gorcunov wrote: > > On Fri, Dec 02, 2011 at 04:43:10PM +0400, Pavel Emelyanov wrote: > > ... > > > >> > > > >> Yes, I like /children file. other points seems to be pointed out by other > > > >> reviewers. > > > > > > > > Any reason this is a file instead of a directory like /proc/PID/task/ ? > > > > > > > > $ sudo ls /proc/8167/task/ > > > > 8167 854 855 856 857 858 859 > > > > $ sudo ls /proc/8167/task/855/ > > > > attr clear_refs cpuset exe io loginuid mountinfo oom_adj pagemap sched smaps statm wchan > > > > auxv cmdline cwd fd latency maps mounts oom_score personality schedstat stack status > > > > cgroup comm environ fdinfo limits mem numa_maps oom_score_adj root sessionid stat syscall > > > > > > > > Much easier to follow the chain from the command line this way. > > > > > > What do you propose to put into these directories? Another directories named with > > > children pid-s? > > > > > > > Yes, I suppose additional directory/links and whatever would be just > > noneeded overhead. > > /proc/8167/task/ being a directory could also be claimed > "noneeded overhead", yet it exists, and is very useful (I use > it a lot). Why diverge instead of being consistent?
Guess I should give an example. Here's one. While debugging gdb stuff, I often do:
$ cat /proc/8167/task/*/status | grep State State: S (sleeping) State: S (sleeping) State: S (sleeping) State: S (sleeping) State: S (sleeping) State: S (sleeping) State: S (sleeping)
If children were a directory (or "child", for consistency with singular "task"), you could do child things in the same natural way, like for instance:
$ ls -als /proc/8167/child/*/exe
It's like interactive pstree...
> (Note that listing /proc only shows thread group ids, but > you can still open /proc/THREAD-ID/, so a /proc/PID/task file > with lists of pids would have been "good enough".)
-- Pedro Alves
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