Messages in this thread |  | | | From | (Eric W. Biederman) | | Subject | Re: init's children list is long and slows reaping children. | | Date | Tue, 10 Apr 2007 10:17:56 -0600 |
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Ingo Molnar <mingo@elte.hu> writes:
> * Eric W. Biederman <ebiederm@xmission.com> wrote: > >> > so ... is anyone pursuing this? This would allow us to make >> > sys_wait4() faster and more scalable: no tasklist_lock bouncing for >> > example. >> >> which part? > > all of it :) Everything you mentioned makes sense quite a bit. The > thread signal handling of do_wait was added in a pretty arbitrary > fashion so i doubt there are strong requirements in that area. Apps > might have grown to get used to it meanwhile though, so we've got to do > it carefully.
I'm looking at. If only because there is a reasonable chance doing this will fix the races with a threaded init.
However I just found something nasty. The wait __WNOTHREAD flag.
And my quick search seems to find at least one user space applications that uses it, and it is widely documented so I suspect there are others :(
I played with moving the lists into signal_struct, and short of architecture specific users of task->children all I had to touch were:
include/linux/init_task.h | 2 +- include/linux/sched.h | 5 +- kernel/exit.c | 159 +++++++++++++++++++++------------------------ kernel/fork.c | 2 +- mm/oom_kill.c | 4 +- So it should be relatively easy to change this child lists around...
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