Messages in this thread | | | Date | Wed, 2 Jul 2008 03:24:48 +0530 | From | Dhaval Giani <> | Subject | Re: Attaching PID 0 to a cgroup |
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On Tue, Jul 01, 2008 at 11:48:31PM +0200, Andrea Righi wrote: > Li Zefan wrote: >> CC: Paul Jackson <pj@sgi.com> >> >> Dhaval Giani wrote: >>> [put in the wrong alias for containers list correcting it.] >>> >>> On Tue, Jul 01, 2008 at 03:15:45PM +0530, Dhaval Giani wrote: >>>> Hi Paul, >>>> >>>> Attaching PID 0 to a cgroup caused the current task to be attached to >>>> the cgroup. Looking at the code, >>>> >> >> [...] >> >>>> I was wondering, why this was done. It seems to be unexpected behavior. >>>> Wouldn't something like the following be a better response? (I've used >>>> EINVAL, but I can change it to ESRCH if that is better.) >>>> >> >> Why is it unexpected? it follows the behavior of cpuset, so this patch will >> break backward compatibility of cpuset. >> >> But it's better to document this. >> >> ----------------------------------------- >> >> Document the following cgroup usage: >> # echo 0 > /dev/cgroup/tasks >> >> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> >> --- >> cgroups.txt | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/Documentation/cgroups.txt b/Documentation/cgroups.txt >> index 824fc02..213f533 100644 >> --- a/Documentation/cgroups.txt >> +++ b/Documentation/cgroups.txt >> @@ -390,6 +390,10 @@ If you have several tasks to attach, you have to do it one after another: >> ... >> # /bin/echo PIDn > tasks >> +You can attach the current task by echoing 0: >> + >> +# /bin/echo 0 > tasks >> + >> 3. Kernel API >> ============= > > Wouldn't be more meaningful to specify the bash's builtin echo here > even if it doesn't opportunely handle write() errors? > > Using /bin/echo would attach /bin/echo itself to the cgroup, that just > exists, so it seems like a kind of noop, isn't it? >
Yes, you are right. this example should use bash's builtin echo.
-- regards, Dhaval
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