Re: [libvirt] [PATCH] Add APIs for killing off processes inside a cgroup
On Wed, Feb 23, 2011 at 03:26:30PM +0800, Daniel Veillard wrote:
On Tue, Feb 22, 2011 at 11:17:05AM -0700, Eric Blake wrote:
> On 02/22/2011 10:55 AM, Daniel P. Berrange wrote:
> > The virCgroupKill method kills all PIDs found in a cgroup
> >
> > The virCgroupKillRecursively method does this recursively
> > for child cgroups.
> >
> > The virCgroupKillPainfully method does a recursive kill
> > several times in a row until everything has really died
>
> Do we really need three APIs, or can we just have:
>
> virCgroupKill(..., VIR_CGROUP_KILL_RECURSIVE | VIR_CGROUP_KILL_PAINFUL)
>
> I haven't reviewed the body of the patch, yet.
Agreed, I was surpized by this at first.
Went though the patch my only remarks are
rc = killedAny ? 1 : 0;
is overkill since killedAny values seems only 0 or 1 anyway
and the loop for virCgroupKillPainfully looks a bit arbitrary,
sending 15 signals to all looks a lot, and the delay for the loop
a bit short, if there is like a hundred processes in that group that
could be a bit heavy, isn't it ?
The apporach & timings I'm following here are the same as that used
in systemd, and the only way a process could not die after the
SIGKILL is if the kernel had it in an uninterruptable sleep. So I
think this is sufficient for our needs - it certainly is dramatically
more reliable than the code it is replacing in LXC :-)
Daniel
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