Re: [PATCH 2/4] coredump: speedup SIGKILL sending

[Lee Revell]

On Fri, 2006-04-07 at 03:55 +0400, Oleg Nesterov wrote:
> On 04/06, Lee Revell wrote:
> > On Fri, 2006-04-07 at 02:06 +0400, Oleg Nesterov wrote:
> > > With this patch a thread group is killed atomically under ->siglock.
> > > This is faster because we can use sigaddset() instead of force_sig_info()
> > > and this is used in further patches.
> > > 
> > > Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> > 
> > Won't this cause huge latencies when a process with lots of threads is
> > killed?
> 
> Yes, irqs are disabled. But this is not worse than 'kill -9 pid', note
> that __group_complete_signal() or zap_other_threads() do the same.

Those have been problematic in the past.  I am just wondering if this
will be a latency regression, or if changes elsewhere in your patch
negate the effect.

I'm just concerned because it was a lot of work over ~2 years to get 2.6
to perform decently in this area, and we have regressed since 2.6.14 (VM
issue).

Lee

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