Messages in this thread | | | From | Con Kolivas <> | Subject | Re: [2.6.16-rc6 patch] fix interactive task starvation | Date | Sat, 18 Mar 2006 19:15:47 +1100 |
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On Saturday 18 March 2006 19:05, Andrew Morton wrote: > Mike Galbraith <efault@gmx.de> wrote: > > The patch below fixes a starvation problem that occurs when a stream of > > highly interactive tasks delay an array switch for extended periods > > despite EXPIRED_STARVING(rq) being true. AFAIKT, the only choice is to > > enqueue awakening tasks on the expired array in this case. > > > > Without this patch, it can be nearly impossible to remotely login to a > > busy server, and interactive shell commands can starve for minutes. > > > > This has not been verified by anyone. Comments? > > What does that question mean, btw?
He's waiting for me to say I don't like it. But I do like it.
> -mm is looking like linux-2.6.38 at present so of course things got tangled > up - sched-activate-sched-batch-expired.patch modifies __activate_task(). > > I ended up with the below. > > Which do we think is more likely to be true - batch_task(p) or > expired_starving(rq)? batch_task() looks cheaper to evaluate so I put that > first. But I guess it's less likely to be true. hmm.
Depends entirely on workload so it's impossible to predict in advance. Any order will do I suspect.
> + if (unlikely(batch_task(p) || expired_starving(rq)))
Looks good to me.
Acked-by: Con Kolivas <kernel@kolivas.org>
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