Re: VFS: file-max limit 50044 reached

[Eric Dumazet]

Linus Torvalds a écrit :

> So I suspect that the _real_ fix is:
>
>  - for 2.6.14: remove the batching limig (or just make it much higher for 
>    now)

I would just remove it. If the limit is wrong, we crash again. And the 
realtime guys already are pissed off by batch=10000 anyway.

>  - post-14: work on making sure rcu callbacks are done in a more timely 
>    manner when the rcu queue gets long. This would involve TIF_RCUPENDING 
>    and whatever else to make sure that we have timely quiescent periods, 
>    and we do the RCU callback tasklet more often if the queue is long.

Absolutely. Keeping a count of (percpu) queued items is basically free if kept 
in the cache line used by list head, so the 'queue length on this cpu' is a 
cheap metric.

A 'realtime refinement' would be to use a different maxbatch limit depending 
on the caller's priority : Let a softirq thread have a lower batch count than 
a regular user thread.

Eric
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