Re: posible latency issues in seq_read

[Chris Friesen]

Lee Revell wrote:
> On 7/20/07, Chris Friesen <cfriesen@xxxxxxxxxx> wrote:

> > We've run into an issue (on 2.6.10) where calling "lsof" triggers lost
> > packets on our server.  Preempt is disabled, and NAPI is enabled.

> Can you reproduce with a recent kernel?  Lots of latency issues have
> been fixed since then.

Unfortunately I have to fix it on this version (the bug was found on 
shipped product), so if there was a difference I'd have to isolate the 
changes and backport them.  Also, I can't run the software that triggers 
the problem on a newer kernel as it has dependencies on various patches 
that are not in mainline.

Basically what I'd like to know is whether calling schedule() in 
seq_read() is safe or whether it would break assumptions made by 
seq_file users.

Chris
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