Re: [PATCH] kdesu broken

From: Alan Cox
Date: Tue Jul 28 2009 - 14:56:53 EST


> My point is that a program _should_ be able to depend on simple causality
> when it comes to ordering rules. If the child did a write() before
> exiting, then we should see the data before SIGCHLD.
>
> It's really that simple.

In which case you need the write to be synchronous to the ldisc
processing. Which is what tty->low_latency = 1 did. That provides your
required causality.

So what exactly is the problem. Setting ->low_latency has a small
performance impact which was why I was trying the other stuff, but that
is all.

As I said tty->low_latency = 1 gives you the previous semantics.

Alan
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