Re: [PATCH]: exec: avoid propagating PF_NO_SETAFFINITY intouserspace child

From: Oleg Nesterov
Date: Thu Nov 28 2013 - 11:06:48 EST


On 11/28, Oleg Nesterov wrote:
>
> On 11/28, Peter Zijlstra wrote:
> >
> > So there's three useful parts to having a single parent task:
> >
> > - its a task so you can change the entire task attribute set; current
> > and future.
>
> You can't change, say, its fs->root.
>
> OK, OK, this is almost off-topic, I am just trying to say that
> (perhaps) in the longer term we might want even more than just
> a dedicated kernel thread.
>
> > - new children will automatically get the desired attributes.
>
> yes,
>
> > - all children are easily identified by virtual of being children of
> > said parent process.
>
> Well, UMH_WAIT_PROC won't work in this case, or it will be "single-threaded"
> too. OK, this is probably solvable, but nontrivial. In this case "khelper"
> should act as a /sbin/init for user-mode helpers.

But I'm afraid I got lost...

I interpreted "having a single parent task" as "parent of all usermode
helpers".

If you actually meant that every wq thread should have a parent which
represents the workqueue, well, I disagree but I leave this to you and
Tejun again ;)

Oleg.

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