Re: [PATCH v3 5/5] cpusets, suspend: Save and restore cpusetsduring suspend/resume

From: Peter Zijlstra
Date: Tue May 15 2012 - 17:13:46 EST


On Tue, 2012-05-15 at 14:05 -0700, David Rientjes wrote:
> Not sure what you're disagreeing with, it only happens with
> MPOL_F_STATIC_NODES or MPOL_F_RELATIVE_NODES and I've clearly defined the
> behavior in the man page. I personally never had a use-case for
> MPOL_F_RELATIVE_NODES but Paul Jackson asked that it be added for SGI when
> we added mempolicy mode flags.

So what you're saying is that:

task t: set_mempolicy(,mask=2-3);

add t to cpuset A

A.mems = 0-1
A.mems = 0-n

At which point t will again have 2-3, right?

My objection is that you'll have to keep the 2-3 mask around some place
because t->mems_allowed will be wrecked by cpuset actions.

Also, what does it mean to silently return to 2-3 after you've broken
that promise by forcing it to 0-1 using cpusets?


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