Re: [PATCH] proc-based cpu affinity user interface

Davide Libenzi (davidel@xmailserver.org)
Tue, 27 Nov 2001 08:49:41 -0800 (PST)


On Tue, 27 Nov 2001, Ingo Molnar wrote:

>
> On Mon, 26 Nov 2001, Davide Libenzi wrote:
>
> > As I said in reply to Ingo patch, it'd be better to expose "number"
> > cpu masks not "logical" ( like cpus_allowed ). In this way the users
> > can use 0..N-1 ( N == number of cpus phisically available ) w/out
> > having to know the internal mapping between logical and number ids.
>
> yep, agreed. I've uploaded a new set-affinity syscall patch with your
> improvement added:
>
> http://redhat.com/~mingo/set-affinity-patches/set-affinity-2.4.16-A0
>
> i've only tested it on x86 which has a 1:1 mapping between physical and
> logical CPUs, but it should be fine on other architectures as well.

The snippet I sent yesterday should be corrected by checking if
cpu_{number,logical}_map(ii) is != -1 to avoid incorrect bit settings,
expecially from mask coming from user side.

- Davide

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