Re: [PATCH -mm] slub: document setting min order with debug_guardpage_minorder> 0

From: David Rientjes
Date: Tue Dec 13 2011 - 19:41:46 EST


On Tue, 13 Dec 2011, Rafael J. Wysocki wrote:

> > diff --git a/Documentation/ABI/testing/sysfs-kernel-slab b/Documentation/ABI/testing/sysfs-kernel-slab
> > index 8b093f8..d84ca80 100644
> > --- a/Documentation/ABI/testing/sysfs-kernel-slab
> > +++ b/Documentation/ABI/testing/sysfs-kernel-slab
> > @@ -345,7 +345,9 @@ Description:
> > allocated. It is writable and can be changed to increase the
> > number of objects per slab. If a slab cannot be allocated
> > because of fragmentation, SLUB will retry with the minimum order
> > - possible depending on its characteristics.
> > + possible depending on its characteristics.
>
> Added trailing whitespace (please remove).
>
> > + When debug_guardpage_minorder > 0 parameter is specified, the
> > + minimum possible order is used and cannot be changed.
>
> Well, I'm not sure what you wanted to say, actually? How does one change
> debug_guardpage_minorder (or specify it), for example? Is it a kernel
> command-line switch?
>

Yeah, we'll need a reference to Documentation/kernel-parameters.txt.

> Also I'm not sure what "cannot be changed" is supposed to mean. Does it
> mean that /sys/cache/slab/cache/order has no effect in that case?
>

Good point, we should say that "this tunable" cannot be used to change the
order at runtime if debug_guardpage_minorder is used on the command line.

Stanislaw, one more revision?
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