Re: [PATCH] oom: add sysctl to enable slab memory dump

From: Christoph Lameter
Date: Wed Feb 22 2012 - 11:29:43 EST


On Wed, 22 Feb 2012, Rafael Aquini wrote:

> On Wed, Feb 22, 2012 at 07:55:16AM -0600, Christoph Lameter wrote:
> >
> > Please use node_nr_objects() instead of directly accessing total_objects.
> > total_objects are only available if debugging support was compiled in.
> >
> Shame on me! I've wrongly assumed that it would be safe accessing
> the element because SLUB_DEBUG is turned on by default when slub is chosen.
>
> Considering your note on my previous mistake, shall I assume now that it
> would be better having this whole dump feature dependable on CONFIG_SLUB_DEBUG,
> instead of just CONFIG_SLUB ?

That is certainly one solution. If CONFIG_SLUB_DEBUG is not set then
support for maintaining a total count is not compiled in. You can of
course still approximate that from the total number of slabs allocated and
multiply that number by the # of objs per slab page.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/