Re: [PATCH 0/3] netfilter : 3 patches to boost ip_tables performance

[Christoph Hellwig <hch@infradead.org>]

On Thu, Sep 22, 2005 at 02:54:22PM +0200, Andi Kleen wrote:
> > > +void *vmalloc_node(unsigned long size, int node)
> > > +{
> > > +	void *result;
> > > +	struct mempolicy *oldpol = current->mempolicy;
> > > +	mm_segment_t oldfs = get_fs();
> > > +	DECLARE_BITMAP(prefnode, MAX_NUMNODES);
> > > +
> > > +	mpol_get(oldpol);
> > > +	bitmap_zero(prefnode, MAX_NUMNODES);
> > > +	set_bit(node, prefnode);
> > > +
> > > +	set_fs(KERNEL_DS);
> > > +	sys_set_mempolicy(MPOL_PREFERRED, prefnode, MAX_NUMNODES);
> > > +	set_fs(oldfs);
> > > +
> > > +	result = vmalloc(size);
> > > +
> > > +	mpol_free(current->mempolicy);
> > > +	current->mempolicy = oldpol;
> > > +	return result;
> > > +}
> >
> > No way, sorry.  If you want a vmalloc node do it right.
> 
> The implementation looks fine to me, so I think it's already right.

Umm, no - adding set_fs/get_fs mess for things like that is not right.
If we want to go down the mempolicy-based route we need to add a proper
kernel entry point for setting a mempolicy