Re: [PATCH] IB/hfi1: Avoid allocing memory on memoryless numa node

[Dennis Dalessandro]

On 10/16/2020 10:11 AM, Jason Gunthorpe wrote:
> On Mon, Oct 12, 2020 at 08:36:57AM -0400, Dennis Dalessandro wrote:
> > On 10/10/2020 4:57 AM, Xianting Tian wrote:
> > > In architecture like powerpc, we can have cpus without any local memory
> > > attached to it. In such cases the node does not have real memory.
> > >
> > > Use local_memory_node(), which is guaranteed to have memory.
> > > local_memory_node is a noop in other architectures that does not support
> > > memoryless nodes.
> > >
> > > Signed-off-by: Xianting Tian <tian.xianting@xxxxxxx>
> > >    drivers/infiniband/hw/hfi1/file_ops.c | 2 +-
> > >    1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
> > > index 8ca51e43c..79fa22cc7 100644
> > > +++ b/drivers/infiniband/hw/hfi1/file_ops.c
> > > @@ -965,7 +965,7 @@ static int allocate_ctxt(struct hfi1_filedata *fd, struct hfi1_devdata *dd,
> > >    	 */
> > >    	fd->rec_cpu_num = hfi1_get_proc_affinity(dd->node);
> > >    	if (fd->rec_cpu_num != -1)
> > > -		numa = cpu_to_node(fd->rec_cpu_num);
> > > +		numa = local_memory_node(cpu_to_node(fd->rec_cpu_num));
> > >    	else
> > >    		numa = numa_node_id();
> > >    	ret = hfi1_create_ctxtdata(dd->pport, numa, &uctxt);
> >
> > The hfi1 driver depends on X86_64. I'm not sure what this patch buys, can
> > you expand a bit?
>
> Yikes, that is strongly discouraged.

Hmm. This was never raised as an issue before. Regardless I can't recall 
why we did this in the first place. I'll do some digging, try to jog my 
memory.

-Denny