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Date:   Fri, 16 Oct 2020 11:11:52 -0300
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc:     Xianting Tian <tian.xianting@h3c.com>, mike.marciniszyn@intel.com,
        dennis.dalessandro@intel.com, dledford@redhat.com,
        linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] IB/hfi1: Avoid allocing memory on memoryless numa node
Message-ID: <20201016141152.GC36674@ziepe.ca>
References: <20201010085732.20708-1-tian.xianting@h3c.com>
 <9ba33073-044c-9da6-a90d-4626e6441793@cornelisnetworks.com>
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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@h3c.com>
> >   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.

Jason