ntb: Add a module option to control affinity of DMA channels

The DMA channel(s)/memory used to transfer data to an NTB device
may not be required to be on the same node as the device. Add a
module parameter that allows any candidate channel (aside from
node assocation) and allocated memory to be used.

Signed-off-by: Gary R Hook <gary.hook@amd.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

diff --git a/drivers/ntb/test/ntb_perf.c b/drivers/ntb/test/ntb_perf.c
index 42756a9..0ec9f56 100644 (file)
--- a/drivers/ntb/test/ntb_perf.c
+++ b/drivers/ntb/test/ntb_perf.c
@@ -101,6 +101,10 @@ static bool use_dma; /* default to 0 */
 module_param(use_dma, bool, 0644);
 MODULE_PARM_DESC(use_dma, "Using DMA engine to measure performance");
 
+static bool on_node = true; /* default to 1 */
+module_param(on_node, bool, 0644);
+MODULE_PARM_DESC(on_node, "Run threads only on NTB device node (default: true)");
+
 struct perf_mw {
        phys_addr_t     phys_addr;
        resource_size_t phys_size;
@@ -345,6 +349,10 @@ static int perf_move_data(struct pthr_ctx *pctx, char __iomem *dst, char *src,
 
 static bool perf_dma_filter_fn(struct dma_chan *chan, void *node)
 {
+       /* Is the channel required to be on the same node as the device? */
+       if (!on_node)
+               return true;
+
        return dev_to_node(&chan->dev->device) == (int)(unsigned long)node;
 }
 
@@ -362,7 +370,7 @@ static int ntb_perf_thread(void *data)
 
        pr_debug("kthread %s starting...\n", current->comm);
 
-       node = dev_to_node(&pdev->dev);
+       node = on_node ? dev_to_node(&pdev->dev) : NUMA_NO_NODE;
 
        if (use_dma && !pctx->dma_chan) {
                dma_cap_mask_t dma_mask;
@@ -682,7 +690,8 @@ static ssize_t debugfs_run_write(struct file *filp, const char __user *ubuf,
                pr_info("Fix run_order to %u\n", run_order);
        }
 
-       node = dev_to_node(&perf->ntb->pdev->dev);
+       node = on_node ? dev_to_node(&perf->ntb->pdev->dev)
+                      : NUMA_NO_NODE;
        atomic_set(&perf->tdone, 0);
 
        /* launch kernel thread */
@@ -779,8 +788,7 @@ static int perf_probe(struct ntb_client *client, struct ntb_dev *ntb)
        if (ntb_peer_port_count(ntb) != NTB_DEF_PEER_CNT)
                dev_warn(&ntb->dev, "Multi-port NTB devices unsupported\n");
 
-       node = dev_to_node(&pdev->dev);
-
+       node = on_node ? dev_to_node(&pdev->dev) : NUMA_NO_NODE;
        perf = kzalloc_node(sizeof(*perf), GFP_KERNEL, node);
        if (!perf) {
                rc = -ENOMEM;