EXPORT_SYMBOL(dma_issue_pending_all);
/**
- * nth_chan - returns the nth channel of the given capability
+ * dma_chan_is_local - returns true if the channel is in the same numa-node as the cpu
+ */
+static bool dma_chan_is_local(struct dma_chan *chan, int cpu)
+{
+ int node = dev_to_node(chan->device->dev);
+ return node == -1 || cpumask_test_cpu(cpu, cpumask_of_node(node));
+}
+
+/**
+ * min_chan - returns the channel with min count and in the same numa-node as the cpu
* @cap: capability to match
- * @n: nth channel desired
+ * @cpu: cpu index which the channel should be close to
*
- * Defaults to returning the channel with the desired capability and the
- * lowest reference count when 'n' cannot be satisfied. Must be called
- * under dma_list_mutex.
+ * If some channels are close to the given cpu, the one with the lowest
+ * reference count is returned. Otherwise, cpu is ignored and only the
+ * reference count is taken into account.
+ * Must be called under dma_list_mutex.
*/
-static struct dma_chan *nth_chan(enum dma_transaction_type cap, int n)
+static struct dma_chan *min_chan(enum dma_transaction_type cap, int cpu)
{
struct dma_device *device;
struct dma_chan *chan;
- struct dma_chan *ret = NULL;
struct dma_chan *min = NULL;
+ struct dma_chan *localmin = NULL;
list_for_each_entry(device, &dma_device_list, global_node) {
if (!dma_has_cap(cap, device->cap_mask) ||
list_for_each_entry(chan, &device->channels, device_node) {
if (!chan->client_count)
continue;
- if (!min)
- min = chan;
- else if (chan->table_count < min->table_count)
+ if (!min || chan->table_count < min->table_count)
min = chan;
- if (n-- == 0) {
- ret = chan;
- break; /* done */
- }
+ if (dma_chan_is_local(chan, cpu))
+ if (!localmin ||
+ chan->table_count < localmin->table_count)
+ localmin = chan;
}
- if (ret)
- break; /* done */
}
- if (!ret)
- ret = min;
+ chan = localmin ? localmin : min;
- if (ret)
- ret->table_count++;
+ if (chan)
+ chan->table_count++;
- return ret;
+ return chan;
}
/**
struct dma_device *device;
int cpu;
int cap;
- int n;
/* undo the last distribution */
for_each_dma_cap_mask(cap, dma_cap_mask_all)
return;
/* redistribute available channels */
- n = 0;
for_each_dma_cap_mask(cap, dma_cap_mask_all)
for_each_online_cpu(cpu) {
- if (num_possible_cpus() > 1)
- chan = nth_chan(cap, n++);
- else
- chan = nth_chan(cap, -1);
-
+ chan = min_chan(cap, cpu);
per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
}
}