Drivers: hv: vmbus: Improve the CPU affiliation for channels

The current code tracks the assigned CPUs within a NUMA node in the context of
the primary channel. So, if we have a VM with a single NUMA node with 8 VCPUs, we may
end up unevenly distributing the channel load. Fix the issue by tracking affiliations
globally.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 30613df..39c5afc 100644 (file)
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -392,6 +392,7 @@ static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_gui
        struct vmbus_channel *primary = channel->primary_channel;
        int next_node;
        struct cpumask available_mask;
+       struct cpumask *alloced_mask;
 
        for (i = IDE; i < MAX_PERF_CHN; i++) {
                if (!memcmp(type_guid->b, hp_devs[i].guid,
@@ -409,7 +410,6 @@ static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_gui
                 * channel, bind it to cpu 0.
                 */
                channel->numa_node = 0;
-               cpumask_set_cpu(0, &channel->alloced_cpus_in_node);
                channel->target_cpu = 0;
                channel->target_vp = hv_context.vp_index[0];
                return;
@@ -434,21 +434,22 @@ static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_gui
                channel->numa_node = next_node;
                primary = channel;
        }
+       alloced_mask = &hv_context.hv_numa_map[primary->numa_node];
 
-       if (cpumask_weight(&primary->alloced_cpus_in_node) ==
+       if (cpumask_weight(alloced_mask) ==
            cpumask_weight(cpumask_of_node(primary->numa_node))) {
                /*
                 * We have cycled through all the CPUs in the node;
                 * reset the alloced map.
                 */
-               cpumask_clear(&primary->alloced_cpus_in_node);
+               cpumask_clear(alloced_mask);
        }
 
-       cpumask_xor(&available_mask, &primary->alloced_cpus_in_node,
+       cpumask_xor(&available_mask, alloced_mask,
                    cpumask_of_node(primary->numa_node));
 
        cur_cpu = cpumask_next(-1, &available_mask);
-       cpumask_set_cpu(cur_cpu, &primary->alloced_cpus_in_node);
+       cpumask_set_cpu(cur_cpu, alloced_mask);
 
        channel->target_cpu = cur_cpu;
        channel->target_vp = hv_context.vp_index[cur_cpu];

diff --cc drivers/hv/hv.c
Simple merge

diff --cc drivers/hv/hyperv_vmbus.h
Simple merge

diff --cc include/linux/hyperv.h
Simple merge