From 509879bdb30b8e12bd0b3cb0bc8429f01478df4b Mon Sep 17 00:00:00 2001 From: "K. Y. Srinivasan" Date: Fri, 2 Sep 2016 05:58:23 -0700 Subject: [PATCH] Drivers: hv: Introduce a policy for controlling channel affinity Introduce a mechanism to control how channels will be affinitized. We will support two policies: 1. HV_BALANCED: All performance critical channels will be dstributed evenly amongst all the available NUMA nodes. Once the Node is assigned, we will assign the CPU based on a simple round robin scheme. 2. HV_LOCALIZED: Only the primary channels are distributed across all NUMA nodes. Sub-channels will be in the same NUMA node as the primary channel. This is the current behaviour. The default policy will be the HV_BALANCED as it can minimize the remote memory access on NUMA machines with applications that span NUMA nodes. Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/channel_mgmt.c | 68 ++++++++++++++++++++++----------------- include/linux/hyperv.h | 23 +++++++++++++ 2 files changed, 62 insertions(+), 29 deletions(-) diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index d8b64ba45b1d..bbd812e87511 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -356,8 +356,9 @@ void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid) * We need to free the bit for init_vp_index() to work in the case * of sub-channel, when we reload drivers like hv_netvsc. */ - cpumask_clear_cpu(channel->target_cpu, - &primary_channel->alloced_cpus_in_node); + if (channel->affinity_policy == HV_LOCALIZED) + cpumask_clear_cpu(channel->target_cpu, + &primary_channel->alloced_cpus_in_node); vmbus_release_relid(relid); @@ -548,17 +549,17 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) } /* - * We distribute primary channels evenly across all the available - * NUMA nodes and within the assigned NUMA node we will assign the - * first available CPU to the primary channel. - * The sub-channels will be assigned to the CPUs available in the - * NUMA node evenly. + * Based on the channel affinity policy, we will assign the NUMA + * nodes. */ - if (!primary) { + + if ((channel->affinity_policy == HV_BALANCED) || (!primary)) { while (true) { next_node = next_numa_node_id++; - if (next_node == nr_node_ids) + if (next_node == nr_node_ids) { next_node = next_numa_node_id = 0; + continue; + } if (cpumask_empty(cpumask_of_node(next_node))) continue; break; @@ -582,15 +583,17 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) cur_cpu = -1; - /* - * Normally Hyper-V host doesn't create more subchannels than there - * are VCPUs on the node but it is possible when not all present VCPUs - * on the node are initialized by guest. Clear the alloced_cpus_in_node - * to start over. - */ - if (cpumask_equal(&primary->alloced_cpus_in_node, - cpumask_of_node(primary->numa_node))) - cpumask_clear(&primary->alloced_cpus_in_node); + if (primary->affinity_policy == HV_LOCALIZED) { + /* + * Normally Hyper-V host doesn't create more subchannels + * than there are VCPUs on the node but it is possible when not + * all present VCPUs on the node are initialized by guest. + * Clear the alloced_cpus_in_node to start over. + */ + if (cpumask_equal(&primary->alloced_cpus_in_node, + cpumask_of_node(primary->numa_node))) + cpumask_clear(&primary->alloced_cpus_in_node); + } while (true) { cur_cpu = cpumask_next(cur_cpu, &available_mask); @@ -601,17 +604,24 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) continue; } - /* - * NOTE: in the case of sub-channel, we clear the sub-channel - * related bit(s) in primary->alloced_cpus_in_node in - * hv_process_channel_removal(), so when we reload drivers - * like hv_netvsc in SMP guest, here we're able to re-allocate - * bit from primary->alloced_cpus_in_node. - */ - if (!cpumask_test_cpu(cur_cpu, - &primary->alloced_cpus_in_node)) { - cpumask_set_cpu(cur_cpu, - &primary->alloced_cpus_in_node); + if (primary->affinity_policy == HV_LOCALIZED) { + /* + * NOTE: in the case of sub-channel, we clear the + * sub-channel related bit(s) in + * primary->alloced_cpus_in_node in + * hv_process_channel_removal(), so when we + * reload drivers like hv_netvsc in SMP guest, here + * we're able to re-allocate + * bit from primary->alloced_cpus_in_node. + */ + if (!cpumask_test_cpu(cur_cpu, + &primary->alloced_cpus_in_node)) { + cpumask_set_cpu(cur_cpu, + &primary->alloced_cpus_in_node); + cpumask_set_cpu(cur_cpu, alloced_mask); + break; + } + } else { cpumask_set_cpu(cur_cpu, alloced_mask); break; } diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index e6ef571e6100..c877e7980585 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -674,6 +674,11 @@ enum hv_signal_policy { HV_SIGNAL_POLICY_EXPLICIT, }; +enum hv_numa_policy { + HV_BALANCED = 0, + HV_LOCALIZED, +}; + enum vmbus_device_type { HV_IDE = 0, HV_SCSI, @@ -876,6 +881,18 @@ struct vmbus_channel { */ bool low_latency; + /* + * NUMA distribution policy: + * We support teo policies: + * 1) Balanced: Here all performance critical channels are + * distributed evenly amongst all the NUMA nodes. + * This policy will be the default policy. + * 2) Localized: All channels of a given instance of a + * performance critical service will be assigned CPUs + * within a selected NUMA node. + */ + enum hv_numa_policy affinity_policy; + }; static inline void set_channel_lock_state(struct vmbus_channel *c, bool state) @@ -895,6 +912,12 @@ static inline void set_channel_signal_state(struct vmbus_channel *c, c->signal_policy = policy; } +static inline void set_channel_affinity_state(struct vmbus_channel *c, + enum hv_numa_policy policy) +{ + c->affinity_policy = policy; +} + static inline void set_channel_read_state(struct vmbus_channel *c, bool state) { c->batched_reading = state; -- 2.39.5