From 8ef4c4abbbcdcd9d4bc0fd9454df03e6dac24b73 Mon Sep 17 00:00:00 2001 From: "Andrea Parri (Microsoft)" Date: Mon, 6 Apr 2020 02:15:11 +0200 Subject: Drivers: hv: vmbus: Remove the unused HV_LOCALIZED channel affinity logic The logic is unused since commit 509879bdb30b8 ("Drivers: hv: Introduce a policy for controlling channel affinity"). This logic assumes that a channel target_cpu doesn't change during the lifetime of a channel, but this assumption is incompatible with the new functionality that allows changing the vCPU a channel will interrupt. Signed-off-by: Andrea Parri (Microsoft) Link: https://lore.kernel.org/r/20200406001514.19876-9-parri.andrea@gmail.com Reviewed-by: Michael Kelley Signed-off-by: Wei Liu --- drivers/hv/channel_mgmt.c | 105 +++++++++++----------------------------------- 1 file changed, 25 insertions(+), 80 deletions(-) (limited to 'drivers/hv') diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index 2e730f84654b..a19dc28fdf77 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -433,14 +433,6 @@ void hv_process_channel_removal(struct vmbus_channel *channel) spin_unlock_irqrestore(&primary_channel->lock, flags); } - /* - * 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. - */ - if (channel->affinity_policy == HV_LOCALIZED) - cpumask_clear_cpu(channel->target_cpu, - &primary_channel->alloced_cpus_in_node); - /* * Upon suspend, an in-use hv_sock channel is marked as "rescinded" and * the relid is invalidated; after hibernation, when the user-space app @@ -662,20 +654,21 @@ static DEFINE_SPINLOCK(bind_channel_to_cpu_lock); /* * Starting with Win8, we can statically distribute the incoming * channel interrupt load by binding a channel to VCPU. - * We distribute the interrupt loads to one or more NUMA nodes based on - * the channel's affinity_policy. * * For pre-win8 hosts or non-performance critical channels we assign the * first CPU in the first NUMA node. + * + * Starting with win8, performance critical channels will be distributed + * evenly among all the available NUMA nodes. Once the node is assigned, + * we will assign the CPU based on a simple round robin scheme. */ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) { - u32 cur_cpu; bool perf_chn = vmbus_devs[dev_type].perf_device; - struct vmbus_channel *primary = channel->primary_channel; - int next_node; cpumask_var_t available_mask; struct cpumask *alloced_mask; + u32 target_cpu; + int numa_node; if ((vmbus_proto_version == VERSION_WS2008) || (vmbus_proto_version == VERSION_WIN7) || (!perf_chn) || @@ -693,31 +686,27 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) return; } - spin_lock(&bind_channel_to_cpu_lock); - /* - * Based on the channel affinity policy, we will assign the NUMA - * nodes. + * Serializes the accesses to the global variable next_numa_node_id. + * See also the header comment of the spin lock declaration. */ + spin_lock(&bind_channel_to_cpu_lock); - if ((channel->affinity_policy == HV_BALANCED) || (!primary)) { - while (true) { - next_node = next_numa_node_id++; - if (next_node == nr_node_ids) { - next_node = next_numa_node_id = 0; - continue; - } - if (cpumask_empty(cpumask_of_node(next_node))) - continue; - break; + while (true) { + numa_node = next_numa_node_id++; + if (numa_node == nr_node_ids) { + next_numa_node_id = 0; + continue; } - channel->numa_node = next_node; - primary = channel; + if (cpumask_empty(cpumask_of_node(numa_node))) + continue; + break; } - alloced_mask = &hv_context.hv_numa_map[primary->numa_node]; + channel->numa_node = numa_node; + alloced_mask = &hv_context.hv_numa_map[numa_node]; if (cpumask_weight(alloced_mask) == - cpumask_weight(cpumask_of_node(primary->numa_node))) { + cpumask_weight(cpumask_of_node(numa_node))) { /* * We have cycled through all the CPUs in the node; * reset the alloced map. @@ -725,57 +714,13 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) cpumask_clear(alloced_mask); } - cpumask_xor(available_mask, alloced_mask, - cpumask_of_node(primary->numa_node)); + cpumask_xor(available_mask, alloced_mask, cpumask_of_node(numa_node)); - cur_cpu = -1; - - 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); - if (cur_cpu >= nr_cpu_ids) { - cur_cpu = -1; - cpumask_copy(available_mask, - cpumask_of_node(primary->numa_node)); - continue; - } - - 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; - } - } + target_cpu = cpumask_first(available_mask); + cpumask_set_cpu(target_cpu, alloced_mask); - channel->target_cpu = cur_cpu; - channel->target_vp = hv_cpu_number_to_vp_number(cur_cpu); + channel->target_cpu = target_cpu; + channel->target_vp = hv_cpu_number_to_vp_number(target_cpu); spin_unlock(&bind_channel_to_cpu_lock); -- cgit v1.2.3-59-g8ed1b