From d86adf482b843b3a58a9ec3b7c1ccdbf7c705db1 Mon Sep 17 00:00:00 2001 From: "K. Y. Srinivasan" Date: Wed, 14 Dec 2016 18:46:00 -0800 Subject: [PATCH] scsi: storvsc: Enable multi-queue support Enable multi-q support. We will allocate the outgoing channel using the following policy: 1. We will make every effort to pick a channel that is in the same NUMA node that is initiating the I/O 2. The mapping between the guest CPU and the outgoing channel is persistent. Signed-off-by: K. Y. Srinivasan Reviewed-by: Long Li Signed-off-by: Martin K. Petersen --- drivers/scsi/storvsc_drv.c | 113 ++++++++++++++++++++++++++++++++++++- 1 file changed, 110 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index 3b1c2f6528b4..63f6b1ad57c5 100644 --- a/drivers/scsi/storvsc_drv.c +++ b/drivers/scsi/storvsc_drv.c @@ -458,6 +458,15 @@ struct storvsc_device { * Max I/O, the device can support. */ u32 max_transfer_bytes; + /* + * Number of sub-channels we will open. + */ + u16 num_sc; + struct vmbus_channel **stor_chns; + /* + * Mask of CPUs bound to subchannels. + */ + struct cpumask alloced_cpus; /* Used for vsc/vsp channel reset process */ struct storvsc_cmd_request init_request; struct storvsc_cmd_request reset_request; @@ -635,6 +644,11 @@ static void handle_sc_creation(struct vmbus_channel *new_sc) (void *)&props, sizeof(struct vmstorage_channel_properties), storvsc_on_channel_callback, new_sc); + + if (new_sc->state == CHANNEL_OPENED_STATE) { + stor_device->stor_chns[new_sc->target_cpu] = new_sc; + cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus); + } } static void handle_multichannel_storage(struct hv_device *device, int max_chns) @@ -651,6 +665,7 @@ static void handle_multichannel_storage(struct hv_device *device, int max_chns) if (!stor_device) return; + stor_device->num_sc = num_sc; request = &stor_device->init_request; vstor_packet = &request->vstor_packet; @@ -838,6 +853,25 @@ static int storvsc_channel_init(struct hv_device *device, bool is_fc) * support multi-channel. */ max_chns = vstor_packet->storage_channel_properties.max_channel_cnt; + + /* + * Allocate state to manage the sub-channels. + * We allocate an array based on the numbers of possible CPUs + * (Hyper-V does not support cpu online/offline). + * This Array will be sparseley populated with unique + * channels - primary + sub-channels. + * We will however populate all the slots to evenly distribute + * the load. + */ + stor_device->stor_chns = kzalloc(sizeof(void *) * num_possible_cpus(), + GFP_KERNEL); + if (stor_device->stor_chns == NULL) + return -ENOMEM; + + stor_device->stor_chns[device->channel->target_cpu] = device->channel; + cpumask_set_cpu(device->channel->target_cpu, + &stor_device->alloced_cpus); + if (vmstor_proto_version >= VMSTOR_PROTO_VERSION_WIN8) { if (vstor_packet->storage_channel_properties.flags & STORAGE_CHANNEL_SUPPORTS_MULTI_CHANNEL) @@ -1198,17 +1232,64 @@ static int storvsc_dev_remove(struct hv_device *device) /* Close the channel */ vmbus_close(device->channel); + kfree(stor_device->stor_chns); kfree(stor_device); return 0; } +static struct vmbus_channel *get_og_chn(struct storvsc_device *stor_device, + u16 q_num) +{ + u16 slot = 0; + u16 hash_qnum; + struct cpumask alloced_mask; + int num_channels, tgt_cpu; + + if (stor_device->num_sc == 0) + return stor_device->device->channel; + + /* + * Our channel array is sparsley populated and we + * initiated I/O on a processor/hw-q that does not + * currently have a designated channel. Fix this. + * The strategy is simple: + * I. Ensure NUMA locality + * II. Distribute evenly (best effort) + * III. Mapping is persistent. + */ + + cpumask_and(&alloced_mask, &stor_device->alloced_cpus, + cpumask_of_node(cpu_to_node(q_num))); + + num_channels = cpumask_weight(&alloced_mask); + if (num_channels == 0) + return stor_device->device->channel; + + hash_qnum = q_num; + while (hash_qnum >= num_channels) + hash_qnum -= num_channels; + + for_each_cpu(tgt_cpu, &alloced_mask) { + if (slot == hash_qnum) + break; + slot++; + } + + stor_device->stor_chns[q_num] = stor_device->stor_chns[tgt_cpu]; + + return stor_device->stor_chns[q_num]; +} + + static int storvsc_do_io(struct hv_device *device, - struct storvsc_cmd_request *request) + struct storvsc_cmd_request *request, u16 q_num) { struct storvsc_device *stor_device; struct vstor_packet *vstor_packet; struct vmbus_channel *outgoing_channel; int ret = 0; + struct cpumask alloced_mask; + int tgt_cpu; vstor_packet = &request->vstor_packet; stor_device = get_out_stor_device(device); @@ -1222,7 +1303,26 @@ static int storvsc_do_io(struct hv_device *device, * Select an an appropriate channel to send the request out. */ - outgoing_channel = vmbus_get_outgoing_channel(device->channel); + if (stor_device->stor_chns[q_num] != NULL) { + outgoing_channel = stor_device->stor_chns[q_num]; + if (outgoing_channel->target_cpu == smp_processor_id()) { + /* + * Ideally, we want to pick a different channel if + * available on the same NUMA node. + */ + cpumask_and(&alloced_mask, &stor_device->alloced_cpus, + cpumask_of_node(cpu_to_node(q_num))); + for_each_cpu(tgt_cpu, &alloced_mask) { + if (tgt_cpu != outgoing_channel->target_cpu) { + outgoing_channel = + stor_device->stor_chns[tgt_cpu]; + break; + } + } + } + } else { + outgoing_channel = get_og_chn(stor_device, q_num); + } vstor_packet->flags |= REQUEST_COMPLETION_FLAG; @@ -1522,7 +1622,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) cmd_request->payload_sz = payload_sz; /* Invokes the vsc to start an IO */ - ret = storvsc_do_io(dev, cmd_request); + ret = storvsc_do_io(dev, cmd_request, get_cpu()); + put_cpu(); if (ret == -EAGAIN) { /* no more space */ @@ -1679,6 +1780,11 @@ static int storvsc_probe(struct hv_device *device, * from the host. */ host->sg_tablesize = (stor_device->max_transfer_bytes >> PAGE_SHIFT); + /* + * Set the number of HW queues we are supporting. + */ + if (stor_device->num_sc != 0) + host->nr_hw_queues = stor_device->num_sc + 1; /* Register the HBA and start the scsi bus scan */ ret = scsi_add_host(host, &device->device); @@ -1715,6 +1821,7 @@ err_out2: goto err_out0; err_out1: + kfree(stor_device->stor_chns); kfree(stor_device); err_out0: -- 2.20.1