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authorAsias He <asias@redhat.com>2013-02-06 13:20:59 +0800
committerNicholas Bellinger <nab@linux-iscsi.org>2013-02-13 11:30:14 -0800
commit1b7f390eb3bfc197c979c5478eadbc2a90f07667 (patch)
tree969efecaf717e4d94b55eaaa5a3fc2f678956459 /drivers/vhost
parent67e18cf9ab21648a477e91e0d3cb6dbdb1330262 (diff)
downloadlinux-1b7f390eb3bfc197c979c5478eadbc2a90f07667.tar.bz2
tcm_vhost: Multi-queue support
This adds virtio-scsi multi-queue support to tcm_vhost. In order to use multi-queue, guest side multi-queue support is need. It can be found here: https://lkml.org/lkml/2012/12/18/166 Currently, only one thread is created by vhost core code for each vhost_scsi instance. Even if there are multi-queues, all the handling of guest kick (vhost_scsi_handle_kick) are processed in one thread. This is not optimal. Luckily, most of the work is offloaded to the tcm_vhost workqueue. Some initial perf numbers: 1 queue, 4 targets, 1 lun per target 4K request size, 50% randread + 50% randwrite: 127K/127k IOPS 4 queues, 4 targets, 1 lun per target 4K request size, 50% randread + 50% randwrite: 181K/181k IOPS Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/vhost')
-rw-r--r--drivers/vhost/tcm_vhost.c46
-rw-r--r--drivers/vhost/tcm_vhost.h2
2 files changed, 31 insertions, 17 deletions
diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index 81ecda54b923..9951297b2427 100644
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -48,6 +48,7 @@
#include <linux/virtio_net.h> /* TODO vhost.h currently depends on this */
#include <linux/virtio_scsi.h>
#include <linux/llist.h>
+#include <linux/bitmap.h>
#include "vhost.c"
#include "vhost.h"
@@ -59,7 +60,8 @@ enum {
VHOST_SCSI_VQ_IO = 2,
};
-#define VHOST_SCSI_MAX_TARGET 256
+#define VHOST_SCSI_MAX_TARGET 256
+#define VHOST_SCSI_MAX_VQ 128
struct vhost_scsi {
/* Protected by vhost_scsi->dev.mutex */
@@ -68,7 +70,7 @@ struct vhost_scsi {
bool vs_endpoint;
struct vhost_dev dev;
- struct vhost_virtqueue vqs[3];
+ struct vhost_virtqueue vqs[VHOST_SCSI_MAX_VQ];
struct vhost_work vs_completion_work; /* cmd completion work item */
struct llist_head vs_completion_list; /* cmd completion queue */
@@ -366,12 +368,14 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
{
struct vhost_scsi *vs = container_of(work, struct vhost_scsi,
vs_completion_work);
+ DECLARE_BITMAP(signal, VHOST_SCSI_MAX_VQ);
struct virtio_scsi_cmd_resp v_rsp;
struct tcm_vhost_cmd *tv_cmd;
struct llist_node *llnode;
struct se_cmd *se_cmd;
- int ret;
+ int ret, vq;
+ bitmap_zero(signal, VHOST_SCSI_MAX_VQ);
llnode = llist_del_all(&vs->vs_completion_list);
while (llnode) {
tv_cmd = llist_entry(llnode, struct tcm_vhost_cmd,
@@ -390,15 +394,20 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
memcpy(v_rsp.sense, tv_cmd->tvc_sense_buf,
v_rsp.sense_len);
ret = copy_to_user(tv_cmd->tvc_resp, &v_rsp, sizeof(v_rsp));
- if (likely(ret == 0))
- vhost_add_used(&vs->vqs[2], tv_cmd->tvc_vq_desc, 0);
- else
+ if (likely(ret == 0)) {
+ vhost_add_used(tv_cmd->tvc_vq, tv_cmd->tvc_vq_desc, 0);
+ vq = tv_cmd->tvc_vq - vs->vqs;
+ __set_bit(vq, signal);
+ } else
pr_err("Faulted on virtio_scsi_cmd_resp\n");
vhost_scsi_free_cmd(tv_cmd);
}
- vhost_signal(&vs->dev, &vs->vqs[2]);
+ vq = -1;
+ while ((vq = find_next_bit(signal, VHOST_SCSI_MAX_VQ, vq + 1))
+ < VHOST_SCSI_MAX_VQ)
+ vhost_signal(&vs->dev, &vs->vqs[vq]);
}
static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd(
@@ -561,9 +570,9 @@ static void tcm_vhost_submission_work(struct work_struct *work)
}
}
-static void vhost_scsi_handle_vq(struct vhost_scsi *vs)
+static void vhost_scsi_handle_vq(struct vhost_scsi *vs,
+ struct vhost_virtqueue *vq)
{
- struct vhost_virtqueue *vq = &vs->vqs[2];
struct virtio_scsi_cmd_req v_req;
struct tcm_vhost_tpg *tv_tpg;
struct tcm_vhost_cmd *tv_cmd;
@@ -656,7 +665,7 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs)
ret = __copy_to_user(resp, &rsp, sizeof(rsp));
if (!ret)
vhost_add_used_and_signal(&vs->dev,
- &vs->vqs[2], head, 0);
+ vq, head, 0);
else
pr_err("Faulted on virtio_scsi_cmd_resp\n");
@@ -678,6 +687,7 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs)
": %d\n", tv_cmd, exp_data_len, data_direction);
tv_cmd->tvc_vhost = vs;
+ tv_cmd->tvc_vq = vq;
if (unlikely(vq->iov[out].iov_len !=
sizeof(struct virtio_scsi_cmd_resp))) {
@@ -758,7 +768,7 @@ static void vhost_scsi_handle_kick(struct vhost_work *work)
poll.work);
struct vhost_scsi *vs = container_of(vq->dev, struct vhost_scsi, dev);
- vhost_scsi_handle_vq(vs);
+ vhost_scsi_handle_vq(vs, vq);
}
/*
@@ -879,7 +889,7 @@ err:
static int vhost_scsi_open(struct inode *inode, struct file *f)
{
struct vhost_scsi *s;
- int r;
+ int r, i;
s = kzalloc(sizeof(*s), GFP_KERNEL);
if (!s)
@@ -889,8 +899,9 @@ static int vhost_scsi_open(struct inode *inode, struct file *f)
s->vqs[VHOST_SCSI_VQ_CTL].handle_kick = vhost_scsi_ctl_handle_kick;
s->vqs[VHOST_SCSI_VQ_EVT].handle_kick = vhost_scsi_evt_handle_kick;
- s->vqs[VHOST_SCSI_VQ_IO].handle_kick = vhost_scsi_handle_kick;
- r = vhost_dev_init(&s->dev, s->vqs, 3);
+ for (i = VHOST_SCSI_VQ_IO; i < VHOST_SCSI_MAX_VQ; i++)
+ s->vqs[i].handle_kick = vhost_scsi_handle_kick;
+ r = vhost_dev_init(&s->dev, s->vqs, VHOST_SCSI_MAX_VQ);
if (r < 0) {
kfree(s);
return r;
@@ -922,9 +933,10 @@ static void vhost_scsi_flush_vq(struct vhost_scsi *vs, int index)
static void vhost_scsi_flush(struct vhost_scsi *vs)
{
- vhost_scsi_flush_vq(vs, VHOST_SCSI_VQ_CTL);
- vhost_scsi_flush_vq(vs, VHOST_SCSI_VQ_EVT);
- vhost_scsi_flush_vq(vs, VHOST_SCSI_VQ_IO);
+ int i;
+
+ for (i = 0; i < VHOST_SCSI_MAX_VQ; i++)
+ vhost_scsi_flush_vq(vs, i);
}
static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features)
diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h
index 519a5504d347..1d2ae7a60e11 100644
--- a/drivers/vhost/tcm_vhost.h
+++ b/drivers/vhost/tcm_vhost.h
@@ -23,6 +23,8 @@ struct tcm_vhost_cmd {
struct virtio_scsi_cmd_resp __user *tvc_resp;
/* Pointer to vhost_scsi for our device */
struct vhost_scsi *tvc_vhost;
+ /* Pointer to vhost_virtqueue for the cmd */
+ struct vhost_virtqueue *tvc_vq;
/* Pointer to vhost nexus memory */
struct tcm_vhost_nexus *tvc_nexus;
/* The TCM I/O descriptor that is accessed via container_of() */