This allows userspace to request the fabric drivers do direct submissions
if they support it.
When using a nvme drive and vhost-scsi we see around a 20% improvement
in 4K IOs:
fio jobs 1 2 4 8 10
--------------------------------------------------
defer 94K 190K 394K 770K 890K
direct 128K 252K 488K 950K -
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
---
drivers/target/loopback/tcm_loop.c | 2 +-
drivers/target/target_core_configfs.c | 5 ++++
drivers/target/target_core_device.c | 1 +
drivers/target/target_core_transport.c | 33 +++++++++++++++++++++++---
drivers/vhost/scsi.c | 2 +-
include/target/target_core_base.h | 5 ++++
6 files changed, 43 insertions(+), 5 deletions(-)
diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index 75804303b175..fbbf80ae9766 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -154,7 +154,7 @@ static void tcm_loop_target_queue_cmd(struct tcm_loop_cmd *tl_cmd)
GFP_ATOMIC))
return;
- target_queue_submission(se_cmd);
+ target_submit(se_cmd);
return;
out_done:
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 936e5ff1b209..e4ddd8882f83 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -577,6 +577,7 @@ DEF_CONFIGFS_ATTRIB_SHOW(unmap_granularity_alignment);
DEF_CONFIGFS_ATTRIB_SHOW(unmap_zeroes_data);
DEF_CONFIGFS_ATTRIB_SHOW(max_write_same_len);
DEF_CONFIGFS_ATTRIB_SHOW(emulate_rsoc);
+DEF_CONFIGFS_ATTRIB_SHOW(direct_submit);
#define DEF_CONFIGFS_ATTRIB_STORE_U32(_name) \
static ssize_t _name##_store(struct config_item *item, const char *page,\
@@ -598,6 +599,7 @@ DEF_CONFIGFS_ATTRIB_STORE_U32(max_unmap_block_desc_count);
DEF_CONFIGFS_ATTRIB_STORE_U32(unmap_granularity);
DEF_CONFIGFS_ATTRIB_STORE_U32(unmap_granularity_alignment);
DEF_CONFIGFS_ATTRIB_STORE_U32(max_write_same_len);
+DEF_CONFIGFS_ATTRIB_STORE_U32(direct_submit);
#define DEF_CONFIGFS_ATTRIB_STORE_BOOL(_name) \
static ssize_t _name##_store(struct config_item *item, const char *page, \
@@ -1266,6 +1268,7 @@ CONFIGFS_ATTR(, unmap_zeroes_data);
CONFIGFS_ATTR(, max_write_same_len);
CONFIGFS_ATTR(, alua_support);
CONFIGFS_ATTR(, pgr_support);
+CONFIGFS_ATTR(, direct_submit);
/*
* dev_attrib attributes for devices using the target core SBC/SPC
@@ -1308,6 +1311,7 @@ struct configfs_attribute *sbc_attrib_attrs[] = {
&attr_alua_support,
&attr_pgr_support,
&attr_emulate_rsoc,
+ &attr_direct_submit,
NULL,
};
EXPORT_SYMBOL(sbc_attrib_attrs);
@@ -1325,6 +1329,7 @@ struct configfs_attribute *passthrough_attrib_attrs[] = {
&attr_emulate_pr,
&attr_alua_support,
&attr_pgr_support,
+ &attr_direct_submit,
NULL,
};
EXPORT_SYMBOL(passthrough_attrib_attrs);
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index b7ac60f4a219..b4c3e17ebfc9 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -779,6 +779,7 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name)
dev->dev_attrib.unmap_zeroes_data =
DA_UNMAP_ZEROES_DATA_DEFAULT;
dev->dev_attrib.max_write_same_len = DA_MAX_WRITE_SAME_LEN;
+ dev->dev_attrib.direct_submit = DA_FABRIC_DEFAULT_SUBMIT;
xcopy_lun = &dev->xcopy_lun;
rcu_assign_pointer(xcopy_lun->lun_se_dev, dev);
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 687adc9e086c..5349a2dd8187 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1781,13 +1781,13 @@ int target_submit_prep(struct se_cmd *se_cmd, unsigned char *cdb,
EXPORT_SYMBOL_GPL(target_submit_prep);
/**
- * target_submit - perform final initialization and submit cmd to LIO core
+ * __target_submit - perform final initialization and submit cmd to LIO core
* @se_cmd: command descriptor to submit
*
* target_submit_prep must have been called on the cmd, and this must be
* called from process context.
*/
-void target_submit(struct se_cmd *se_cmd)
+static void __target_submit(struct se_cmd *se_cmd)
{
struct scatterlist *sgl = se_cmd->t_data_sg;
unsigned char *buf = NULL;
@@ -1825,6 +1825,33 @@ void target_submit(struct se_cmd *se_cmd)
transport_handle_cdb_direct(se_cmd);
}
+
+/**
+ * target_submit - submit cmd to LIO core or queue it's submission
+ * @se_cmd: command descriptor to submit
+ */
+void target_submit(struct se_cmd *se_cmd)
+{
+ struct se_dev_attrib *da = &se_cmd->se_dev->dev_attrib;
+ u32 direct_submit;
+
+ if (da->direct_submit == DA_FABRIC_DEFAULT_SUBMIT) {
+ if (se_cmd->se_sess->se_tpg->se_tpg_tfo->default_direct_submit)
+ direct_submit = DA_DIRECT_SUBMIT;
+ else
+ direct_submit = DA_QUEUE_SUBMIT;
+ } else if (da->direct_submit == DA_DIRECT_SUBMIT &&
+ se_cmd->se_sess->se_tpg->se_tpg_tfo->direct_submit_supp) {
+ direct_submit = DA_DIRECT_SUBMIT;
+ } else {
+ direct_submit = DA_QUEUE_SUBMIT;
+ }
+
+ if (direct_submit == DA_DIRECT_SUBMIT)
+ __target_submit(se_cmd);
+ else
+ target_queue_submission(se_cmd);
+}
EXPORT_SYMBOL_GPL(target_submit);
/**
@@ -1922,7 +1949,7 @@ void target_queued_submit_work(struct work_struct *work)
se_plug = target_plug_device(se_dev);
}
- target_submit(se_cmd);
+ __target_submit(se_cmd);
}
if (se_plug)
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index ed6cc84c0b85..e2603eb1b638 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -772,7 +772,7 @@ static void vhost_scsi_target_queue_cmd(struct vhost_scsi_cmd *cmd)
cmd->tvc_prot_sgl_count, GFP_KERNEL))
return;
- target_queue_submission(se_cmd);
+ target_submit(se_cmd);
}
static void
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 159567359bbb..4f37324ada5d 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -103,6 +103,10 @@
#define DA_IS_NONROT 0
/* Queue Algorithm Modifier default for restricted reordering in control mode page */
#define DA_EMULATE_REST_REORD 0
+/* Command submission settings */
+#define DA_FABRIC_DEFAULT_SUBMIT 0
+#define DA_DIRECT_SUBMIT 1
+#define DA_QUEUE_SUBMIT 2
#define SE_INQUIRY_BUF 1024
#define SE_MODE_PAGE_BUF 512
@@ -717,6 +721,7 @@ struct se_dev_attrib {
u32 unmap_granularity;
u32 unmap_granularity_alignment;
u32 max_write_same_len;
+ u32 direct_submit;
struct se_device *da_dev;
struct config_group da_group;
};
--
2.34.1
