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| author | Mike Christie <michael.christie@oracle.com> | 2023-09-28 05:09:05 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2023-10-13 22:53:58 +0300 |
| commit | e2f4ea40138e16d1dfd768f2dead8f3f75a85673 (patch) | |
| tree | 81462ae049d9d29cf8fac79e2468b21126695b59 /drivers/target/target_core_configfs.c | |
| parent | 428926796e7f3b2eb57b1d4886334d2f5abb35fa (diff) | |
| download | linux-e2f4ea40138e16d1dfd768f2dead8f3f75a85673.tar.xz | |
scsi: target: Allow userspace to request direct submissions
This allows userspace to request the fabric drivers do direct submissions
if they support it. With the new device file, submit_type, users can
write 0 - 2 to control how commands are submitted to the backend:
0 - TARGET_FABRIC_DEFAULT_SUBMIT - LIO will use the fabric's default
submission type. This is the default for compat.
1 - TARGET_DIRECT_SUBMIT - LIO will submit the cmd to the backend from the
calling context if the fabric the cmd was received on supports it,
else it will use the fabric's default type.
2 - TARGET_QUEUE_SUBMIT - LIO will queue the cmd to the LIO submission
workqueue which will pass it to the backend.
When using an NVMe drive and vhost-scsi with direct submission we see
around a 20% improvement in 4K I/Os:
fio jobs 1 2 4 8 10
--------------------------------------------------
defer 94K 190K 394K 770K 890K
direct 128K 252K 488K 950K -
And when using the queueing mode, we now no longer see issues like where
the iSCSI tx thread is blocked in the block layer waiting on a tag so it
can't respond to a nop or perform I/Os for other LUs.
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Link: https://lore.kernel.org/r/20230928020907.5730-6-michael.christie@oracle.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/target/target_core_configfs.c')
| -rw-r--r-- | drivers/target/target_core_configfs.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c index 936e5ff1b209..f7eaf17e9050 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(submit_type); #define DEF_CONFIGFS_ATTRIB_STORE_U32(_name) \ static ssize_t _name##_store(struct config_item *item, const char *page,\ @@ -1231,6 +1232,24 @@ static ssize_t emulate_rsoc_store(struct config_item *item, return count; } +static ssize_t submit_type_store(struct config_item *item, const char *page, + size_t count) +{ + struct se_dev_attrib *da = to_attrib(item); + int ret; + u8 val; + + ret = kstrtou8(page, 0, &val); + if (ret < 0) + return ret; + + if (val > TARGET_QUEUE_SUBMIT) + return -EINVAL; + + da->submit_type = val; + return count; +} + CONFIGFS_ATTR(, emulate_model_alias); CONFIGFS_ATTR(, emulate_dpo); CONFIGFS_ATTR(, emulate_fua_write); @@ -1266,6 +1285,7 @@ CONFIGFS_ATTR(, unmap_zeroes_data); CONFIGFS_ATTR(, max_write_same_len); CONFIGFS_ATTR(, alua_support); CONFIGFS_ATTR(, pgr_support); +CONFIGFS_ATTR(, submit_type); /* * dev_attrib attributes for devices using the target core SBC/SPC @@ -1308,6 +1328,7 @@ struct configfs_attribute *sbc_attrib_attrs[] = { &attr_alua_support, &attr_pgr_support, &attr_emulate_rsoc, + &attr_submit_type, NULL, }; EXPORT_SYMBOL(sbc_attrib_attrs); @@ -1325,6 +1346,7 @@ struct configfs_attribute *passthrough_attrib_attrs[] = { &attr_emulate_pr, &attr_alua_support, &attr_pgr_support, + &attr_submit_type, NULL, }; EXPORT_SYMBOL(passthrough_attrib_attrs); |