diff options
| author | Mike Christie <michael.christie@oracle.com> | 2021-02-27 20:00:04 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2021-03-05 01:37:02 +0300 |
| commit | 6888da8179fd4cfff4c6b62d5587ec2cd21e316d (patch) | |
| tree | ff67fca035a3fd731d5de969395626fc944b22b3 /drivers/target | |
| parent | 415ccd9811da38aed04f54051c8ae87699c4e6c2 (diff) | |
| download | linux-6888da8179fd4cfff4c6b62d5587ec2cd21e316d.tar.xz | |
scsi: target: tcmu: Add backend plug/unplug callouts
This patch adds plug/unplug callouts for tcmu, so we can avoid the number
of times we switch to userspace. Using this driver with tcm_loop is a
common config, and dependng on the nr_hw_queues (nr_hw_queues=1 performs
much better) and fio jobs (lower num jobs around 4) this patch can increase
IOPS by only around 5-10% because we hit other issues like the big per tcmu
device mutex.
Link: https://lore.kernel.org/r/20210227170006.5077-24-michael.christie@oracle.com
Reviewed-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/target')
| -rw-r--r-- | drivers/target/target_core_user.c | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index bf73cd5f4b04..48ccdf7e5bf8 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -111,6 +111,7 @@ struct tcmu_dev { struct kref kref; struct se_device se_dev; + struct se_dev_plug se_plug; char *name; struct se_hba *hba; @@ -119,6 +120,7 @@ struct tcmu_dev { #define TCMU_DEV_BIT_BROKEN 1 #define TCMU_DEV_BIT_BLOCKED 2 #define TCMU_DEV_BIT_TMR_NOTIFY 3 +#define TCM_DEV_BIT_PLUGGED 4 unsigned long flags; struct uio_info uio_info; @@ -959,6 +961,25 @@ static uint32_t ring_insert_padding(struct tcmu_dev *udev, size_t cmd_size) return cmd_head; } +static void tcmu_unplug_device(struct se_dev_plug *se_plug) +{ + struct se_device *se_dev = se_plug->se_dev; + struct tcmu_dev *udev = TCMU_DEV(se_dev); + + clear_bit(TCM_DEV_BIT_PLUGGED, &udev->flags); + uio_event_notify(&udev->uio_info); +} + +static struct se_dev_plug *tcmu_plug_device(struct se_device *se_dev) +{ + struct tcmu_dev *udev = TCMU_DEV(se_dev); + + if (!test_and_set_bit(TCM_DEV_BIT_PLUGGED, &udev->flags)) + return &udev->se_plug; + + return NULL; +} + /** * queue_cmd_ring - queue cmd to ring or internally * @tcmu_cmd: cmd to queue @@ -1086,8 +1107,8 @@ static int queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, sense_reason_t *scsi_err) list_add_tail(&tcmu_cmd->queue_entry, &udev->inflight_queue); - /* TODO: only if FLUSH and FUA? */ - uio_event_notify(&udev->uio_info); + if (!test_bit(TCM_DEV_BIT_PLUGGED, &udev->flags)) + uio_event_notify(&udev->uio_info); return 0; @@ -2863,6 +2884,8 @@ static struct target_backend_ops tcmu_ops = { .configure_device = tcmu_configure_device, .destroy_device = tcmu_destroy_device, .free_device = tcmu_free_device, + .unplug_device = tcmu_unplug_device, + .plug_device = tcmu_plug_device, .parse_cdb = tcmu_parse_cdb, .tmr_notify = tcmu_tmr_notify, .set_configfs_dev_params = tcmu_set_configfs_dev_params, |