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authorMike Christie <michael.christie@oracle.com>2021-02-27 20:00:04 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2021-03-05 01:37:02 +0300
commit6888da8179fd4cfff4c6b62d5587ec2cd21e316d (patch)
treeff67fca035a3fd731d5de969395626fc944b22b3 /drivers/target
parent415ccd9811da38aed04f54051c8ae87699c4e6c2 (diff)
downloadlinux-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.c27
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,