This patch adds a new module parameter to set the queue bounce limit.
Various queue limits parameters are usually present in the sysfs.
This is needed for testing purpose only so instead of poluting the
sysfs space just update the null_blk drivers.
This is needed especially for blktrace bounce related tracepoint
testing.
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
---
# modprobe null_blk bounce_pfn=0x1000
# for bs in 512 1024 2048 4096 8192
> do
> dd if=/dev/zero of=/dev/nullb0 bs=${bs} count=1 oflag=direct
> done
# ~/blktrace/blktrace -a write -d /dev/nullb0 -o -| ~/blktrace/blkparse -i -
#
# # With null_blk bounce
# modprobe null_blk bounce_pfn=0x1000
#
252,0 34 1 0.000000000 4390 Q WS 0 + 1 [dd]
252,0 34 2 0.000010139 4390 B WS 0 + 1 [dd]
252,0 34 3 0.000018996 4390 G WS 0 + 1 [dd]
252,0 34 4 0.000024576 4390 I WS 0 + 1 [dd]
252,0 34 5 0.000065152 829 D WS 0 + 1 [kworker/34:1H]
252,0 34 6 0.000092303 182 C WS 0 + 1 [0]
252,0 34 7 0.000098164 182 C WS 0 + 1 [0]
252,0 27 1 0.004573597 4391 Q WS 0 + 2 [dd]
252,0 27 2 0.004580891 4391 B WS 0 + 2 [dd]
252,0 27 3 0.004589687 4391 G WS 0 + 2 [dd]
252,0 27 4 0.004594356 4391 I WS 0 + 2 [dd]
252,0 27 5 0.004619473 1049 D WS 0 + 2 [kworker/27:1H]
252,0 27 6 0.004634411 147 C WS 0 + 2 [0]
252,0 27 7 0.004638609 147 C WS 0 + 2 [0]
252,0 29 1 0.014589610 4394 Q WS 0 + 8 [dd]
252,0 29 2 0.014595792 4394 B WS 0 + 8 [dd]
252,0 29 3 0.014599028 4394 G WS 0 + 8 [dd]
252,0 29 4 0.014601713 4394 I WS 0 + 8 [dd]
252,0 29 5 0.014621330 807 D WS 0 + 8 [kworker/29:1H]
252,0 29 6 0.014633813 157 C WS 0 + 8 [0]
252,0 29 7 0.014637660 157 C WS 0 + 8 [0]
252,0 30 1 0.009147174 4392 Q WS 0 + 4 [dd]
252,0 30 2 0.009154377 4392 B WS 0 + 4 [dd]
252,0 30 3 0.009163064 4392 G WS 0 + 4 [dd]
252,0 30 4 0.009167161 4392 I WS 0 + 4 [dd]
252,0 30 5 0.009191437 1084 D WS 0 + 4 [kworker/30:1H]
252,0 30 6 0.009206084 162 C WS 0 + 4 [0]
252,0 30 7 0.009210863 162 C WS 0 + 4 [0]
252,0 30 8 0.018510473 4395 Q WS 0 + 16 [dd]
252,0 30 9 0.018517767 4395 B WS 0 + 16 [dd]
252,0 30 10 0.018521213 4395 G WS 0 + 16 [dd]
252,0 30 11 0.018524229 4395 I WS 0 + 16 [dd]
252,0 30 12 0.018544026 1084 D WS 0 + 16 [kworker/30:1H]
252,0 30 13 0.018555127 162 C WS 0 + 16 [0]
252,0 30 14 0.018558333 162 C WS 0 + 16 [0]
# # Without null_blk bounce
252,0 38 1 0.000000000 4744 Q WS 0 + 1 [dd]
252,0 38 2 0.000014768 4744 G WS 0 + 1 [dd]
252,0 38 3 0.000021771 4744 I WS 0 + 1 [dd]
252,0 38 4 0.000062557 914 D WS 0 + 1 [kworker/38:1H]
252,0 38 5 0.000089768 202 C WS 0 + 1 [0]
252,0 32 1 0.018453947 4749 Q WS 0 + 16 [dd]
252,0 32 2 0.018466080 4749 G WS 0 + 16 [dd]
252,0 32 3 0.018470619 4749 I WS 0 + 16 [dd]
252,0 32 4 0.018495195 514 D WS 0 + 16 [kworker/32:1H]
252,0 32 5 0.018509942 172 C WS 0 + 16 [0]
252,0 55 1 0.005000087 4745 Q WS 0 + 2 [dd]
252,0 55 2 0.005005637 4745 G WS 0 + 2 [dd]
252,0 55 3 0.005008453 4745 I WS 0 + 2 [dd]
252,0 55 4 0.005029352 1082 D WS 0 + 2 [kworker/55:1H]
252,0 55 5 0.005041915 287 C WS 0 + 2 [0]
252,0 31 1 0.014158231 4748 Q WS 0 + 8 [dd]
252,0 31 2 0.014164173 4748 G WS 0 + 8 [dd]
252,0 31 3 0.014167308 4748 I WS 0 + 8 [dd]
252,0 31 4 0.014188759 1151 D WS 0 + 8 [kworker/31:1H]
252,0 31 5 0.014203015 167 C WS 0 + 8 [0]
252,0 58 1 0.010016655 4747 D WS 0 + 4 [systemd-udevd]
252,0 60 1 0.009982571 4746 Q WS 0 + 4 [dd]
252,0 60 2 0.009993942 4746 G WS 0 + 4 [dd]
252,0 60 3 0.009998661 4746 I WS 0 + 4 [dd]
252,0 60 4 0.010136269 0 C WS 0 + 4 [0]
---
drivers/block/null_blk/main.c | 20 +++++++++++++++++++-
drivers/block/null_blk/null_blk.h | 1 +
2 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 6e6cbb953a12..8ddf2ba961f7 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -156,6 +156,10 @@ static int g_max_sectors;
module_param_named(max_sectors, g_max_sectors, int, 0444);
MODULE_PARM_DESC(max_sectors, "Maximum size of a command (in 512B sectors)");
+static unsigned int g_bounce_pfn;
+module_param_named(bounce_pfn, g_bounce_pfn, int, 0444);
+MODULE_PARM_DESC(bounce_pfn, "Queue Bounce limit (default: 0)");
+
static unsigned int nr_devices = 1;
module_param(nr_devices, uint, 0444);
MODULE_PARM_DESC(nr_devices, "Number of devices to register");
@@ -354,6 +358,7 @@ NULLB_DEVICE_ATTR(submit_queues, uint, nullb_apply_submit_queues);
NULLB_DEVICE_ATTR(home_node, uint, NULL);
NULLB_DEVICE_ATTR(queue_mode, uint, NULL);
NULLB_DEVICE_ATTR(blocksize, uint, NULL);
+NULLB_DEVICE_ATTR(bounce_pfn, uint, NULL);
NULLB_DEVICE_ATTR(max_sectors, uint, NULL);
NULLB_DEVICE_ATTR(irqmode, uint, NULL);
NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL);
@@ -472,6 +477,7 @@ static struct configfs_attribute *nullb_device_attrs[] = {
&nullb_device_attr_home_node,
&nullb_device_attr_queue_mode,
&nullb_device_attr_blocksize,
+ &nullb_device_attr_bounce_pfn,
&nullb_device_attr_max_sectors,
&nullb_device_attr_irqmode,
&nullb_device_attr_hw_queue_depth,
@@ -543,7 +549,7 @@ nullb_group_drop_item(struct config_group *group, struct config_item *item)
static ssize_t memb_group_features_show(struct config_item *item, char *page)
{
return snprintf(page, PAGE_SIZE,
- "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size,zone_capacity,zone_nr_conv,zone_max_open,zone_max_active,blocksize,max_sectors\n");
+ "memory_backed,discard,bounce_pfn,bandwidth,cache,badblocks,zoned,zone_size,zone_capacity,zone_nr_conv\n");
}
CONFIGFS_ATTR_RO(memb_group_, features);
@@ -1610,6 +1616,17 @@ static void null_config_discard(struct nullb *nullb)
blk_queue_flag_set(QUEUE_FLAG_DISCARD, nullb->q);
}
+static void null_config_bounce_pfn(struct nullb *nullb)
+{
+ if (nullb->dev->memory_backed && nullb->dev->bounce_pfn == false)
+ return;
+
+ if (!nullb->dev->memory_backed && !g_bounce_pfn)
+ return;
+
+ blk_queue_bounce_limit(nullb->q, nullb->dev->bounce_pfn);
+}
+
static const struct block_device_operations null_bio_ops = {
.owner = THIS_MODULE,
.submit_bio = null_submit_bio,
@@ -1882,6 +1899,7 @@ static int null_add_dev(struct nullb_device *dev)
blk_queue_max_hw_sectors(nullb->q, dev->max_sectors);
null_config_discard(nullb);
+ null_config_bounce_pfn(nullb);
sprintf(nullb->disk_name, "nullb%d", nullb->index);
diff --git a/drivers/block/null_blk/null_blk.h b/drivers/block/null_blk/null_blk.h
index 83504f3cc9d6..cd55f99118bf 100644
--- a/drivers/block/null_blk/null_blk.h
+++ b/drivers/block/null_blk/null_blk.h
@@ -86,6 +86,7 @@ struct nullb_device {
unsigned int queue_mode; /* block interface */
unsigned int blocksize; /* block size */
unsigned int max_sectors; /* Max sectors per command */
+ unsigned int bounce_pfn; /* bounce page frame number */
unsigned int irqmode; /* IRQ completion handler */
unsigned int hw_queue_depth; /* queue depth */
unsigned int index; /* index of the disk, only valid with a disk */
--
2.22.1
