2022-05-17 01:20:46

by Pankaj Raghav

[permalink] [raw]
Subject: [PATCH v4 11/13] null_blk: allow non power of 2 zoned devices

Convert the power of 2 based calculation with zone size to be generic in
null_zone_no with optimization for power of 2 based zone sizes.

The nr_zones calculation in null_init_zoned_dev has been replaced with a
division without special handling for power of 2 based zone sizes as
this function is called only during the initialization and will not
invoked in the hot path.

Performance Measurement:

Device:
zone size = 128M, blocksize=4k

FIO cmd:

fio --name=zbc --filename=/dev/nullb0 --direct=1 --zonemode=zbd --size=23G
--io_size=<iosize> --ioengine=io_uring --iodepth=<iod> --rw=<mode> --bs=4k
--loops=4

The following results are an average of 4 runs on AMD Ryzen 5 5600X with
32GB of RAM:

Sequential Write:

x-----------------x---------------------------------x---------------------------------x
| IOdepth | 8 | 16 |
x-----------------x---------------------------------x---------------------------------x
| | KIOPS |BW(MiB/s) | Lat(usec) | KIOPS |BW(MiB/s) | Lat(usec) |
x-----------------x---------------------------------x---------------------------------x
| Without patch | 578 | 2257 | 12.80 | 576 | 2248 | 25.78 |
x-----------------x---------------------------------x---------------------------------x
| With patch | 581 | 2268 | 12.74 | 576 | 2248 | 25.85 |
x-----------------x---------------------------------x---------------------------------x

Sequential read:

x-----------------x---------------------------------x---------------------------------x
| IOdepth | 8 | 16 |
x-----------------x---------------------------------x---------------------------------x
| | KIOPS |BW(MiB/s) | Lat(usec) | KIOPS |BW(MiB/s) | Lat(usec) |
x-----------------x---------------------------------x---------------------------------x
| Without patch | 667 | 2605 | 11.79 | 675 | 2637 | 23.49 |
x-----------------x---------------------------------x---------------------------------x
| With patch | 667 | 2605 | 11.79 | 675 | 2638 | 23.48 |
x-----------------x---------------------------------x---------------------------------x

Random read:

x-----------------x---------------------------------x---------------------------------x
| IOdepth | 8 | 16 |
x-----------------x---------------------------------x---------------------------------x
| | KIOPS |BW(MiB/s) | Lat(usec) | KIOPS |BW(MiB/s) | Lat(usec) |
x-----------------x---------------------------------x---------------------------------x
| Without patch | 522 | 2038 | 15.05 | 514 | 2006 | 30.87 |
x-----------------x---------------------------------x---------------------------------x
| With patch | 522 | 2039 | 15.04 | 523 | 2042 | 30.33 |
x-----------------x---------------------------------x---------------------------------x

Minor variations are noticed in Sequential write with io depth 8 and
in random read with io depth 16. But overall no noticeable differences
were noticed

Reviewed-by: Luis Chamberlain <[email protected]>
Reviewed by: Adam Manzanares <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Signed-off-by: Pankaj Raghav <[email protected]>
---
drivers/block/null_blk/main.c | 5 ++---
drivers/block/null_blk/zoned.c | 14 +++++++-------
2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 5cb4c92cd..53557e014 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1929,9 +1929,8 @@ static int null_validate_conf(struct nullb_device *dev)
if (dev->queue_mode == NULL_Q_BIO)
dev->mbps = 0;

- if (dev->zoned &&
- (!dev->zone_size || !is_power_of_2(dev->zone_size))) {
- pr_err("zone_size must be power-of-two\n");
+ if (dev->zoned && !dev->zone_size) {
+ pr_err("Invalid zero zone size\n");
return -EINVAL;
}

diff --git a/drivers/block/null_blk/zoned.c b/drivers/block/null_blk/zoned.c
index dae54dd1a..00c34e65e 100644
--- a/drivers/block/null_blk/zoned.c
+++ b/drivers/block/null_blk/zoned.c
@@ -13,7 +13,10 @@ static inline sector_t mb_to_sects(unsigned long mb)

static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect)
{
- return sect >> ilog2(dev->zone_size_sects);
+ if (is_power_of_2(dev->zone_size_sects))
+ return sect >> ilog2(dev->zone_size_sects);
+
+ return div64_u64(sect, dev->zone_size_sects);
}

static inline void null_lock_zone_res(struct nullb_device *dev)
@@ -62,10 +65,6 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
sector_t sector = 0;
unsigned int i;

- if (!is_power_of_2(dev->zone_size)) {
- pr_err("zone_size must be power-of-two\n");
- return -EINVAL;
- }
if (dev->zone_size > dev->size) {
pr_err("Zone size larger than device capacity\n");
return -EINVAL;
@@ -83,8 +82,9 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
zone_capacity_sects = mb_to_sects(dev->zone_capacity);
dev_capacity_sects = mb_to_sects(dev->size);
dev->zone_size_sects = mb_to_sects(dev->zone_size);
- dev->nr_zones = round_up(dev_capacity_sects, dev->zone_size_sects)
- >> ilog2(dev->zone_size_sects);
+ dev->nr_zones =
+ div64_u64(roundup(dev_capacity_sects, dev->zone_size_sects),
+ dev->zone_size_sects);

dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct nullb_zone),
GFP_KERNEL | __GFP_ZERO);
--
2.25.1



2022-05-17 12:15:03

by kernel test robot

[permalink] [raw]
Subject: Re: [PATCH v4 11/13] null_blk: allow non power of 2 zoned devices

Hi Pankaj,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on next-20220516]
[also build test ERROR on v5.18-rc7]
[cannot apply to axboe-block/for-next kdave/for-next device-mapper-dm/for-next linus/master v5.18-rc7 v5.18-rc6 v5.18-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url: https://github.com/intel-lab-lkp/linux/commits/Pankaj-Raghav/block-make-blkdev_nr_zones-and-blk_queue_zone_no-generic-for-npo2-zsze/20220517-015435
base: 3f7bdc402fb06f897ff1f492a2d42e1f7c2efedb
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20220517/[email protected]/config)
compiler: m68k-linux-gcc (GCC) 11.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/1fc6f61076425c29e51cfa376f8dee4dbf588ed1
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Pankaj-Raghav/block-make-blkdev_nr_zones-and-blk_queue_zone_no-generic-for-npo2-zsze/20220517-015435
git checkout 1fc6f61076425c29e51cfa376f8dee4dbf588ed1
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>

All errors (new ones prefixed by >>):

m68k-linux-ld: drivers/block/null_blk/zoned.o: in function `null_init_zoned_dev':
>> zoned.c:(.text+0x9c6): undefined reference to `__udivdi3'
`.exit.text' referenced in section `.data' of sound/soc/codecs/tlv320adc3xxx.o: defined in discarded section `.exit.text' of sound/soc/codecs/tlv320adc3xxx.o

--
0-DAY CI Kernel Test Service
https://01.org/lkp