[dm-devel] [PATCH 10/12] dm-zoned: support arbitrary number of devices
Damien Le Moal
Damien.LeMoal at wdc.com
Mon May 25 08:22:55 UTC 2020
On 2020/05/25 16:52, Hannes Reinecke wrote:
> On 5/25/20 4:36 AM, Damien Le Moal wrote:
>> On 2020/05/23 0:39, Hannes Reinecke wrote:
>>> Remove the hard-coded limit of two devices and support an unlimited
>>> number of additional zoned devices.
>>> With that we need to increase the device-mapper version number to
>>> 3.0.0 as we've modified the interface.
>>>
>>> Signed-off-by: Hannes Reinecke <hare at suse.de>
>>> ---
>>> drivers/md/dm-zoned-metadata.c | 68 +++++++++++-----------
>>> drivers/md/dm-zoned-reclaim.c | 28 ++++++---
>>> drivers/md/dm-zoned-target.c | 129 +++++++++++++++++++++++++----------------
>>> drivers/md/dm-zoned.h | 9 +--
>>> 4 files changed, 139 insertions(+), 95 deletions(-)
>>>
>>> diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
>>> index 5f44970a6187..87784e7785bc 100644
>>> --- a/drivers/md/dm-zoned-metadata.c
>>> +++ b/drivers/md/dm-zoned-metadata.c
>>> @@ -260,6 +260,11 @@ unsigned int dmz_zone_nr_sectors_shift(struct dmz_metadata *zmd)
>>> return zmd->zone_nr_sectors_shift;
>>> }
>>>
>>> +unsigned int dmz_nr_devs(struct dmz_metadata *zmd)
>>> +{
>>> + return zmd->nr_devs;
>>> +}
>>
>> Is this helper really needed ?
>>
>
> Yes, in dm-zoned-reclaim.c
I meant to say: whoever needs to know the number of devices can just use
"zmd->nr_devs". No need for a helper for that was my point.
>
>>> +
>>> unsigned int dmz_nr_zones(struct dmz_metadata *zmd)
>>> {
>>> return zmd->nr_zones;
>>> @@ -270,24 +275,14 @@ unsigned int dmz_nr_chunks(struct dmz_metadata *zmd)
>>> return zmd->nr_chunks;
>>> }
>>>
>>> -unsigned int dmz_nr_rnd_zones(struct dmz_metadata *zmd)
>>> +unsigned int dmz_nr_rnd_zones(struct dmz_metadata *zmd, int idx)
>>> {
>>> - unsigned int nr_rnd_zones = 0;
>>> - int i;
>>> -
>>> - for (i = 0; i < zmd->nr_devs; i++)
>>> - nr_rnd_zones += zmd->dev[i].nr_rnd;
>>> - return nr_rnd_zones;
>>> + return zmd->dev[idx].nr_rnd;
>>
>> AH. OK. So my comment on patch 8 is voided :)
>>
> Yeah, the patch arrangement could be improved; I'll see to roll both
> changes into one patch.
>
>>> }
>>>
>>> -unsigned int dmz_nr_unmap_rnd_zones(struct dmz_metadata *zmd)
>>> +unsigned int dmz_nr_unmap_rnd_zones(struct dmz_metadata *zmd, int idx)
>>> {
>>> - unsigned int nr_unmap_rnd_zones = 0;
>>> - int i;
>>> -
>>> - for (i = 0; i < zmd->nr_devs; i++)
>>> - nr_unmap_rnd_zones += atomic_read(&zmd->dev[i].unmap_nr_rnd);
>>> - return nr_unmap_rnd_zones;
>>> + return atomic_read(&zmd->dev[idx].unmap_nr_rnd);
>>> }
>>>
>>> unsigned int dmz_nr_cache_zones(struct dmz_metadata *zmd)
>>> @@ -300,24 +295,14 @@ unsigned int dmz_nr_unmap_cache_zones(struct dmz_metadata *zmd)
>>> return atomic_read(&zmd->unmap_nr_cache);
>>> }
>>>
>>> -unsigned int dmz_nr_seq_zones(struct dmz_metadata *zmd)
>>> +unsigned int dmz_nr_seq_zones(struct dmz_metadata *zmd, int idx)
>>> {
>>> - unsigned int nr_seq_zones = 0;
>>> - int i;
>>> -
>>> - for (i = 0; i < zmd->nr_devs; i++)
>>> - nr_seq_zones += zmd->dev[i].nr_seq;
>>> - return nr_seq_zones;
>>> + return zmd->dev[idx].nr_seq;
>>> }
>>>
>>> -unsigned int dmz_nr_unmap_seq_zones(struct dmz_metadata *zmd)
>>> +unsigned int dmz_nr_unmap_seq_zones(struct dmz_metadata *zmd, int idx)
>>> {
>>> - unsigned int nr_unmap_seq_zones = 0;
>>> - int i;
>>> -
>>> - for (i = 0; i < zmd->nr_devs; i++)
>>> - nr_unmap_seq_zones += atomic_read(&zmd->dev[i].unmap_nr_seq);
>>> - return nr_unmap_seq_zones;
>>> + return atomic_read(&zmd->dev[idx].unmap_nr_seq);
>>> }
>>>
>>> static struct dm_zone *dmz_get(struct dmz_metadata *zmd, unsigned int zone_id)
>>> @@ -1530,7 +1515,20 @@ static int dmz_init_zones(struct dmz_metadata *zmd)
>>> */
>>> zmd->sb[0].zone = dmz_get(zmd, 0);
>>>
>>> - zoned_dev = &zmd->dev[1];
>>> + for (i = 1; i < zmd->nr_devs; i++) {
>>> + zoned_dev = &zmd->dev[i];
>>> +
>>> + ret = blkdev_report_zones(zoned_dev->bdev, 0,
>>> + BLK_ALL_ZONES,
>>> + dmz_init_zone, zoned_dev);
>>> + if (ret < 0) {
>>> + DMDEBUG("(%s): Failed to report zones, error %d",
>>> + zmd->devname, ret);
>>> + dmz_drop_zones(zmd);
>>> + return ret;
>>> + }
>>> + }
>>> + return 0;
>>> }
>>>
>>> /*
>>> @@ -2921,10 +2919,14 @@ int dmz_ctr_metadata(struct dmz_dev *dev, int num_dev,
>>> zmd->nr_data_zones, zmd->nr_chunks);
>>> dmz_zmd_debug(zmd, " %u cache zones (%u unmapped)",
>>> zmd->nr_cache, atomic_read(&zmd->unmap_nr_cache));
>>> - dmz_zmd_debug(zmd, " %u random zones (%u unmapped)",
>>> - dmz_nr_rnd_zones(zmd), dmz_nr_unmap_rnd_zones(zmd));
>>> - dmz_zmd_debug(zmd, " %u sequential zones (%u unmapped)",
>>> - dmz_nr_seq_zones(zmd), dmz_nr_unmap_seq_zones(zmd));
>>> + for (i = 0; i < zmd->nr_devs; i++) {
>>> + dmz_zmd_debug(zmd, " %u random zones (%u unmapped)",
>>> + dmz_nr_rnd_zones(zmd, i),
>>> + dmz_nr_unmap_rnd_zones(zmd, i));
>>> + dmz_zmd_debug(zmd, " %u sequential zones (%u unmapped)",
>>> + dmz_nr_seq_zones(zmd, i),
>>> + dmz_nr_unmap_seq_zones(zmd, i));
>>> + }
>>> dmz_zmd_debug(zmd, " %u reserved sequential data zones",
>>> zmd->nr_reserved_seq);
>>> dmz_zmd_debug(zmd, "Format:");
>>> diff --git a/drivers/md/dm-zoned-reclaim.c b/drivers/md/dm-zoned-reclaim.c
>>> index fba0d48e38a7..f2e053b5f2db 100644
>>> --- a/drivers/md/dm-zoned-reclaim.c
>>> +++ b/drivers/md/dm-zoned-reclaim.c
>>> @@ -442,15 +442,18 @@ static unsigned int dmz_reclaim_percentage(struct dmz_reclaim *zrc)
>>> {
>>> struct dmz_metadata *zmd = zrc->metadata;
>>> unsigned int nr_cache = dmz_nr_cache_zones(zmd);
>>> - unsigned int nr_rnd = dmz_nr_rnd_zones(zmd);
>>> - unsigned int nr_unmap, nr_zones;
>>> + unsigned int nr_unmap = 0, nr_zones = 0;
>>>
>>> if (nr_cache) {
>>> nr_zones = nr_cache;
>>> nr_unmap = dmz_nr_unmap_cache_zones(zmd);
>>> } else {
>>> - nr_zones = nr_rnd;
>>> - nr_unmap = dmz_nr_unmap_rnd_zones(zmd);
>>> + int i;
>>> +
>>> + for (i = 0; i < dmz_nr_devs(zmd); i++) {
>>> + nr_zones += dmz_nr_rnd_zones(zmd, i);
>>
>> May be not... We could keep constant totals in zmd to avoid this.
>>
>>> + nr_unmap += dmz_nr_unmap_rnd_zones(zmd, i);
>>> + }
>>> }
>>> return nr_unmap * 100 / nr_zones;
>>> }
>>> @@ -460,7 +463,11 @@ static unsigned int dmz_reclaim_percentage(struct dmz_reclaim *zrc)
>>> */
>>> static bool dmz_should_reclaim(struct dmz_reclaim *zrc, unsigned int p_unmap)
>>> {
>>> - unsigned int nr_reclaim = dmz_nr_rnd_zones(zrc->metadata);
>>> + int i;
>>> + unsigned int nr_reclaim = 0;
>>> +
>>> + for (i = 0; i < dmz_nr_devs(zrc->metadata); i++)
>>> + nr_reclaim += dmz_nr_rnd_zones(zrc->metadata, i);
>>>
>>> if (dmz_nr_cache_zones(zrc->metadata))
>>> nr_reclaim += dmz_nr_cache_zones(zrc->metadata);
>>> @@ -487,8 +494,8 @@ static void dmz_reclaim_work(struct work_struct *work)
>>> {
>>> struct dmz_reclaim *zrc = container_of(work, struct dmz_reclaim, work.work);
>>> struct dmz_metadata *zmd = zrc->metadata;
>>> - unsigned int p_unmap;
>>> - int ret;
>>> + unsigned int p_unmap, nr_unmap_rnd = 0, nr_rnd = 0;
>>> + int ret, i;
>>>
>>> if (dmz_dev_is_dying(zmd))
>>> return;
>>> @@ -513,14 +520,17 @@ static void dmz_reclaim_work(struct work_struct *work)
>>> zrc->kc_throttle.throttle = min(75U, 100U - p_unmap / 2);
>>> }
>>>
>>> + for (i = 0; i < dmz_nr_devs(zmd); i++) {
>>> + nr_unmap_rnd += dmz_nr_unmap_rnd_zones(zmd, i);
>>> + nr_rnd += dmz_nr_rnd_zones(zmd, i);
>>> + }
>>> DMDEBUG("(%s): Reclaim (%u): %s, %u%% free zones (%u/%u cache %u/%u random)",
>>> dmz_metadata_label(zmd),
>>> zrc->kc_throttle.throttle,
>>> (dmz_target_idle(zrc) ? "Idle" : "Busy"),
>>> p_unmap, dmz_nr_unmap_cache_zones(zmd),
>>> dmz_nr_cache_zones(zmd),
>>> - dmz_nr_unmap_rnd_zones(zmd),
>>> - dmz_nr_rnd_zones(zmd));
>>> + nr_unmap_rnd, nr_rnd);
>>>
>>> ret = dmz_do_reclaim(zrc);
>>> if (ret && ret != -EINTR) {
>
> In the light of this I guess there is a benefit from having the counters
> in the metadata; that indeed would save us to having to export the
> number of devices.
> I'll give it a go with the next round.
>
>>> diff --git a/drivers/md/dm-zoned-target.c b/drivers/md/dm-zoned-target.c
>>> index bca9a611b8dd..f34fcc3f7cc6 100644
>>> --- a/drivers/md/dm-zoned-target.c
>>> +++ b/drivers/md/dm-zoned-target.c
>>> @@ -13,8 +13,6 @@
>>>
>>> #define DMZ_MIN_BIOS 8192
>>>
>>> -#define DMZ_MAX_DEVS 2
>>> -
>>> /*
>>> * Zone BIO context.
>>> */
>>> @@ -40,9 +38,10 @@ struct dm_chunk_work {
>>> * Target descriptor.
>>> */
>>> struct dmz_target {
>>> - struct dm_dev *ddev[DMZ_MAX_DEVS];
>>> + struct dm_dev **ddev;
>>> + unsigned int nr_ddevs;
>>>
>>> - unsigned long flags;
>>> + unsigned int flags;
>>>
>>> /* Zoned block device information */
>>> struct dmz_dev *dev;
>>> @@ -764,7 +763,7 @@ static void dmz_put_zoned_device(struct dm_target *ti)
>>> struct dmz_target *dmz = ti->private;
>>> int i;
>>>
>>> - for (i = 0; i < DMZ_MAX_DEVS; i++) {
>>> + for (i = 0; i < dmz->nr_ddevs; i++) {
>>> if (dmz->ddev[i]) {
>>> dm_put_device(ti, dmz->ddev[i]);
>>> dmz->ddev[i] = NULL;
>>> @@ -777,21 +776,35 @@ static int dmz_fixup_devices(struct dm_target *ti)
>>> struct dmz_target *dmz = ti->private;
>>> struct dmz_dev *reg_dev, *zoned_dev;
>>> struct request_queue *q;
>>> + sector_t zone_nr_sectors = 0;
>>> + int i;
>>>
>>> /*
>>> - * When we have two devices, the first one must be a regular block
>>> - * device and the second a zoned block device.
>>> + * When we have more than on devices, the first one must be a
>>> + * regular block device and the others zoned block devices.
>>> */
>>> - if (dmz->ddev[0] && dmz->ddev[1]) {
>>> + if (dmz->nr_ddevs > 1) {
>>> reg_dev = &dmz->dev[0];
>>> if (!(reg_dev->flags & DMZ_BDEV_REGULAR)) {
>>> ti->error = "Primary disk is not a regular device";
>>> return -EINVAL;
>>> }
>>> - zoned_dev = &dmz->dev[1];
>>> - if (zoned_dev->flags & DMZ_BDEV_REGULAR) {
>>> - ti->error = "Secondary disk is not a zoned device";
>>> - return -EINVAL;
>>> + for (i = 1; i < dmz->nr_ddevs; i++) {
>>> + zoned_dev = &dmz->dev[i];
>>> + if (zoned_dev->flags & DMZ_BDEV_REGULAR) {
>>> + ti->error = "Secondary disk is not a zoned device";
>>> + return -EINVAL;
>>> + }
>>> + q = bdev_get_queue(zoned_dev->bdev);
>>
>> May be add a comment here that we must check that all zoned devices have the
>> same zone size ?
>>
>
> I thought it was self-explanatory; but maybe not.
> Will be adding it.
It is indeed not too hard to figure out. But a plain english sentence is nice too :)
>
> Cheers,
>
> Hannes
>
--
Damien Le Moal
Western Digital Research
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