From: Niklas Cassel <Niklas.Cassel@wdc.com>
To: Damien Le Moal <Damien.LeMoal@wdc.com>
Cc: Jonathan Corbet <corbet@lwn.net>, Jens Axboe <axboe@kernel.dk>,
Keith Busch <kbusch@kernel.org>, Christoph Hellwig <hch@lst.de>,
Sagi Grimberg <sagi@grimberg.me>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>
Subject: Re: [PATCH 1/2] block: add max_open_zones to blk-sysfs
Date: Thu, 2 Jul 2020 12:37:57 +0000 [thread overview]
Message-ID: <20200702123755.GA609677@localhost.localdomain> (raw)
In-Reply-To: <CY4PR04MB3751C2C03ACCA263541DA348E76F0@CY4PR04MB3751.namprd04.prod.outlook.com>
On Tue, Jun 30, 2020 at 01:49:41AM +0000, Damien Le Moal wrote:
> On 2020/06/16 19:28, Niklas Cassel wrote:
> > diff --git a/drivers/nvme/host/zns.c b/drivers/nvme/host/zns.c
> > index c08f6281b614..af156529f3b6 100644
> > --- a/drivers/nvme/host/zns.c
> > +++ b/drivers/nvme/host/zns.c
> > @@ -82,6 +82,7 @@ int nvme_update_zone_info(struct gendisk *disk, struct nvme_ns *ns,
> >
> > q->limits.zoned = BLK_ZONED_HM;
> > blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
> > + blk_queue_max_open_zones(q, le32_to_cpu(id->mor) + 1);
> > free_data:
> > kfree(id);
> > return status;
> > diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
> > index 183a20720da9..aa3564139b40 100644
> > --- a/drivers/scsi/sd_zbc.c
> > +++ b/drivers/scsi/sd_zbc.c
> > @@ -717,6 +717,10 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
> > /* The drive satisfies the kernel restrictions: set it up */
> > blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
> > blk_queue_required_elevator_features(q, ELEVATOR_F_ZBD_SEQ_WRITE);
> > + if (sdkp->zones_max_open == U32_MAX)
> > + blk_queue_max_open_zones(q, 0);
> > + else
> > + blk_queue_max_open_zones(q, sdkp->zones_max_open);
>
> This is correct only for host-managed drives. Host-aware models define the
> "OPTIMAL NUMBER OF OPEN SEQUENTIAL WRITE PREFERRED ZONES" instead of a maximum
> number of open sequential write required zones.
>
> Since the standard does not actually explicitly define what the value of the
> maximum number of open sequential write required zones should be for a
> host-aware drive, I would suggest to always have the max_open_zones value set to
> 0 for host-aware disks.
Isn't this already the case?
At least according to the comments:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/scsi/sd_zbc.c?h=v5.8-rc3#n555
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/scsi/sd_zbc.c?h=v5.8-rc3#n561
We seem to set
sdkp->zones_max_open = 0;
for host-aware, and
sdkp->zones_max_open = get_unaligned_be32(&buf[16]);
for host-managed.
So the blk_queue_max_open_zones(q, sdkp->zones_max_open) call in
sd_zbc_read_zones() should already export this new sysfs property
as 0 for host-aware disks.
Kind regards,
Niklas
>
> > nr_zones = round_up(sdkp->capacity, zone_blocks) >> ilog2(zone_blocks);
> >
> > /* READ16/WRITE16 is mandatory for ZBC disks */
> > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> > index 8fd900998b4e..2f332f00501d 100644
> > --- a/include/linux/blkdev.h
> > +++ b/include/linux/blkdev.h
> > @@ -520,6 +520,7 @@ struct request_queue {
> > unsigned int nr_zones;
> > unsigned long *conv_zones_bitmap;
> > unsigned long *seq_zones_wlock;
> > + unsigned int max_open_zones;
> > #endif /* CONFIG_BLK_DEV_ZONED */
> >
> > /*
> > @@ -729,6 +730,17 @@ static inline bool blk_queue_zone_is_seq(struct request_queue *q,
> > return true;
> > return !test_bit(blk_queue_zone_no(q, sector), q->conv_zones_bitmap);
> > }
> > +
> > +static inline void blk_queue_max_open_zones(struct request_queue *q,
> > + unsigned int max_open_zones)
> > +{
> > + q->max_open_zones = max_open_zones;
> > +}
> > +
> > +static inline unsigned int queue_max_open_zones(const struct request_queue *q)
> > +{
> > + return q->max_open_zones;
> > +}
> > #else /* CONFIG_BLK_DEV_ZONED */
> > static inline unsigned int blk_queue_nr_zones(struct request_queue *q)
> > {
> > @@ -744,6 +756,14 @@ static inline unsigned int blk_queue_zone_no(struct request_queue *q,
> > {
> > return 0;
> > }
> > +static inline void blk_queue_max_open_zones(struct request_queue *q,
> > + unsigned int max_open_zones)
> > +{
> > +}
>
> Why is this one necessary ? For the !CONFIG_BLK_DEV_ZONED case, no driver should
> ever call this function.
Will remove in v2.
next prev parent reply other threads:[~2020-07-02 12:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-16 10:25 [PATCH 0/2] Export max open zones and max active zones to sysfs Niklas Cassel
2020-06-16 10:25 ` [PATCH 1/2] block: add max_open_zones to blk-sysfs Niklas Cassel
2020-06-29 19:41 ` Javier González
2020-06-30 1:49 ` Damien Le Moal
2020-06-30 2:17 ` Damien Le Moal
2020-07-02 12:37 ` Niklas Cassel [this message]
2020-07-03 4:56 ` Damien Le Moal
2020-06-16 10:25 ` [PATCH 2/2] block: add max_active_zones " Niklas Cassel
2020-06-29 19:42 ` Javier González
2020-06-30 1:51 ` Damien Le Moal
2020-07-01 11:16 ` Javier González
2020-07-02 8:41 ` Niklas Cassel
2020-07-02 10:20 ` Javier González
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