Messages in this thread | | | Date | Tue, 24 May 2022 07:22:48 +0200 | Subject | Re: [PATCH v5 6/7] null_blk: use zone_size_sects_shift for power of 2 zoned devices | From | Hannes Reinecke <> |
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On 5/23/22 18:16, Pankaj Raghav wrote: > Instead of doing is_power_of_2 and ilog2 operation for every IO, cache > the zone_size_sects_shift variable and use it for power of 2 zoned > devices. > > This variable will be set to zero for non power of 2 zoned devices. > > Suggested-by: Damien Le Moal <damien.lemoal@wdc.com> > Signed-off-by: Pankaj Raghav <p.raghav@samsung.com> > --- > drivers/block/null_blk/null_blk.h | 6 ++++++ > drivers/block/null_blk/zoned.c | 10 ++++++++-- > 2 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/drivers/block/null_blk/null_blk.h b/drivers/block/null_blk/null_blk.h > index 78eb56b0ca55..3d6e41a9491f 100644 > --- a/drivers/block/null_blk/null_blk.h > +++ b/drivers/block/null_blk/null_blk.h > @@ -74,6 +74,12 @@ struct nullb_device { > unsigned int imp_close_zone_no; > struct nullb_zone *zones; > sector_t zone_size_sects; > + /* > + * zone_size_sects_shift is only useful when the zone size is > + * power of 2. This variable is set to zero when zone size is non > + * power of 2. > + */ > + unsigned int zone_size_sects_shift; > bool need_zone_res_mgmt; > spinlock_t zone_res_lock; > > diff --git a/drivers/block/null_blk/zoned.c b/drivers/block/null_blk/zoned.c > index 00c34e65ef0a..806bef98ac83 100644 > --- a/drivers/block/null_blk/zoned.c > +++ b/drivers/block/null_blk/zoned.c > @@ -13,8 +13,8 @@ static inline sector_t mb_to_sects(unsigned long mb) > > static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect) > { > - if (is_power_of_2(dev->zone_size_sects)) > - return sect >> ilog2(dev->zone_size_sects); > + if (dev->zone_size_sects_shift) > + return sect >> dev->zone_size_sects_shift; > > return div64_u64(sect, dev->zone_size_sects); > } > @@ -82,6 +82,12 @@ 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); > + > + if (is_power_of_2(dev->zone_size_sects)) > + dev->zone_size_sects_shift = ilog2(dev->zone_size_sects); > + else > + dev->zone_size_sects_shift = 0; > + > dev->nr_zones = > div64_u64(roundup(dev_capacity_sects, dev->zone_size_sects), > dev->zone_size_sects); Reviewed-by: Hannes Reinecke <hare@suse.de>
Cheers,
Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Ivo Totev, Andrew Myers, Andrew McDonald, Martje Boudien Moerman
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