From: Ming Lei <ming.lei@redhat.com>
To: Mike Snitzer <snitzer@redhat.com>
Cc: linux-block@vger.kernel.org, dm-devel@redhat.com,
Vijayendra Suman <vijayendra.suman@oracle.com>
Subject: Re: [PATCH 2/3] block: use lcm_not_zero() when stacking chunk_sectors
Date: Sat, 12 Sep 2020 21:58:22 +0800 [thread overview]
Message-ID: <20200912135822.GB210077@T590> (raw)
In-Reply-To: <20200911215338.44805-3-snitzer@redhat.com>
On Fri, Sep 11, 2020 at 05:53:37PM -0400, Mike Snitzer wrote:
> Like 'io_opt', blk_stack_limits() should stack 'chunk_sectors' using
> lcm_not_zero() rather than min_not_zero() -- otherwise the final
> 'chunk_sectors' could result in sub-optimal alignment of IO to
> component devices in the IO stack.
>
> Also, if 'chunk_sectors' isn't a multiple of 'physical_block_size'
> then it is a bug in the driver and the device should be flagged as
> 'misaligned'.
>
> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
> ---
> block/blk-settings.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/block/blk-settings.c b/block/blk-settings.c
> index 76a7e03bcd6c..b09642d5f15e 100644
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> @@ -534,6 +534,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
>
> t->io_min = max(t->io_min, b->io_min);
> t->io_opt = lcm_not_zero(t->io_opt, b->io_opt);
> + t->chunk_sectors = lcm_not_zero(t->chunk_sectors, b->chunk_sectors);
>
> /* Physical block size a multiple of the logical block size? */
> if (t->physical_block_size & (t->logical_block_size - 1)) {
> @@ -556,6 +557,13 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
> ret = -1;
> }
>
> + /* chunk_sectors a multiple of the physical block size? */
> + if (t->chunk_sectors & (t->physical_block_size - 1)) {
> + t->chunk_sectors = 0;
> + t->misaligned = 1;
> + ret = -1;
> + }
> +
> t->raid_partial_stripes_expensive =
> max(t->raid_partial_stripes_expensive,
> b->raid_partial_stripes_expensive);
> @@ -594,10 +602,6 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
> t->discard_granularity;
> }
>
> - if (b->chunk_sectors)
> - t->chunk_sectors = min_not_zero(t->chunk_sectors,
> - b->chunk_sectors);
> -
> t->zoned = max(t->zoned, b->zoned);
> return ret;
> }
Looks fine:
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Thanks,
Ming
next prev parent reply other threads:[~2020-09-12 13:58 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <529c2394-1b58-b9d8-d462-1f3de1b78ac8@oracle.com>
2020-09-10 14:24 ` Revert "dm: always call blk_queue_split() in dm_process_bio()" Mike Snitzer
2020-09-10 19:29 ` Vijayendra Suman
2020-09-15 1:33 ` Mike Snitzer
2020-09-15 17:03 ` Mike Snitzer
2020-09-16 14:56 ` Vijayendra Suman
2020-09-11 12:20 ` Ming Lei
2020-09-11 16:13 ` Mike Snitzer
2020-09-11 21:53 ` [PATCH 0/3] block: a few chunk_sectors fixes/improvements Mike Snitzer
2020-09-11 21:53 ` [PATCH 1/3] block: fix blk_rq_get_max_sectors() to flow more carefully Mike Snitzer
2020-09-12 13:52 ` Ming Lei
2020-09-14 0:43 ` Damien Le Moal
2020-09-14 14:52 ` Mike Snitzer
2020-09-14 23:28 ` Damien Le Moal
2020-09-15 2:03 ` Ming Lei
2020-09-15 2:15 ` Damien Le Moal
2020-09-14 14:49 ` Mike Snitzer
2020-09-15 1:50 ` Ming Lei
2020-09-14 0:46 ` Damien Le Moal
2020-09-14 15:03 ` Mike Snitzer
2020-09-15 1:09 ` Damien Le Moal
2020-09-15 4:21 ` Damien Le Moal
2020-09-15 8:01 ` Ming Lei
2020-09-11 21:53 ` [PATCH 2/3] block: use lcm_not_zero() when stacking chunk_sectors Mike Snitzer
2020-09-12 13:58 ` Ming Lei [this message]
2020-09-11 21:53 ` [PATCH 3/3] block: allow 'chunk_sectors' to be non-power-of-2 Mike Snitzer
2020-09-12 14:06 ` Ming Lei
2020-09-14 2:43 ` Keith Busch
2020-09-14 0:55 ` Damien Le Moal
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