From: Song Liu <song@kernel.org>
To: Christopher Unkel <cunkel@drivescale.com>
Cc: linux-raid <linux-raid@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] md: align superblock writes to physical blocks
Date: Thu, 22 Oct 2020 22:46:17 -0700 [thread overview]
Message-ID: <CAPhsuW50ON69Z=Wq30fEw0M2mGtXYKQCUNUbDS78AUe--nNZSg@mail.gmail.com> (raw)
In-Reply-To: <20201023033130.11354-2-cunkel@drivescale.com>
On Thu, Oct 22, 2020 at 8:31 PM Christopher Unkel <cunkel@drivescale.com> wrote:
>
> Writes of the md superblock are aligned to the logical blocks of the
> containing device, but no attempt is made to align them to physical
> block boundaries. This means that on a "512e" device (4k physical, 512
> logical) every superblock update hits the 512-byte emulation and the
> possible associated performance penalty.
>
> Respect the physical block alignment when possible.
>
> Signed-off-by: Christopher Unkel <cunkel@drivescale.com>
> ---
> drivers/md/md.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 98bac4f304ae..2b42850acfb3 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -1732,6 +1732,21 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
> && rdev->new_data_offset < sb_start + (rdev->sb_size/512))
> return -EINVAL;
>
> + /* Respect physical block size if feasible. */
> + bmask = queue_physical_block_size(rdev->bdev->bd_disk->queue)-1;
> + if (!((rdev->sb_start * 512) & bmask) && (rdev->sb_size & bmask)) {
> + int candidate_size = (rdev->sb_size | bmask) + 1;
> +
> + if (minor_version) {
> + int sectors = candidate_size / 512;
> +
> + if (rdev->data_offset >= sb_start + sectors
> + && rdev->new_data_offset >= sb_start + sectors)
> + rdev->sb_size = candidate_size;
> + } else if (bmask <= 4095)
> + rdev->sb_size = candidate_size;
> + }
In super_1_load() and super_1_sync(), we have
bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
I think we should replace it with queue_physical_block_size() so the logic is
cleaner. Would this work?
Thanks,
Song
next prev parent reply other threads:[~2020-10-23 5:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 3:31 [PATCH 0/3] mdraid sb and bitmap write alignment on 512e drives Christopher Unkel
2020-10-23 3:31 ` [PATCH 1/3] md: align superblock writes to physical blocks Christopher Unkel
2020-10-23 5:46 ` Song Liu [this message]
2020-10-23 8:29 ` Christoph Hellwig
2020-10-23 3:31 ` [PATCH 2/3] md: factor sb write alignment check into function Christopher Unkel
2020-10-23 3:31 ` [PATCH 3/3] md: pad writes to end of bitmap to physical blocks Christopher Unkel
2020-10-23 5:41 ` [PATCH 0/3] mdraid sb and bitmap write alignment on 512e drives Song Liu
2020-10-23 7:03 ` Chris Unkel
2020-11-02 7:04 ` Xiao Ni
2020-11-02 18:59 ` Chris Unkel
2020-11-03 8:32 ` Xiao Ni
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