From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Mike Snitzer <snitzer@kernel.org>,
linux-block@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: Re: [PATCH 1/2] sd: also set max_user_sectors when setting max_sectors
Date: Thu, 23 May 2024 14:53:40 -0400 [thread overview]
Message-ID: <yq1o78wjrsw.fsf@ca-mkp.ca.oracle.com> (raw)
In-Reply-To: <20240523182618.602003-2-hch@lst.de> (Christoph Hellwig's message of "Thu, 23 May 2024 20:26:13 +0200")
Christoph,
> sd can set a max_sectors value that is lower than the max_hw_sectors
> limit based on the block limits VPD page. While this is rather
> unusual,
It's not particularly unusual. Virtually all arrays have a much smaller
stripe or cache line size than what the average HBA can handle in one
transfer. Using the device's preferred I/O size to configure max_sectors
made a substantial difference performance-wise.
> it used to work until the max_user_sectors field was split out to
> cleanly deal with conflicting hardware and user limits when the
> hardware limit changes. Also set max_user_sectors to ensure the limit
> can properly be stacked.
Fine for a quick fix.
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2024-05-23 18:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-23 18:26 fix stacking of sd-imposed max_sectors Christoph Hellwig
2024-05-23 18:26 ` [PATCH 1/2] sd: also set max_user_sectors when setting max_sectors Christoph Hellwig
2024-05-23 18:53 ` Martin K. Petersen [this message]
2024-05-24 7:51 ` Christoph Hellwig
2024-05-23 18:26 ` [PATCH 2/2] block: stack max_user_sectors Christoph Hellwig
2024-05-23 18:54 ` Martin K. Petersen
2024-05-28 12:57 ` fix stacking of sd-imposed max_sectors Jens Axboe
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