From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Shaun Tancheff <shaun.tancheff@seagate.com>
Cc: Tom Yan <tom.ty89@gmail.com>, Shaun Tancheff <shaun@tancheff.com>,
linux-ide@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>, Tejun Heo <tj@kernel.org>,
Josh Bingaman <josh.bingaman@seagate.com>
Subject: Re: [PATCH v5 2/2] Add support for SCT Write Same
Date: Wed, 10 Aug 2016 21:33:51 -0400 [thread overview]
Message-ID: <yq1popgrsw0.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <CAJVOszAQZ_ukCkdBkkn5_iEPUCQKLBF=o-o0v+U=cWiOgQNSRg@mail.gmail.com> (Shaun Tancheff's message of "Wed, 10 Aug 2016 09:34:53 -0500")
>>>>> "Shaun" == Shaun Tancheff <shaun.tancheff@seagate.com> writes:
Shaun,
Shaun> You are correct in that we can advertise the larger limit in
Shaun> ata_scsi_dev_config() when only SCT write same is supported
Shaun> rather than fall back to WS10.
I deliberately capped WRITE SAME to 64K blocks unless otherwise reported
by the device because:
a) Several older drives supported the WRITE SAME(16) command but
ignored the upper bytes of the transfer length effectively
turning it into a WRITE SAME(10).
b) 64K blocks was the sweet spot for older drives as well, a
size commonly used by RAID array firmwares that were the only
commonplace users of the WRITE SAME family.
Shaun> I really am not sure what would be considered the correct
Shaun> solution though. I believe that the WRITE SAME defaults are
Shaun> currently being chosen around physical limits.
Lacking a solid reporting facility in the spec, I suggest you just leave
it unset and let the SCSI defaults apply.
Shaun> I think we can also bump the command timeout for WRITE SAME?
The default WRITE SAME timeout is 120s.
--
Martin K. Petersen Oracle Linux Engineering
prev parent reply other threads:[~2016-08-11 1:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-10 1:00 [PATCH v5 0/2] Add support for SCT Write Same Shaun Tancheff
2016-08-10 1:00 ` [PATCH v5 1/2] Use kmap_atomic when rewriting attached page Shaun Tancheff
2016-08-10 10:56 ` Tom Yan
2016-08-10 12:26 ` Shaun Tancheff
2016-08-11 14:13 ` Christoph Hellwig
2016-08-10 1:00 ` [PATCH v5 2/2] Add support for SCT Write Same Shaun Tancheff
2016-08-10 6:31 ` Tom Yan
2016-08-10 11:30 ` Tom Yan
2016-08-10 14:34 ` Shaun Tancheff
2016-08-10 16:50 ` Tom Yan
2016-08-10 18:29 ` Shaun Tancheff
2016-08-11 8:04 ` Tom Yan
2016-08-11 1:47 ` Martin K. Petersen
2016-08-11 8:46 ` Tom Yan
2016-08-12 1:18 ` Martin K. Petersen
2016-08-11 1:33 ` Martin K. Petersen [this message]
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