From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Douglas Gilbert <dgilbert@interlog.com>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>
Subject: Re: bloated workload of SCSI commands at attachment
Date: Thu, 14 Dec 2017 22:02:22 -0500 [thread overview]
Message-ID: <yq17etoofr5.fsf@oracle.com> (raw)
In-Reply-To: <f5b7aceb-0ec0-7ad5-53e3-47ac476b41b4@interlog.com> (Douglas Gilbert's message of "Wed, 13 Dec 2017 09:21:14 -0500")
Doug,
> What seems to be to be new is the three repeated sequence involving
> the "a3 0c" command. That is REPORT SUPPORTED OPERATION CODES.
> Why is the same sequence repeated 3 times?
One invocation is probably partition scanning.
sd_probe calls revalidate twice. It used to be a somewhat tricky dance
of doing it once to get basic device properties, then allocating the
gendisk, and finally doing another revalidate pass to fill out the
remaining fields that had a dependency on a gendisk being instantiated.
Given some of the recent block changes, I am not entirely sure two calls
are required. Would be interesting to test...
--
Martin K. Petersen Oracle Linux Engineering
prev parent reply other threads:[~2017-12-15 3:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-13 14:21 bloated workload of SCSI commands at attachment Douglas Gilbert
2017-12-15 3:02 ` Martin K. Petersen [this message]
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