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From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Tom Yan <tom.ty89@gmail.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
	linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org
Subject: Re: configurable discard parameters
Date: Tue, 23 Jun 2015 14:26:18 -0400	[thread overview]
Message-ID: <yq1egl246yd.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <CAGnHSEkF+uXh2=wpq9dwjK8_NrjF5kqcasXeuCF_=TONu6Q7Cw@mail.gmail.com> (Tom Yan's message of "Wed, 24 Jun 2015 01:24:12 +0800")

>>>>> "Tom" == Tom Yan <tom.ty89@gmail.com> writes:

Tom> So when libata issue ATA commands with ranges of 65535 sectors,
Tom> only 65535-(65535%8) = 65528 sectors are discarded,

That's unfortunate but TRIM is advisory so the drive is free to ignore
all or parts of the request.

What happens if you discard sectors 0-6 and then sector 7?

Tom> I can workaround this by specifying --step in blkdiscard, but I
Tom> think the kernel should have a param configurable for general.

This is on the Intel 530? What does the drive report in
/sys/block/sdN/queue/discard_zeroes_data?

-- 
Martin K. Petersen	Oracle Linux Engineering

  reply	other threads:[~2015-06-23 18:26 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-20 17:12 configurable discard parameters Tom Yan
2015-06-21  0:20 ` Martin K. Petersen
2015-06-21  7:03   ` Tom Yan
2015-06-21  8:05     ` Tom Yan
2015-06-21 12:36       ` Tom Yan
2015-06-21 20:30         ` Tom Yan
2015-06-22 20:57           ` Martin K. Petersen
2015-06-23 14:16             ` Tom Yan
2015-06-23 15:36               ` Martin K. Petersen
2015-06-23 16:41                 ` Tom Yan
2015-06-23 17:03                   ` Martin K. Petersen
2015-06-23 17:24                     ` Tom Yan
2015-06-23 18:26                       ` Martin K. Petersen [this message]
2015-06-23 21:25                         ` Tom Yan
2015-06-24  2:55                           ` Martin K. Petersen
2015-06-24 12:46                             ` Tom Yan
2015-06-25  1:15                               ` Martin K. Petersen
2015-06-26  7:05                                 ` Tom Yan

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