From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Robert Hancock <hancockrwd@gmail.com>
Cc: "Gao, Yunpeng" <yunpeng.gao@intel.com>,
"linux-ide@vger.kernel.org" <linux-ide@vger.kernel.org>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>
Subject: Re: How to make kernel block layer generate bigger request in the request queue?
Date: Fri, 09 Apr 2010 22:05:50 -0400 [thread overview]
Message-ID: <yq1y6gwt62p.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <4BBFBE3E.5070605@gmail.com> (Robert Hancock's message of "Fri, 09 Apr 2010 17:54:38 -0600")
>>>>> "Robert" == Robert Hancock <hancockrwd@gmail.com> writes:
>> Did I miss something to make the block layer generate bigger size
>> data for every request in the request queue? Below is part of my
>> source code. Any comments are highly appreciated. Thank you in
>> advance.
Robert> 8 sectors is 4KB, that's the size of a page. If the pages that
Robert> are being written are not physically contiguous that may be the
Robert> best the block layer can do with the constraints you've given it
Robert> (not supporting any more than 1 DMA segment).
Correct. It's quite unlikely for pages to be contiguous so this is the
best we can do.
Having recently done a cleanup of our segment handling I became aware
that there are many MMC devices that are single-element only. This was
probably a sufficient approach for 32MB devices but it's time to get
with the program and implement proper scatter-gather.
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2010-04-10 2:06 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-09 14:07 How to make kernel block layer generate bigger request in the request queue? Gao, Yunpeng
2010-04-09 23:54 ` Robert Hancock
2010-04-10 2:05 ` Martin K. Petersen [this message]
2010-04-10 14:58 ` James Bottomley
2010-04-12 18:26 ` Martin K. Petersen
2010-04-12 19:58 ` James Bottomley
2010-04-13 15:06 ` Gao, Yunpeng
2010-04-13 15:20 ` Alan Cox
2010-04-19 6:42 ` Gao, Yunpeng
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