From: Jens Axboe <jens.axboe@oracle.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
stern@rowland.harvard.edu, linux-kernel@vger.kernel.org,
antonio.lin@alcormicro.com, david.vrabel@csr.com
Subject: Re: Scatter-gather list constraints
Date: Thu, 26 Jun 2008 15:00:34 +0200 [thread overview]
Message-ID: <20080626130034.GX20851@kernel.dk> (raw)
In-Reply-To: <48639180.2090005@firstfloor.org>
On Thu, Jun 26 2008, Andi Kleen wrote:
>
> > On the fs side, just setting a hw block size of 1k should fix the
> > problem, since that'd be your minimum transfer size AND alignment there
> > even for O_DIRECT IO.
>
> XFS used to force 512 byte IOs for its log IO. Not sure
> that was ever fixed. If it was fixed it likely required a disk format
> change (I think s390 ran into a problem like this)
Issuing IO less than the hardware block size is illegal, so if they do
that then they can't be supported on hardware with > 512b block sizes.
Someone has to do the RMW for such an operation and we don't do it in
drivers.
--
Jens Axboe
next prev parent reply other threads:[~2008-06-26 13:11 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-20 20:30 Scatter-gather list constraints Alan Stern
2008-06-20 20:50 ` David Miller
2008-06-21 13:59 ` Andi Kleen
2008-06-21 14:54 ` Alan Stern
2008-06-21 15:21 ` Andi Kleen
2008-06-21 21:50 ` Alan Stern
2008-06-21 23:00 ` Andi Kleen
2008-06-22 14:35 ` Alan Stern
2008-06-24 10:41 ` FUJITA Tomonori
2008-06-24 14:57 ` Alan Stern
2008-06-25 0:18 ` FUJITA Tomonori
2008-06-25 14:23 ` Alan Stern
2008-06-26 2:06 ` FUJITA Tomonori
2008-06-26 5:39 ` FUJITA Tomonori
2008-06-26 6:35 ` Jens Axboe
2008-06-26 6:58 ` FUJITA Tomonori
2008-06-26 12:39 ` Jens Axboe
2008-06-26 12:54 ` Andi Kleen
2008-06-26 13:00 ` Jens Axboe [this message]
2008-06-26 15:12 ` Alan Stern
2008-06-26 17:41 ` Jens Axboe
2008-08-27 21:32 ` Alan Stern
2008-06-26 15:16 ` Boaz Harrosh
2008-06-26 17:39 ` Jens Axboe
2008-06-26 14:18 ` Alan Stern
2008-06-23 14:46 ` David Vrabel
2008-06-23 15:12 ` Alan Stern
2008-06-23 19:06 ` David Vrabel
2008-06-23 19:45 ` Alan Stern
2008-06-23 21:53 ` Stefan Richter
2008-06-25 4:02 ` Perez-Gonzalez, Inaky
2008-06-25 14:24 ` Alan Stern
2008-06-26 16:43 ` Perez-Gonzalez, Inaky
2008-06-26 19:34 ` Alan Stern
2008-06-26 22:39 ` Inaky Perez-Gonzalez
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