From: Joe Thornber <thornber@redhat.com>
To: device-mapper development <dm-devel@redhat.com>
Subject: Re: DM-Cache Writeback & Direct IO?
Date: Wed, 8 Jul 2015 15:48:29 +0100 [thread overview]
Message-ID: <20150708144829.GA5058@rh-vpn> (raw)
In-Reply-To: <559CE76E.6020504@evilazrael.de>
On Wed, Jul 08, 2015 at 11:03:42AM +0200, Christoph Nelles wrote:
> Hi,
>
> Can the dm-cache writeback cache buffer direct IO or goes direct IO
> always immediately to the origin device?
Yes, the device mapper layer knows nothing about direct IO vs page
cache IO.
> I am currently performing tests and see that random direct write IO
> never hits the cache, even after overwriting the same region over
> and over.
Could you try with the latest kernels and the new smq policy please?
- Joe
next prev parent reply other threads:[~2015-07-08 14:48 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-08 9:03 DM-Cache Writeback & Direct IO? Christoph Nelles
2015-07-08 14:48 ` Joe Thornber [this message]
2015-07-09 16:51 ` Christoph Nelles
2015-07-21 13:51 ` Christoph Nelles
[not found] <9E0DEE10BA62134F89BB5A513CA84BC3A1A6B5CA@MAILSERVER01.trt9a.local>
[not found] ` <CAEZ+n-j_9QGWi7pdZY71VAmF-tnuRWb_8neWBd3iKMTm-yQU1A@mail.gmail.com>
2015-07-08 17:55 ` Leonardo Santos
2015-07-09 15:51 ` Christoph Nelles
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