lkml.org 
[lkml]   [2010]   [Aug]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/5] virtio_blk: implement REQ_FLUSH/FUA support
Hello,

On 08/16/2010 08:33 PM, Christoph Hellwig wrote:
> On Mon, Aug 16, 2010 at 06:52:00PM +0200, Tejun Heo wrote:
>> From: Tejun Heo <tj@kernle.org>
>>
>> Remove now unused REQ_HARDBARRIER support and implement REQ_FLUSH/FUA
>> support instead. A new feature flag VIRTIO_BLK_F_FUA is added to
>> indicate the support for FUA.
>
> I'm not sure it's worth it. The pure REQ_FLUSH path works not and is
> well tested with kvm/qemu. We can still easily add a FUA bit, and
> even a pre-flush bit if the protocol roundtrips matter in real life
> benchmarking.

Hmmm... the underlying storage could be md/dm RAIDs in which case FUA
should be cheaper than FLUSH.

Thanks.

--
tejun


\
 
 \ /
  Last update: 2010-08-17 10:23    [W:0.089 / U:0.804 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site