lkml.org 
[lkml]   [2016]   [Sep]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [Nbd] [PATCH][V3] nbd: add multi-connection support
From
Date
On 09/29/2016 12:41 PM, Wouter Verhelst wrote:
> On Thu, Sep 29, 2016 at 10:03:50AM -0400, Josef Bacik wrote:
>> So think of it like normal disks with multiple channels. We don't send flushes
>> down all the hwq's to make sure they are clear, we leave that decision up to the
>> application (usually a FS of course).
>
> Well, when I asked earlier, Christoph said[1] that blk-mq assumes that
> when a FLUSH is sent over one channel, and the reply comes in, that all
> commands which have been received, regardless of which channel they were
> received over, have reched disk.
>
> [1] Message-ID: <20160915122304.GA15501@infradead.org>
>
> It is impossible for nbd to make such a guarantee, due to head-of-line
> blocking on TCP.
>

Huh I missed that. Yeah that's not possible for us for sure, I think my option
idea is the less awful way forward if we want to address that limitation. Thanks,

Josef

\
 
 \ /
  Last update: 2016-09-29 19:01    [W:0.070 / U:1.392 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site