lkml.org 
[lkml]   [2007]   [May]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFD] BIO_RW_BARRIER - what it means for devices, filesystems, and dm/md.
On Thu, 31 May 2007, Jens Axboe wrote:

> On Thu, May 31 2007, Phillip Susi wrote:
>> David Chinner wrote:
>>> That sounds like a good idea - we can leave the existing
>>> WRITE_BARRIER behaviour unchanged and introduce a new WRITE_ORDERED
>>> behaviour that only guarantees ordering. The filesystem can then
>>> choose which to use where appropriate....
>>
>> So what if you want a synchronous write, but DON'T care about the order?
>> They need to be two completely different flags which you can choose
>> to combine, or use individually.
>
> If you have a use case for that, we can easily support it as well...
> Depending on the drive capabilities (FUA support or not), it may be
> nearly as slow as a "real" barrier write.

true, but a "real" barrier write could have significant side effects on
other writes that wouldn't happen with a synchronous wrote (a sync wrote
can have other, unrelated writes re-ordered around it, a barrier write
can't)

David Lang
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-05-31 21:25    [W:0.097 / U:0.552 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site