Re: [RFC] relaxed barrier semantics

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Thu, Aug 05, 2010 at 04:52:15PM +0200, Hannes Reinecke wrote:
> I still think that implementing ordered tags is the correct way of
> doing things, implementation details notwithstanding.
> 
> It looks better conceptually than using FUA, and would be easier
> from the request-queue side of things.

Sorry, but ordered tags are in no way a replacement for the FUA bit.
Admittedly the current barrier semantics are confusing because they
mix up to only minimally related things:

 a) cache flushing
 b) ordering

a) is what we really need from the filesystems point of view.  b) is
something all our filesystems can do ourself.  We could use ordered
tags to offload it, and I'd be happy if someone could prove that
we're getting speedups from it, but it certainly does not replace a).

With enough outstanding tags, be that using ordered tags or software
managed ordering we could fill the disk enough that we don't need to
write cache, but again that'll need a lot of benchmarking.
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [SCSI Target Devel]     [Linux SCSI Target Infrastructure]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Linux IIO]     [Samba]     [Device Mapper]
  Powered by Linux