Re: [PATCH 4/4] block: Optionally snapshot page contents to provide stable pages during write

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

 



On Thu, Dec 13, 2012 at 06:10:49PM -0800, Darrick J. Wong wrote:
> On Thu, Dec 13, 2012 at 05:48:06PM -0800, Andy Lutomirski wrote:
> > On 12/13/2012 12:08 AM, Darrick J. Wong wrote:
> > > Several complaints have been received regarding long file write latencies when
> > > memory pages must be held stable during writeback.  Since it might not be
> > > acceptable to stall programs for the entire duration of a page write (which may
> > > take many milliseconds even on good hardware), enable a second strategy wherein
> > > pages are snapshotted as part of submit_bio; the snapshot can be held stable
> > > while writes continue.
> > > 
> > > This provides a band-aid to provide stable page writes on jbd without needing
> > > to backport the fixed locking scheme in jbd2.  A mount option is added to ext4
> > > to allow administrators to enable it there.
> > 
> > I'm a bit confused as to what it has to do with ext3.  Wouldn't this be
> > useful as a mount option everywhere, though?
> 
> ext3 requires snapshots; the rest are ok with either strategy.
> 
> *If* snapshotting is generally liked, then yes I'll go redo it as a vfs mount
> option.

It's copying every single IO, right? If so, then please don't
propagate any further than is necessary to fix the broken
filesystems...

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux