Re: [RFC PATCH] ext3 writepage() journal avoidance

From: Badari Pulavarty
Date: Fri Mar 10 2006 - 11:36:46 EST


On Fri, 2006-03-10 at 11:19 -0500, Dave Jones wrote:
> On Fri, Mar 10, 2006 at 09:43:57AM +0100, Arjan van de Ven wrote:
> > On Fri, 2006-03-10 at 00:23 -0800, Andrew Morton wrote:
> > > Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:
> > > >
> > > >
> > > > > I'm not sure that PageMappedToDisk() gets set in all the right places
> > > > > though - it's mainly for the `nobh' handling and block_prepare_write()
> > > > > would need to be taught to set it. I guess that'd be a net win, even if
> > > > > only ext3 uses it..
> > > >
> > > > btw is nobh mature enough yet to become the default, or to just go away
> > > > entirely as option ?
> > >
> > > I don't know how much usage it's had, sorry. It's only allowed in
> > > data=writeback mode and not many people seem to use even that.
> >
> > would you be prepared to turn it on by default in -mm for a bit to see
> > how it holds up? The concept seems valuable in itself, so much so that I
> > feel this should be 1) on always by default when possible and 2) isn't
> > really the kind of thing that should be a long term option; not having
> > it almost is a -o pleaseAddThisBug option for each bug fixed.
>
> It'd be good to get that hammered on, as it doesn't see hardly any testing
> based upon the experiments I did sometime last year. It left me with
> an unmountable root filesystem :-/

Yuck. You are talking about "nobh" option for writeback mode, correct ?
Have any idea on what you were doing ?

Wondering why ? The changes are extremely simple (since I don't handle
pagesize > blocksize + limit truncate handling and fallback to bh code).

Thanks,
Badari

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