Messages in this thread | | | Date | Fri, 10 Mar 2006 06:58:05 -0800 | From | Badari Pulavarty <> | Subject | Re: [RFC PATCH] ext3 writepage() journal avoidance |
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Andrew Morton wrote:
>Arjan van de Ven <arjan@infradead.org> wrote: > >>On Fri, 2006-03-10 at 00:23 -0800, Andrew Morton wrote: >> > Arjan van de Ven <arjan@infradead.org> 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? >> > >spose so. One would have to test it a bit first, make sure that it still >works. Performance testing with PAGE_SIZE much-greater-than blocksize >would be needed. > I did nobh option only for writeback mode + only if PAGE_SIZE == blocksize case :( I guess I could enhance it for PAGE_SIZE > blocksize case also.
Doing it for ordered mode, journal mode is hard - due to transactions & ordering. As you suggested while ago, we need a new mode. I hate to add new modes since no one will be using it (unless we decide to make it default). Thats the reason why I spent little time doing nobh option for writeback mode.
> >Unfortunately there's no `-o bh' (nonobh?) to turn it back on again if it >causes problems.. >
Can be added easily. I will send out a patch for this.
Thanks, Badari
>
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