Messages in this thread | | | Date | Wed, 17 May 2006 15:12:12 -0400 | From | Josef Sipek <> | Subject | Re: swapper_space export |
| |
On Wed, May 17, 2006 at 04:52:36PM +0100, Hugh Dickins wrote: > On Wed, 17 May 2006, Arjan van de Ven wrote: > > On Tue, 2006-05-16 at 19:24 -0400, Josef Sipek wrote: > > > I was trying to compile the Unionfs[1] to get it up to sync it up with > > > the kernel developments from the past few months. Anyway, long story > > > short...swapper_space (defined in mm/swap_state.c) is not exported > > > anymore (git commit: 4936967374c1ad0eb3b734f24875e2484c3786cc). This > > > apparently is not an issue for most modules. Troubles arise when the > > > modules include mm.h or any of its relatives. > > > > > > One simply gets a linker error about swapper_space not being defined. > > > The problem is that it is used in mm.h. > > > > don't you think it's really suspect that no other filesystem, in fact no > > other driver in the kernel needs this? Could it just be that unionfs is > > using a wrong API ? Because if that's the case you're patch is just the > > wrong thing. Maybe the unionfs people should try to submit their code > > for review etc...... > > I see no reference to page_mapping() in the unionfs source (and at > present there's no other justifiable modular use of swapper_space); > but my guess would be that Jeff is being more conscientious than is > called for in getting it to sync up with the kernel -
That's what happens when one is trying to get ready to send the code to linux-kernel & fs-devel :)
> The unionfs source does contain its own inline "sync_page" which > comments that it "is copied verbatim from mm/filemap.c". I'm > guessing Jeff has noticed that it's no longer a verbatim copy, > has made it so, and is thereby involving page_mapping().
Good guess, exactly what happened.
> Just use page->mapping as before.
Thanks for the advice.
> (But I notice that unionfs better not have a tmpfs in its union: > the unionfs use of grab_cache_page is not strictly compatible with > the way tmpfs pages are swapped out under memory pressure.)
We have some tmpfs nastiness reported in the bugzilla - I guess this is a good starting point - thanks!
Thanks all, Josef "Jeff" Sipek. - 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/
| |