On Wed, 2007-10-17 at 17:57 +0200, Peter Zijlstra wrote: > On Wed, 2007-10-17 at 11:47 -0400, Trond Myklebust wrote: > > On Wed, 2007-10-17 at 11:45 -0400, Trond Myklebust wrote: > > > On Wed, 2007-10-17 at 17:30 +0200, Peter Zijlstra wrote: > > > > > > > The thing is, swapper_space just calls ->writepage() and expects the > > > > page to be written out. So either the a_ops usage of swapper_space is > > > > deviant or NFS' is. > > > > > > Could somebody please document WTF writepage() is supposed to do, and > > > WTF page_mkwrite() is for? > > > > > > I thought that page_mkwrite() was supposed to finally allow us to deal > > > with dirty pages in a clean manner: the caller gets to tell the > > > filesystem that it wants the entire page written out, and then dirties > > > the page. What is the point if the VM then expects to be able to > > > circumvent this? > > > > Put differently: > > * _who_ is dirtying the page when the swapper is trying to write > > the page out? > > * why are they not calling either page_mkwrite() or > > commit_write()? > > I'm writing anonymous pages (I'm the crazy person doing swap over NFS). > And anonymous is dirty by default.
I'd really prefer to _know_ that these writes are coming from the swapper. That makes it possible to give them a correct credential and open context. Could you perhaps funnel them through a new a_op->swap_out() and default back to ->writepage() for those filesystems that don't define it? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
