Messages in this thread Patch in this message | | | Subject | Re: [PATCH 05/19] NFS: Use local caching | From | Trond Myklebust <> | Date | Wed, 15 Nov 2006 11:52:45 -0500 |
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On Wed, 2006-11-15 at 16:00 +0000, David Howells wrote: > Trond Myklebust <trond.myklebust@fys.uio.no> wrote: > > > Why is fscache being given a vote on whether or not the NFS page can be > > removed from the mapping? If the file has changed on the server, so that > > we have to invalidate the mapping, then I don't care about the fact that > > fscache is busy: the page has to go. > > This is releasepage() not invalidatepage(). It is conditional.
...and invalidate_complete_page2() calls try_to_release_page() which again calls releasepage(). Success or failure of the latter should therefore not depend on the internal fscache state.
> > > @@ -942,11 +954,13 @@ static int nfs_update_inode(struct inode > > > ... > > > + nfs_fscache_set_size(inode); > > > > Doesn't nfs_fscache_set_size try to grab rw_semaphores? This function is > > _always_ called with the inode->i_lock spinlock held. > > Hmmm... I wonder if I need to do this in nfs_update_inode() at all. Won't the > pages and the cache object attached to an inode be discarded anyway if the file > attributes returned by the server change?
In the case of a read-only file, yes. That is not true of a read/write file.
> > > static void nfs_readpage_release(struct nfs_page *req) > > > { > > > + struct inode *d_inode = req->wb_context->dentry->d_inode; > > > + > > > + if (PageUptodate(req->wb_page)) > > > + nfs_readpage_to_fscache(d_inode, req->wb_page, 0); > > > + > > > > Will usually be called from an rpciod context. Should therefore not be > > grabbing semaphores, doing memory allocation etc. > > Is it possible to make an NFS kernel thread that can have completed nfs_page > structs queued for writing to the cache?
Why should we add extra context switches for the non-fscache case? Just move the call to nfs_readpage_to_fscache into its own kernel thread.
Trond
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