On Fri, 4 Dec 2009 20:17:42 -0500 "J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote: > > > > How about this as an alternate. I have only compile tested it, nothing more. > > But if it looks good to you I'll make sure it really works. > > Well, without having really thinking about it: > > - If this were two separate patches, I'd have an easier time > sorting out the interesting stuff from the trivial (though > nevertheless good) hash-function reshuffling. I'll see what I can come up with... > - Adding code to the common lookup_and_check() instead of to > every caller certainly seems better, but too bad about the > special cases that remain. yeah.... I could possibly add a pass-by-reference to lookup_and_check which points to a possible cached value, but that would have only one user, so the special case would be moved elsewhere... ?? > - Something still seems odd here: we shouldn't ever have > duplicate cache entries with the same key, because during > their lifetimes cache entries are always kept in the hash. So > why do we need extra code to check for that case? I may just > be forgetting what we're doing here. Should I go reread the > rest of the series? When sunrpc_update_cache is called to update and item that is already valid, it unhashes that item and creates a new one. (The unhashed item disappears once all the refcounts go). So if we wait for user-space to update an entry for us, we might find out that it has been unhashed, so we need to find the new one. NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
