On 24.02, David Laight wrote: > From: Patrick McHardy > > On 24.02, Thomas Graf wrote: > > > On 02/23/15 at 03:06pm, Paul E. McKenney wrote: > > > > On Mon, Feb 23, 2015 at 05:32:52PM -0500, David Miller wrote: > > > > > I just did a quick scan of all code paths that do inserts into an > > > > > rhashtable, and it seems like all of them can easily block. So why > > > > > don't we do that? Make inserts sleep on an rhashtable expansion > > > > > waitq. > > > > > > > > > > There could even be a counter of pending inserts, so the expander can > > > > > decide to expand further before waking the inserting threads up. > > > > > > > > Should be reasonably simple, and certainly seems worth a try! > > > > > > Agreed. Definitely desirable for nft_hash. I like the pending counter > > > idea. I'm experimenting with various ideas on blocking inserts for > > > Netlink. Blocking too long might open DoS vectors as one app could > > > easily delay the creation of sockets for other applications. > > > > Regarding nft_hash, blocking in the netlink path certainly seems fine, > > but we will soon also have inserts from the packet processing path, > > where we obviously can't block. > > Why not an option to do a synchronous 'expand on insert' for > codepaths that can block? Sounds perfectly fine to me, just wanted to point out that we also need to handle the non-synchronous case properly. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
