From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Graf Subject: Re: [PATCH 7/9] rhashtable: Per bucket locks & deferred expansion/shrinking Date: Fri, 16 Jan 2015 21:36:05 +0000 Message-ID: <20150116213605.GE20315@casper.infradead.org> References: <20150116153415.GF30132@acer.localdomain> <20150116155835.GA15052@casper.infradead.org> <20150116160354.GI30132@acer.localdomain> <20150116161530.GC15052@casper.infradead.org> <20150116163202.GJ30132@acer.localdomain> <063D6719AE5E284EB5DD2968C1650D6D1CACADAF@AcuExch.aculab.com> <20150116165302.GE15052@casper.infradead.org> <20150116183626.GS30132@acer.localdomain> <20150116191831.GA26730@casper.infradead.org> <20150116193557.GU30132@acer.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Laight , "davem@davemloft.net" , "netdev@vger.kernel.org" , "herbert@gondor.apana.org.au" , "paulmck@linux.vnet.ibm.com" , "edumazet@google.com" , "john.r.fastabend@intel.com" , "josh@joshtriplett.org" , "netfilter-devel@vger.kernel.org" To: Patrick McHardy Return-path: Content-Disposition: inline In-Reply-To: <20150116193557.GU30132@acer.localdomain> Sender: netdev-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org On 01/16/15 at 07:35pm, Patrick McHardy wrote: > On 16.01, Thomas Graf wrote: > > Right,but that's a Netlink dump issue and not specific to rhashtable. > > Well, rhashtable (or generally resizing) will make it a lot worse. > Usually we at worst miss entries which were added during the dump, > which is made up by the notifications. > > With resizing we might miss anything, its completely undeterministic. > > > Putting the sequence number check in place should be sufficient > > for sets, right? > > I don't see how. The problem is that the ordering of the hash changes > and it will skip different entries than those that have already been > dumped. Since an resize can only be triggered through insert/remove you simply bump a sequence number when you insert/remove and have userspace restart the dump when NLM_F_DUMP_INTR is set.