On Fri, Nov 30, 2012 at 03:02:54PM +0100, Florian Westphal wrote: > Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> wrote: > > Quick idea: I think we can also support atomic replacement at word > > size using xchg, so the replacement operation can still happen at word > > level. Setting many bits at once would be also faster with that. > > Unfortunately, no -- the interface is too rudimentary. > Example: You want to set bis 0, 2, 6; but leave all other > bit that are set intact. > > So you first need to make a dump to fetch the current labels set. > Then, you set bits 0, 2, 6 and send the new state to the kernel. > > But between the dump and the set operation, a new bit might > have been set. So even when using xchg it will be un-set again... what about cmpxchg inside a loop? I think we can assume that the probability of interference while updating a word is low. -- 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
