On Monday August 14, [EMAIL PROTECTED] wrote: > On Sun, 2006-08-13 at 22:22 -0700, Andrew Morton wrote: > > > > We could track dirty anonymous memory and throttle. > > > > Also, there must be some value of /proc/sys/vm/min_free_kbytes at which a > > machine is no longer deadlockable with any of these tricks. Do we know > > what level that is? > > Not sure, the theoretical max amount of memory one can 'lose' in socket > wait queues is well over the amount of physical memory we have in > machines today (even for SGI); this combined with the fact that we limit > the memory in some way to avoid DoS attacks, could make for all memory > to be stuck in wait queues. Of course this becomes rather more unlikely > for ever larger amounts of memory. But unlikely is never a guarantee.
What is the minimum amount of memory we need to reserve for each socket? 1K? 1 page? Call it X Suppose that whenever a socket is created (or bound or connected or whatever is right) we first allocate that much to a recv pool. If any socket has less than X queued, then it is allowed to allocate up to a total of X from the reserve pool. After that it can only receive when memory can be allocated from elsewhere. Then we will never block on recv. Note that X doesn't need to be the biggest possible incoming message. It only needs to be enough to get an 'ack' over any possible network storage protocol with any possible layering. I suspect that it well within one page. Would it be too much waste to reserve one page for every idle socket? Does this have some fatal flaw? NeilBrown - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
