On Thu, 2005-12-15 at 00:21 -0800, David S. Miller wrote: > From: Sridhar Samudrala <[EMAIL PROTECTED]> > Date: Wed, 14 Dec 2005 23:37:37 -0800 (PST) > > > Instead, you seem to be suggesting in_emergency to be set dynamically > > when we are about to run out of ATOMIC memory. Is this right? > > Not when we run out, but rather when we reach some low water mark, the > "critical sockets" would still use GFP_ATOMIC memory but only > "critical sockets" would be allowed to do so. > > But even this has faults, consider the IPSEC scenerio I mentioned, and > this applies to any kind of encapsulation actually, even simple > tunneling examples can be concocted which make the "critical socket" > idea fail. > > The knee jerk reaction is "mark IPSEC's sockets critical, and mark the > tunneling allocations critical, and... and..." well you have > GFP_ATOMIC then my friend. > > In short, these "seperate page pool" and "critical socket" ideas do > not work and we need a different solution, I'm sorry folks spent so > much time on them, but they are heavily flawed.
maybe it should be approached from the other side; having a way to mark connections as low priority (say incoming http connections to your webserver) or as non-critical/expendable would give the "normal" GFP_ATOMIC ones a better chance in case of overload/DDOS etc. It's not going to solve the VM deadlock issue wrt iscsi/nfs; however it might be useful in the "survive slashdot" sense... - 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
