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    SubjectRe: [RFC][PATCH 0/3] TCP/IP Critical socket communication mechanism
    On Thu, 2005-12-15 at 00:21 -0800, David S. Miller wrote:
    > From: Sridhar Samudrala <>
    > 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...

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      Last update: 2005-12-15 09:38    [W:0.027 / U:10.184 seconds]
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