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SubjectRe: [PATCH] Swapping over network (and crypted loop and ...) made possible
Hi!

> > are always true. From now on, even if kswapd blocks on memory when
> > swapping, kreclaimd will notice extremely-low-on-memory situation and
> > will recover by freeing pages.
>
> That shouldn't be possible anyway: kswapd has the PF_MEMALLOC flag on
> the process set, so it should never, ever block on memory itself.

In case of swapping over network [I'm talking about nbd, not about
nfs!], it will be interrupt handler of network card which will try to
kmalloc(..., GFP_ATOMIC) and fail. Therefore, kswapd will be blocked
because it is waiting for ACK, because ACK was dropped because
kmalloc(..., GFP_ATOMIC) failed. I really don't think PF_MEMALLOC flag
will help deliver memory to network card's interrupt handler.

Pavel
--
I'm really pavel@ucw.cz. Look at http://195.113.31.123/~pavel. Pavel
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