[Lustre-discuss] Swap over lustre
dave at thedillows.org
Wed Aug 17 20:42:25 PDT 2011
On Wed, 2011-08-17 at 22:57 -0400, Joe Landman wrote:
> The lustre client (and most NFS or even network block devices) all do
> memory allocation of buffers ... which is anathema to migrating pages
> out to disk. You can easily wind up in a "death spiral" race condition
> (and it sounds like you are there). You might be able to do something
> with iSCSI or SRP (though these also do block allocations and could
> trigger death spirals).
Your post is generally correct, but minor nit here: there is no memory
allocation on the command path of the Linux SRP initiator, so the death
spiral is not possible there. I suspect the iSCSI initiator takes
similar precautions -- or uses mempools -- to avoid this fate, but I'm
not as familiar with that code.
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