From: BlaisorBlade <bla...@ya...> - 2004-04-12 14:53:28
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Alle 19:07, sabato 10 aprile 2004, Jeff Dike ha scritto: > On Sat, Apr 10, 2004 at 04:00:25PM +0200, Sven K=F6hler wrote: > > what's so bad about it? > > It can put the host at risk. There's a VM system for a reason, and it > needs swap in order to be able to back out of memory shortages. mlocking > large amounts of memory subverts that and increases the possibility of > deadlocking. Well, it is true, but also reducing memory on the host increases the=20 possibility of OOM (not deadlock - only processes killed; you can deadlock= =20 only with the OOM killer, but with late 2.4 kernels you can disable it). What is true is that mlock()ing cache memory is meaningless; each file shou= ld=20 be cached either on the host or on the guest; it is better to reduce cache= =20 memory size, by subtracting memory to UML. If we use humfs and mmap(), then we get that cache exist only on the host (= and=20 is mmap'ed on the guest). So we could mlock the memory actually used by UML= =20 (for instance the UML kernel, which should never be swapped). =2D-=20 Paolo Giarrusso, aka Blaisorblade Linux registered user n. 292729 |