Messages in this thread |  | | Date | Thu, 6 Sep 2001 07:47:50 -0700 | From | Jonathan Lundell <> | Subject | Re: page pre-swapping + moving it on cache-list |
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At 2:21 PM +0100 2001-09-06, Alex Bligh - linux-kernel wrote: >It's not keeping it two lists that prevents proper >defragmentation. It's having it allocated all around >memory, and never freeing the pages which prevent >coalescence of areas, and thus either >throwing away the data, or garbage collecting, that >prevents defragmentation. We never free these pages >either because they sit in an idle system (with >no memory pressure) in places like >inactive_dirty, or in caches, or, in an active >system, because they are direct_reclaim'd out >of inactive_clean etc., so never get freed [1]. > >As this kind of garbage collection requires memcpy() >etc., it might be harmless when the system is >idle, but isn't going to be an attractive option when >the system is busy thrashing away (though it might be >possible to hueristically evict awkward pages >preferentially, by aging them more harshly).
The problem with thrashing, is it not, is that we're not making forward progress because we're waiting for swap--that is to say, thrashing *is* an idle state of sorts, and so might be an ideal opportunity for gc methods that require heavy CPU involvement. It's not as if there's anything better to do.... -- /Jonathan Lundell. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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