Messages in this thread | | | Date | Tue, 29 Jan 2002 09:28:58 -0800 | From | Josh MacDonald <> | Subject | Re: [reiserfs-dev] Re: Note describing poor dcache utilization under high memory pressure |
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Quoting Alexander Viro (viro@math.psu.edu): > > > On Tue, 29 Jan 2002, Hans Reiser wrote: > > > This fails to recover an object (e.g. dcache entry) which is used once, > > and then spends a year in cache on the same page as an object which is > > hot all the time. This means that the hot set of objects becomes > > diffused over an order of magnitude more pages than if garbage > > collection squeezes them all together. That makes for very poor caching. > > Any GC that is going to move active dentries around is out of question. > It would need a locking of such strength that you would be the first > to cry bloody murder - about 5 seconds after you look at the scalability > benchmarks.
We're not talking about actively referenced entries, we're talking about entries on the d_lru list with zero references. Relocating those objects should not require any more locking than currently required to remove and re-insert the dcache entry. Right?
-josh
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