On Tue, 2005-08-09 at 15:25 -0300, Marcelo Tosatti wrote: > Hi Rik, > > Two hopefully useful comments: > > i) ARC and its variants requires additional information about page > replacement (namely whether the page has been reclaimed from the L1 or > L2 lists). > > How costly would it be to add this information to the hash table? > I've been thinking on reserving another word in the cache-line and use that as a bit-array to keep that information; the only problems with that would be atomicy of the {bucket,bit} tuple and very large cachelines where NUM_NR > 32.
> ii) From my reading of the patch, the provided "distance" information is > relative to each hash bucket. I'm unable to understand the distance metric > being useful if measured per-hash-bucket instead of globally? The assumption is that IFF the hash function has good distribution properties the per bucket distance is a good approximation of (distance >> nonres_shift). > > PS: Since remember_page() is always called with the zone->lru_lock held, > the preempt_disable/enable pair is unecessary at the moment... still, > might be better to leave it there for safety reasons. > There being multiple zones; owning zone->lru_lock does not guarantee uniqueness on the remember_page() path as its a global structure. -- Peter Zijlstra <[EMAIL PROTECTED]> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/