Hi Nai, On Wed, May 16, 2012 at 01:25:34PM +0800, nai.xia wrote: > Hi Johannes, > > Just out of curiosity(since I didn't study deep into the > reclaiming algorithms), I can recall from here that around 2005, > there was an(or some?) implementation of the "Clock-pro" algorithm > which also have the idea of "reuse distance", but it seems that algo > did not work well enough to get merged? Does this patch series finally > solve the problem(s) with "Clock-pro" or totally doesn't have to worry > about the similar problems? As far as I understood, clock-pro set out to solve more problems than my patch set and it failed to satisfy everybody. The main error case was that it could not partially cache data of a set that was bigger than memory. Instead, looping over the file repeatedly always has to read every single page because the most recent page allocations would push out the pages needed in the nearest future. I never promised to solve this problem in the first place. But giving more memory to the big looping load is not useful in our current situation, and at least my code protects smaller sets of active cache from these loops. So it's not optimal, but it sucks only half as much :) There may have been improvements from clock-pro, but it's hard to get code merged that does not behave as expected in theory with nobody understanding what's going on. My code is fairly simple, works for the tests I've done and the behaviour observed so far is understood (at least by me). -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
