On Mon, Oct 21, 2013 at 11:26:43AM +0200, Vlastimil Babka wrote: > On 10/10/2013 11:46 PM, Johannes Weiner wrote: > > Hi everyone, > > > > here is an update to the cache sizing patches for 3.13. > > > > Changes in this revision > > > > o Drop frequency synchronization between refaulted and demoted pages > > and just straight up activate refaulting pages whose access > > frequency indicates they could stay in memory. This was suggested > > by Rik van Riel a looong time ago but misinterpretation of test > > results during early stages of development took me a while to > > overcome. It's still the same overall concept, but a little simpler > > and with even faster cache adaptation. Yay! > > Oh, I liked the previous approach with direct competition between the > refaulted and demoted page :) Doesn't the new approach favor the > refaulted page too much? No wonder it leads to faster cache adaptation, > but could it also cause degradations for workloads that don't benefit > from it? Were there any tests for performance regressions on workloads > that were not the target of the patchset?
If anything, it's unfair to refaulting pages because it requires 3 references before they are activated instead of the regular 2. We don't do the direct competition for regular in-core activation, either, which has the same theoretical problem but was never an issue in the real world. Not that I know of anyway. I ran a standard battery of mmtests (kernbench, dbench, postmark, micro, fsmark, what have you) and did not notice any regressions. -- 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/
