* Rik van Riel <riel@xxxxxxxxxx> [2010-02-04 10:41:14]: > Balbir Singh wrote: > >* Rik van Riel <riel@xxxxxxxxxx> [2010-02-04 08:40:43]: > > > >>On 02/03/2010 11:12 PM, Balbir Singh wrote: > >>>* Rik van Riel<riel@xxxxxxxxxx> [2010-02-03 16:11:03]: > >>> > >>>>Currently KVM pretends that pages with EPT mappings never got > >>>>accessed. This has some side effects in the VM, like swapping > >>>>out actively used guest pages and needlessly breaking up actively > >>>>used hugepages. > >>>> > >>>>We can avoid those very costly side effects by emulating the > >>>>accessed bit for EPT PTEs, which should only be slightly costly > >>>>because pages pass through page_referenced infrequently. > >>>Quite a clever implementation, one side effect is that one would see a > >>>larger number of minor faults with EPT enabled and an increase in > >>>allocation/frees of rmap entries, but that can be easily explained. > >>I suspect it won't be very many. I have been monitoring > >>/proc/meminfo on my system while testing this patch, and > >>it is quite typical that the size of the inactive anon > >>list does not change for minutes at a time. > >> > >>In other words, no pages are moved onto or off of the > >>inactive anon list for several minutes. That corresponds > >>to a very small number of minor faults introduced by my > >>patch. > >> > >>Of course, when the system is swapping, we will have more > >>minor faults. However, minor faults should be less of a > >>performance issue than major faults :) > >> > > > >I do agree with you. > > After 20 hours of uptime, it appears that this patch has > resolved the "KVM guests get swapped while buffer and page > cache stay in memory" problem my home system was experiencing. Is this with cgroups enabled as defined by the setup Jeff had? -- Balbir -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
