Messages in this thread | | | Date | Fri, 4 Dec 2009 14:16:17 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH 2/9] ksm: let shared pages be swappable |
| |
On Fri, 4 Dec 2009 14:06:07 +0900 (JST) KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
> > Umm?? Personally I don't like knob. If you have problematic workload, > > please tell it us. I will try to make reproduce environment on my box. > > If current code doesn't works on KVM or something-else, I really want > > to fix it. > > > > I think Larry's trylock idea and your 64 young bit idea can be combinate. > > I only oppose the page move to inactive list without clear young bit. IOW, > > if VM pressure is very low and the page have lots young bit, the page should > > go back active list although trylock(ptelock) isn't contended. > > > > But unfortunatelly I don't have problem workload as you mentioned. Anyway > > we need evaluate way to your idea. We obviouslly more info. > > [Off topic start] > > Windows kernel have zero page thread and it clear the pages in free list > periodically. because many windows subsystem prerefer zero filled page. > hen, if we use windows guest, zero filled page have plenty mapcount rather > than other typical sharing pages, I guess. > > So, can we mark as unevictable to zero filled ksm page? >
Hmm, can't we use ZERO_PAGE we have now ? If do so, - no mapcount check - never on LRU - don't have to maintain shared information because ZERO_PAGE itself has copy-on-write nature.
Thanks, -Kame
| |