Messages in this thread |  | | | Date | Wed, 19 Aug 2009 21:25:56 +0900 | | Subject | Re: [RFC] respect the referenced bit of KVM guest pages? | | From | Minchan Kim <> |
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On Wed, Aug 19, 2009 at 9:10 PM, Wu Fengguang<fengguang.wu@intel.com> wrote: > On Wed, Aug 19, 2009 at 08:05:19PM +0800, KOSAKI Motohiro wrote: >> >> page_referenced_file? >> >> I think we should change page_referenced(). >> > >> > Yeah, good catch. >> > >> >> >> >> Instead, How about this? >> >> ============================================== >> >> >> >> Subject: [PATCH] mm: stop circulating of referenced mlocked pages >> >> >> >> Currently, mlock() systemcall doesn't gurantee to mark the page PG_Mlocked >> > >> > mark PG_mlocked >> > >> >> because some race prevent page grabbing. >> >> In that case, instead vmscan move the page to unevictable lru. >> >> >> >> However, Recently Wu Fengguang pointed out current vmscan logic isn't so >> >> efficient. >> >> mlocked page can move circulatly active and inactive list because >> >> vmscan check the page is referenced _before_ cull mlocked page. >> >> >> >> Plus, vmscan should mark PG_Mlocked when cull mlocked page. >> > >> > PG_mlocked >> > >> >> Otherwise vm stastics show strange number. >> >> >> >> This patch does that. >> > >> > Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> >> >> Thanks. >> >> >> >> >> Index: b/mm/rmap.c >> >> =================================================================== >> >> --- a/mm/rmap.c 2009-08-18 19:48:14.000000000 +0900 >> >> +++ b/mm/rmap.c 2009-08-18 23:47:34.000000000 +0900 >> >> @@ -362,7 +362,9 @@ static int page_referenced_one(struct pa >> >> * unevictable list. >> >> */ >> >> if (vma->vm_flags & VM_LOCKED) { >> >> - *mapcount = 1; /* break early from loop */ >> >> + *mapcount = 1; /* break early from loop */ >> >> + *vm_flags |= VM_LOCKED; /* for prevent to move active list */ >> > >> >> + try_set_page_mlocked(vma, page); >> > >> > That call is not absolutely necessary? >> >> Why? I haven't catch your point. > > Because we'll eventually hit another try_set_page_mlocked() when > trying to unmap the page. Ie. duplicated with another call you added > in this patch.
Yes. we don't have to call it and we can make patch simple. I already sent patch on yesterday.
http://marc.info/?l=linux-mm&m=125059325722370&w=2
I think It's more simple than KOSAKI's idea. Is any problem in my patch ?
> > Thanks, > Fengguang > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> >
-- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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