Re: [RFC][PATCH] proc: export more page flags in /proc/kpageflags

From: KOSAKI Motohiro
Date: Tue Apr 14 2009 - 03:42:30 EST



> > > > > - PG_unevictable
> > > > > - PG_mlocked
>
> How about including PG_unevictable/PG_mlocked?
> They shall be meaningful to administrators.

I explained another mail. please see it.


> > this 9 flags shouldn't exported.
> > I can't imazine administrator use what purpose those flags.
>
> > > > > - PG_swapcache
> > > > > - PG_swapbacked
> > > > > - PG_poison
> > > > > - PG_compound
> >
> > I can agree this 4 flags.
> > However pagemap lack's hugepage considering.
> > if PG_compound exporting, we need more work.
>
> You mean to fold PG_head/PG_tail into PG_COMPOUND?
> Yes, that's a good simplification for end users.

Yes, I agree.


> > > > > - PG_NOPAGE: whether the page is present
> >
> > PM_NOT_PRESENT isn't enough?
>
> That would not be usable if you are going to do a system wide scan.
> PG_NOPAGE could help differentiate the 'no page' case from 'no flags'
> case.
>
> However PG_NOPAGE is more about the last resort. The system wide scan
> can be made much more efficient if we know the exact memory layouts.

Yup :)


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