Re: [PATCH 1/3] mm: completely disable THP by transparent_hugepage=never

[Rik van Riel]

On 06/20/2011 01:07 PM, Cong Wang wrote:
> ä 2011å06æ21æ 00:58, Mel Gorman åé:
> > On Tue, Jun 21, 2011 at 12:34:28AM +0800, Amerigo Wang wrote:
> > > transparent_hugepage=never should mean to disable THP completely,
> > > otherwise we don't have a way to disable THP completely.
> > > The design is broken.
> >
> > I don't get why it's broken. Why would the user be prevented from
> > enabling it at runtime?
>
> We need to a way to totally disable it, right? Otherwise, when I configure
> THP in .config, I always have THP initialized even when I pass "=never".
>
> For me, if you don't provide such way to disable it, it is not flexible.
>
> I meet this problem when I try to disable THP in kdump kernel, there is
> no user of THP in kdump kernel, THP is a waste for kdump kernel. This is
> why I need to find a way to totally disable it.

What you have not explained yet is why having THP
halfway initialized (but not used, and without a
khugepaged thread) is a problem at all.

Why is it a problem for you?
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