lkml.org 
[lkml]   [2020]   [Jul]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: Re: Re: Re: [PATCH v18 01/14] mm/page_ext: Export lookup_page_ext() to GPL modules
Date
On Mon, 13 Jul 2020 19:38:05 +0200 SeongJae Park <sjpark@amazon.com> wrote:

> On Mon, 13 Jul 2020 20:19:09 +0300 Mike Rapoport <rppt@kernel.org> wrote:
>
> > On Mon, Jul 13, 2020 at 02:21:43PM +0200, SeongJae Park wrote:
> > > On Mon, 13 Jul 2020 15:08:42 +0300 Mike Rapoport <rppt@kernel.org> wrote:
> > >
> > > > Hi,
> > > >
> > > > On Mon, Jul 13, 2020 at 10:41:31AM +0200, SeongJae Park wrote:
> > > > > From: SeongJae Park <sjpark@amazon.de>
> > > > >
> > > > > This commit exports 'lookup_page_ext()' to GPL modules. It will be used
> > > > > by DAMON in following commit for the implementation of the region based
> > > > > sampling.
> > > >
> > > > Maybe I'm missing something, but why is DAMON a module?
> > >
> > > I made it loadable just for easier adoption from downstream kernels. I could
> > > drop the module build support if asked.
> >
> > Well, exporting core mm symbols to modules should be considred very
> > carefully.
>
> Agreed. I will drop the module support from the next spin.
>
> >
> > Why lookup_page_ext() is required for DAMON? It is not used anywhere in
> > this patchset.
>
> It's indirectly used. In the 6th patch, DAMON uses 'set_page_young()' to not
> interfere with other PTE Accessed bit users. And, 'set_page_young()' uses
> 'lookup_page_ext()' if !CONFIG_64BIT. That's why I exported it.

This also means that it would make no sense if !64BIT && !PAGE_EXTENSION. In
the next spin, I will update the DAMON Kconfig to select PAGE_EXTENSION if
!64BIT, as same to that of IDLE_PAGE_TRACKING.


Thanks,
SeongJae Park

\
 
 \ /
  Last update: 2020-07-17 12:00    [W:0.226 / U:0.408 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site