Re: [PATCH v2 7/7] mm/page_owner: correct owner information for early allocated pages

From: Joonsoo Kim
Date: Sun Nov 23 2014 - 22:07:31 EST

On Fri, Nov 21, 2014 at 03:38:41PM -0800, Andrew Morton wrote:
> On Fri, 21 Nov 2014 17:14:06 +0900 Joonsoo Kim <> wrote:
> > Extended memory to store page owner information is initialized some time
> > later than that page allocator starts. Until initialization, many pages
> > can be allocated and they have no owner information. This make debugging
> > using page owner harder, so some fixup will be helpful.
> >
> > This patch fix up this situation by setting fake owner information
> > immediately after page extension is initialized. Information doesn't
> > tell the right owner, but, at least, it can tell whether page is
> > allocated or not, more correctly.
> >
> > On my testing, this patch catches 13343 early allocated pages, although
> > they are mostly allocated from page extension feature. Anyway, after then,
> > there is no page left that it is allocated and has no page owner flag.
> We really should have a Documentation/vm/page_owner.txt which explains
> all this stuff, provides examples, etc.

Okay. Will do in next spin.

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