Re: [PATCH] mm: cma: fix accounting of CMA pages placed in high memory

Minchan Kim
2013-02-05T07:34:31Z

Hi Marek,

On Tue, Feb 05, 2013 at 08:10:19AM +0100, Marek Szyprowski wrote:
> Hello,
>
> On 2/5/2013 12:34 AM, Minchan Kim wrote:
> >On Mon, Feb 04, 2013 at 11:27:05AM +0100, Marek Szyprowski wrote:
> >> The total number of low memory pages is determined as
> >> totalram_pages - totalhigh_pages, so without this patch all CMA
> >> pageblocks placed in highmem were accounted to low memory.
> >
> >So what's the end user effect? With the effect, we have to decide
> >routing it on stable.
> >
> >>
> >> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> >> ---
> >> mm/page_alloc.c | 4 ++++
> >> 1 file changed, 4 insertions(+)
> >>
> >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> >> index f5bab0a..6415d93 100644
> >> --- a/mm/page_alloc.c
> >> +++ b/mm/page_alloc.c
> >> @@ -773,6 +773,10 @@ void __init init_cma_reserved_pageblock(struct page *page)
> >> set_pageblock_migratetype(page, MIGRATE_CMA);
> >> __free_pages(page, pageblock_order);
> >> totalram_pages += pageblock_nr_pages;
> >> +#ifdef CONFIG_HIGHMEM
> >
> >We don't need #ifdef/#endif.
>
> #ifdef is required to let this code compile when highmem is not enabled,
> becuase totalhigh_pages is defined as 0, see include/linux/highmem.h

Argh, Sorry for the noise.
I think it would be better to use accessor but it's a just nitpick. :)
Thanks!

>
> >> + if (PageHighMem(page))
> >> + totalhigh_pages += pageblock_nr_pages;
> >> +#endif
> >> }
> >> #endif
> >>
>
> Best regards
> --
> Marek Szyprowski
> Samsung Poland R&D Center
>
>
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--
Kind regards,
Minchan Kim