On 02/05/2013 03:10 PM, 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@xxxxxxxxxxx>
> ---
> 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
Hi Marek,
1) Why can support CMA regions placed in highmem? CMA is for dma buffer,
correct? Then how can old dma device access highmem?
2) Why there is no totalhigh_pages variable define in the case of config
highmem?
> + if (PageHighMem(page))
> + totalhigh_pages += pageblock_nr_pages;
> +#endif
> }
> #endif
>
Best regards
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