RE: [Linaro-mm-sig] [PATCH 12/15] drivers: add Contiguous Memory Allocator

Marek Szyprowski
2012-01-27T10:53:37Z

Hi Ohad,

On Friday, January 27, 2012 10:44 AM Ohad Ben-Cohen wrote:

> With v19, I can't seem to allocate big regions anymore (e.g. 101MiB).
> In particular, this seems to fail:
>
> On Thu, Jan 26, 2012 at 11:00 AM, Marek Szyprowski
> <m.szyprowski@samsung.com> wrote:
> > +static int cma_activate_area(unsigned long base_pfn, unsigned long count)
> > +{
> > +       unsigned long pfn = base_pfn;
> > +       unsigned i = count >> pageblock_order;
> > +       struct zone *zone;
> > +
> > +       WARN_ON_ONCE(!pfn_valid(pfn));
> > +       zone = page_zone(pfn_to_page(pfn));
> > +
> > +       do {
> > +               unsigned j;
> > +               base_pfn = pfn;
> > +               for (j = pageblock_nr_pages; j; --j, pfn++) {
> > +                       WARN_ON_ONCE(!pfn_valid(pfn));
> > +                       if (page_zone(pfn_to_page(pfn)) != zone)
> > +                               return -EINVAL;
>
> The above WARN_ON_ONCE is triggered, and then the conditional is
> asserted (page_zone() retuns a "Movable" zone, whereas zone is
> "Normal") and the function fails.
>
> This happens to me on OMAP4 with your 3.3-rc1-cma-v19 branch (and a
> bunch of remoteproc/rpmsg patches).
>
> Do big allocations work for you ?

I've tested it with 256MiB on Exynos4 platform. Could you check if the
problem also appears on 3.2-cma-v19 branch (I've uploaded it a few hours
ago) and 3.2-cma-v18? Both are available on our public repo:
git://git.infradead.org/users/kmpark/linux-samsung/

The above code has not been changed since v16, so I'm really surprised
that it causes problems. Maybe the memory configuration or layout has
been changed in 3.3-rc1 for OMAP4?

Best regards
--
Marek Szyprowski
Samsung Poland R&D Center