Re: [RFC 1/2] staging: ion: shrink page-pool by page unit

[Gioh Kim]

2014-10-24 ìì 5:36, Devendra Naga ì ê:
> Hello,
>
> On Thu, Oct 23, 2014 at 6:22 PM, Gioh Kim <gioh.kim@xxxxxxx> wrote:
> > This patch shrink page-pool by page unit.
> >
> > Signed-off-by: Gioh Kim <gioh.kim@xxxxxxx>
> > ---
> >   drivers/staging/android/ion/ion_page_pool.c   |    5 +++--
> >   drivers/staging/android/ion/ion_system_heap.c |    7 +++++--
> >   2 files changed, 8 insertions(+), 4 deletions(-)
>
> >
>
> --- cut --
>
> > diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c
> > index da2a63c..36e73c3 100644
> > --- a/drivers/staging/android/ion/ion_system_heap.c
> > +++ b/drivers/staging/android/ion/ion_system_heap.c
> > @@ -211,7 +211,7 @@ static int ion_system_heap_shrink(struct ion_heap *heap, gfp_t gfp_mask,
> >                                          int nr_to_scan)
> >   {
> >          struct ion_system_heap *sys_heap;
> > -       int nr_total = 0;
> > +       int nr_total = 0, nr_freed;
> >          int i;
> >
> >          sys_heap = container_of(heap, struct ion_system_heap, heap);
> > @@ -219,7 +219,10 @@ static int ion_system_heap_shrink(struct ion_heap *heap, gfp_t gfp_mask,
> >          for (i = 0; i < num_orders; i++) {
> >                  struct ion_page_pool *pool = sys_heap->pools[i];
> >
> > -               nr_total += ion_page_pool_shrink(pool, gfp_mask, nr_to_scan);
> > +               nr_freed += ion_page_pool_shrink(pool, gfp_mask, nr_to_scan);
>
> nr_freed is not initialised to zero. This might result in updating of
> a garbage value stored initially after nr_freed is created.

Yes, your're right. It's my mistake.
I testes this on my platform with custom kernel and copied codes.
I missed a line for it.
I'm sorry.

> > +               nr_total += nr_freed;
> > +               /* nr_to_scan can be negative */
> > +               nr_to_scan -= nr_freed;
> >          }
> >
> >          return nr_total;
> > --
> > 1.7.9.5
> >
> > --
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