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


2014-10-24 오전 8:16, Gioh Kim 쓴 글:
>
>
> 2014-10-24 오전 5:36, Devendra Naga 쓴 글:
>> Hello,
>>
>> On Thu, Oct 23, 2014 at 6:22 PM, Gioh Kim <gioh.kim@lge.com> wrote:
>>> This patch shrink page-pool by page unit.
>>>
>>> Signed-off-by: Gioh Kim <gioh.kim@lge.com>
>>> ---
>>> 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.

Following is the correct code:
nr_freed = ion_page_pool_shrink(pool, gfp_mask, nr_to_scan);

>
>>
>>> + 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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>>
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