Messages in this thread | | | Date | Mon, 06 Oct 2014 19:27:59 +0900 | From | Heesub Shin <> | Subject | Re: [PATCH 1/1] [ion]: system-heap use PAGE_ALLOC_COSTLY_ORDER for high order |
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Hello Kumar,
On 10/06/2014 05:31 PM, Pintu Kumar wrote: > The Android ion_system_heap uses allocation fallback mechanism > based on 8,4,0 order pages available in the system. > It changes gfp flags based on higher order allocation request. > This higher order value is hard-coded as 4, instead of using > the system defined higher order value. > Thus replacing this hard-coded value with PAGE_ALLOC_COSTLY_ORDER > which is defined as 3. > This will help mapping the higher order request in system heap with > the actual allocation request.
Quite reasonable.
Reviewed-by: Heesub Shin <heesub.shin@samsung.com>
BTW, Anyone knows how the allocation order (8,4 and 0) was decided? I think only Google guys might know the answer.
regards, heesub
> > Signed-off-by: Pintu Kumar <pintu.k@samsung.com> > --- > drivers/staging/android/ion/ion_system_heap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c > index da2a63c..e6c393f 100644 > --- a/drivers/staging/android/ion/ion_system_heap.c > +++ b/drivers/staging/android/ion/ion_system_heap.c > @@ -65,7 +65,7 @@ static struct page *alloc_buffer_page(struct ion_system_heap *heap, > } else { > gfp_t gfp_flags = low_order_gfp_flags; > > - if (order > 4) > + if (order > PAGE_ALLOC_COSTLY_ORDER) > gfp_flags = high_order_gfp_flags; > page = alloc_pages(gfp_flags | __GFP_COMP, order); > if (!page) > @@ -276,7 +276,7 @@ struct ion_heap *ion_system_heap_create(struct ion_platform_heap *unused) > struct ion_page_pool *pool; > gfp_t gfp_flags = low_order_gfp_flags; > > - if (orders[i] > 4) > + if (orders[i] > PAGE_ALLOC_COSTLY_ORDER) > gfp_flags = high_order_gfp_flags; > pool = ion_page_pool_create(gfp_flags, orders[i]); > if (!pool) >
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