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.s...@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 <pint...@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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