On Fri, Nov 18, 2011 at 8:43 AM, Marek Szyprowski m.szyprowski@samsung.com wrote:
Welcome everyone once again,
Please notice that this patch series is aimed to start further discussion. There are still few issues that need to be resolved before CMA will be really ready. The most hot problem is the issue with movable pages that causes migration to fail from time to time. Our investigation leads us to the point that these rare pages cannot be migrated because there are some pending io operations on them.
I am running a simple test to allocate contiguous regions and write a log on in a file on sdcard simultaneously. I can reproduce this migration failure 100% times with it. when I tracked the pages that failed to migrate, I found them on the buffer head lru list with a reference held on the buffer_head in the page, which causes drop_buffers() to fail.
So, i guess my question is, until all the migration failures are tracked down and fixed, is there a plan to retry the contiguous allocation from a new range in the CMA region?
~ sandeep