2011/11/18 Michal Nazarewicz mina86@mina86.com:
On Fri, 18 Nov 2011 22:20:48 +0100, sandeep patil psandeep.s@gmail.com wrote:
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?
No. Current CMA implementation will stick to the same range of pages also on consequent allocations of the same size.
Doesn't that mean the drivers that fail to allocate from contiguous DMA region will fail, if the migration fails?
~ sandeep