On Wed, Jul 29, 2015 at 12:55:54PM +0200, Daniel Vetter wrote:
On Wed, Jul 29, 2015 at 11:49:45AM +0100, Mel Gorman wrote:
On Mon, Jul 13, 2015 at 05:35:15PM +0900, Gioh Kim wrote:
My ARM-based platform occured severe fragmentation problem after long-term (several days) test. Sometimes even order-3 page allocation failed. It has memory size 512MB ~ 1024MB. 30% ~ 40% memory is consumed for graphic processing and 20~30 memory is reserved for zram.
The primary motivation of this series is to reduce fragmentation by allowing more kernel pages to be moved. Conceptually that is a worthwhile goal but there should be at least one major in-kernel user and while balloon pages were a good starting point, I think we really need to see what the zram changes look like at the same time.
I think gpu drivers really would be the perfect candidate for compacting kernel page allocations. And this also seems the primary motivation for this patch series, so I think that's really what we should use to judge these patches.
Of course then there's the seemingly eternal chicken/egg problem of upstream gpu drivers for SoCs :(
I recognised that the driver he had modified was not an in-tree user so it did not really help the review or the design. I did not think it was very fair to ask that an in-tree GPU driver be converted when it would not help the embedded platform of interest. Converting zram is both a useful illustration of the aops requirements and is expected to be beneficial on the embedded platform. Now, if a GPU driver author was willing to convert theirs as an example then that would be useful!