On Thu, 12 Jul 2012, Minchan Kim wrote: > There is QA team in embedded company and they have tested their product. > In test scenario, they can allocate 100 high order allocation. > (they don't matter how many high order allocations in kernel are needed > during test. their concern is just only working well or fail of their > middleware/application) High order allocation will be serviced well > by natural buddy allocation without lumpy's help. So they released > the product and sold out all over the world. > Unfortunately, in real practice, sometime, 105 high order allocation was > needed rarely and fortunately, lumpy reclaim could help it so the product > doesn't have a problem until now. > If the QA team is going to consider upgrading to a kernel since lumpy reclaim has been removed, before they qualify such a kernel they would (hopefully) do some due diligence in running this workload and noticing the page allocation failure that is emitted to the kernel log for the high order page allocations. > If they use latest kernel, they will see the new config CONFIG_COMPACTION > which is very poor documentation, and they can't know it's replacement of > lumpy reclaim(even, they don't know lumpy reclaim) so they simply disable > that option for size optimization. Improving the description for CONFIG_COMPACTION or adding additional documentation in Documentation/vm would be very appreciated by both me and this hypothetical engineer :) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>