On Thu, May 29, 2014 at 05:09:34PM +0900, Gioh Kim wrote: > > >>>+ > >>> /* > >>> * Do the hard work of removing an element from the buddy allocator. > >>> * Call me with the zone->lock already held. > >>>@@ -1143,10 +1223,15 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype) > >>> static struct page *__rmqueue(struct zone *zone, unsigned int order, > >>> int migratetype) > >>> { > >>>- struct page *page; > >>>+ struct page *page = NULL; > >>>+ > >>>+ if (IS_ENABLED(CONFIG_CMA) && > >> > >>You might know that CONFIG_CMA is enabled and there is no CMA memory, because CONFIG_CMA_SIZE_MBYTES can be zero. > >>Is IS_ENABLED(CONFIG_CMA) alright in that case? > > > >next line checks whether zone->managed_cma_pages is positive or not. > >If there is no CMA memory, zone->managed_cma_pages will be zero and > >we will skip to call __rmqueue_cma(). > > Is IS_ENABLED(CONFIG_CMA) necessary? > What about if (migratetype == MIGRATE_MOVABLE && zone->managed_cma_pages) ? Yes, field, managed_cma_pages exists only if CONFIG_CMA is enabled, so removing IS_ENABLE(CONFIG_CMA) would break the build. Thanks. -- 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>