On Thu, Jul 29, 2010 at 10:53:12AM +0900, Iram Shahzad wrote: > Hi > > I have found that memory compaction (CONFIG_COMPACTION) > is mainlined while looking at 2.6.35-rc5 source code. > I have a question regarding its dependency on HUGETLB_PAGE. > > While trying to use CONFIG_COMPACTION on ARM architecture, > I found that I cannot enable CONFIG_COMPACTION because > it depends on CONFIG_HUGETLB_PAGE which is not available > on ARM. > > I disabled the dependency and was able to build it. > And it looks like working! > > My question is: why does it depend on CONFIG_HUGETLB_PAGE? Because as the Kconfig says "Allows the compaction of memory for the allocation of huge pages.". Depending on compaction to satisfy other high-order allocation types is not likely to be a winning strategy. > Is it wrong to use it on ARM by disabling CONFIG_HUGETLB_PAGE? > It depends on why you need compaction. If it's for some device that requires high-order allocations (particularly if they are atomic), then it's not likely to work very well in the long term. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>