On Tue, Jan 14, 2014 at 04:35:33PM -0800, Andrew Morton wrote: > > Would it be overkill to save the kernel default both with and without thp > > and then doing a WARN_ON_ONCE() if a user-written value is ever less? > > Well, min_free_kbytes is a userspace thing, not a kernel thing - maybe > THP shouldn't be dinking with it. What effect is THP trying to achieve > and can we achieve it by other/better means? It moved logic from hugeadm where few people knew about it to the kernel. The value is related to anti-fragmentation. With the recommended setting the probability of mixing pages of different mobility within a single pageblock is reduced. Very very superficially, it reduces the number of instances the mm_page_alloc_extfrag tracepoint is triggered with parameters that are considered to be severely fragmenting. -- Mel Gorman SUSE Labs -- 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>