Messages in this thread | | | Date | Wed, 15 Jan 2014 15:22:18 +0000 | From | Mel Gorman <> | Subject | Re: [RFC] mm: show message when updating min_free_kbytes in thp |
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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
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