Messages in this thread | | | Subject | Re: [RESEND PATCH 1/2 -mm] mm: account lazy free pages separately | From | Yang Shi <> | Date | Wed, 14 Aug 2019 21:53:30 -0700 |
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On 8/14/19 5:49 AM, Vlastimil Babka wrote: > On 8/9/19 8:26 PM, Yang Shi wrote: >> Here the new counter is introduced for patch 2/2 to account deferred >> split THPs into available memory since NR_ANON_THPS may contain >> non-deferred split THPs. >> >> I could use an internal counter for deferred split THPs, but if it is >> accounted by mod_node_page_state, why not just show it in /proc/meminfo? > The answer to "Why not" is that it becomes part of userspace API (btw this > patchset should have CC'd linux-api@ - please do for further iterations) and > even if the implementation detail of deferred splitting might change in the > future, we'll basically have to keep the counter (even with 0 value) in > /proc/meminfo forever. > > Also, quite recently we have added the following counter: > > KReclaimable: Kernel allocations that the kernel will attempt to reclaim > under memory pressure. Includes SReclaimable (below), and other > direct allocations with a shrinker. > > Although THP allocations are not exactly "kernel allocations", once they are > unmapped, they are in fact kernel-only, so IMHO it wouldn't be a big stretch to > add the lazy THP pages there?
Thanks a lot for the suggestion. I agree it may be a good fit. Hope "kernel allocations" not cause confusion. But, we can explain in the documentation.
> >> Or we fix NR_ANON_THPS and show deferred split THPs in /proc/meminfo? >>
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